Slow deformed growth, and brittle plants....

colonel

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Nov 25, 2005
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I was just wondering if anyone had any ideas as to why my plants would be so brittle and slow to grow.... I have been working on getting my tank in shape, and have gotten a lot of help over at the AGA forums and things have improved since I started. I havnt changed anything for about 2-3 weeks now and this is how things have been running...
75 g. 194 watts of lighting
50% weekly WC, 1 t. epsom salts added after.
GH is 5.5 (water company told me that it Ca is 26 ppm, and Mg at 6 ppm)
Ferts:
1/2 t. KNO3 3x/week
1/8 t. KH2PO4 3x/week
15 ml. flourish traces 3x/week
15 ml flourish Iron 3x/week
CO2 between 30-40 ppm... seems to raise all through the day peaking around 40 ppm or so....
I just stopped adding the extra iron because I dont really feel I need it, I originally started adding it because on some plants leaves are coming in pale, a cream color, to light yellowish. but after adding iron for a few weeks there was no change at all in that so i figured it wasnt iron related. and other than new leaves coming in like that on Anubias, Echinodorus, and Marsilea.
All of my stem plants are affected by pretty much the same syptoms which is mainly very slow growth (i know this tank isnt very high light, however I have seen much quicker growth out of it in the past) and extremely brittle stems and leaves, so brittle that if they are bent past 90 degrees or so they will simply break. Then on some of the stem plants but not all, they show deformed new growth... leaves coming in that dont even look like leaves on A. reineckii, and other plants that simply have cupped leaves, or folded leaf edges.
Any ideas of what could be causing this? possibly to much of a nutrient? or not enough of something else? At first I though it was Ca, but after reading Toms article... and with a GH of 5 that just doesnt seem possible, then I thought maybe Mg could be causing it for some reason.... but I have been adding a pretty large amound of epsom salts at WC... maybe to much Mg? or not enough traces? i have read boron is similar to Ca def.
I really dont have a clue.... but something seems off.... i dont remember my plants being so easily broken before.... and the growth just seems so slow..... its taken about 2 weeks for H. polysperma to reach the top of my tank..... and in about 3 or 4 weeks time R. rotundifolia has grown only about 4" if that after I pruned it about a month or more ago...... Maybe im expecting to see to much out of this tank..... i just remember it growing better when i read the PMDD paper and mixed everything into a solution and dosed a few ml of that each day..... i cant figure out what I did to make things slow down so much.
thanks for any help
Matt
 

defdac

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Re: Slow deformed growth, and brittle plants....

You describe my own tank pretty much and we have very similar water, but I have even lower GH (~3) but a Ca of 22 ppm and Mg of 2.3 ppm. KH at 3.1. This is how my A. reineckii looked like:
http://www.defblog.se/pictures/picture1542.jpg
Most stem plants were very brittle also.

I have hunted this "deficiency" a couple of years and it was not until I really wanted to grow R. wallichii and saw Edwards post about hinting that high Mg (>10) in low KH waters seems to have adverse effects:
http://www.aquaticplantcentral.com/forumapc/showthread.php?t=9519&page=3
Before I tried various levels of CaCl2, CaCO3 and Dolomite without luck. It would rather seem that fiddeling with the GH only had bad effects, stunted growth and so on.

I and a couple of fellow aquarists here in Sweden with soft water confirm their Calcium deficiencies went away after they stopped using MgSO4.

I've never been able to grow R. wallichii before, but now I can.

Using MgSO4 is like turning a Calcium-deficiency-switch on and off for me and a couple of others here in Sweden.

Yes I know this is totally against what Tom Barr usually says, but this is too obvious and to easy for us here in Sweden to test - so I would *love* an explanation why this happens.
 

Milan

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Sep 28, 2005
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Re: Slow deformed growth, and brittle plants....

Colonel, what you described looks like a mirror image to what I'm experiencing lately with my plants. Cupped leaves, stunned/deformed growth, very brittle stems, ....
Here is what happened to me. I mistakenly mixed up labels on containers with MgSO4 and KH2PO4 (these chemicals look exactly the same in dry form). Dosing MgSO4 instead of KH2PO4 obviously resulted in PO4 limitation, so I kept further increasing dosage of so called phosphates until I became very suspicious and discovered the mishap. I'm not sure exactly how long this lasted, but probably over a month :( . Instead of supplying PO4, I was boosting Mg, and I didn't bother testing the GH, since it's never been an issue with my tap water.

I'm very convinced the Mg is to blame.
 

colonel

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Nov 25, 2005
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Re: Slow deformed growth, and brittle plants....

wow, pretty intresting stuff, didnt think anyone was going to reply to this one Im really glad your guys did.
defdac, that picture of A. reineckii is EXACTLY how mine has been growing in.... well lack there of really, LoL my plants really havnt grown much in the past few months..... ever since I swiched up to EI doseing.... and I really dont think it has a THING at all to do with the EI method.... but rather could be somthing to do with Mg as you both have stated and found out to be true in your tanks. Because I can also point back to when I started EI i was concerned about there being a lack of Mg in my water.... so i have been dumping the stuff in at water changes thinking it was needed..... even though Tom recomended only adding 1/4 tsp. i figured it needed to be up around 10 ppm as sometimes recomended here and there on the net. So the whole time I have had this problem I have also had high Mg, I would say above 10 ppm.....
And I noticed before this much faster growth from my plants when i was doseing everything all mixed up in a liquid solution... only there was deficiences i believe in PO4 and NO3 then because i was doseing very little NO3 and no PO4.... even so growth was better than lately.... several inches a week from my stem plants..... and the tops always looked good.... it was just the bottomes dieing off.
when i was doseing this mixed up solution it did indeed have Mg in it..... but through the entire week the tank was only getting a total of .35 ppm added to it, along with about 25% weekly water changes.... only a mere PINCH at water changed compared to theTEASPOON that has been added...... sometimes even 2 t. thinking i needed more for some stupid reason.
Thank you VERY much for the input that is definantly something for me to look into..... actually really the only explaination I can come up as to why things would have slowed down since swiching ways I add ferts. Im going to do a nice big water change and leave my water alone as was recomended.... I will post in a week or two and let all know if there has been any positive change from this. thanks again happy holidays all!
Matt
 

Tom Barr

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Re: Slow deformed growth, and brittle plants....

This also seems like poor CO2, stem plants get brittle and stop growing when CO2 is low.

You can see this in a number of species.

That cupping is not Mg/Ca related.

You might think it is, but I have shown it was also done when you vary the CO2.

All plants would not become so brittle and stop growing unless something major occurred.

NPK, CO2............

So I'd suggest looking there.

Adding a little Mg is fine, but too much might cause issues in soft water(but not hard water).
I've never suggested that folks add a lot of Mg.
SeaChem eq and the GH builds etc do fine on their own.

I do not know the effective range of Mg, Ca is very high though.

Regards,
Tom Barr

Regards,
Tom Barr
 

Milan

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Re: Slow deformed growth, and brittle plants....

Tom Barr said:
This also seems like poor CO2, stem plants get brittle and stop growing when CO2 is low.

Tom, this could very well be the case. Until recently I was using a DIY CO2. However, the symptoms of Ca deficiency (cupped leaves, spaghetti stems ..) coincide with the mishap with MgSO4. Mind, you Mg was probably grossly overdosed ...
 

Tom Barr

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Re: Slow deformed growth, and brittle plants....

Then it's most certainly CO2.

Mg deficency does occur, but it much rarer than many think.
Many get on the Mg, K, N, etc bandwagon to blame all their problems.
Don't fret, many folks do it and this helps to better understand things, but too many just assume that is the case, without testing it.

CO2 is still 90% of this hobby.
Always look there and before make much judgements on mysteries elsewhere, try to be as confident as you can with that.

That one issue has caused more problems than any other, certainly far more than Mg.

Brittle stems always is a sign of low CO2, add some slow growth of fast growing weeds, then you really can see the differences.

Regards,
Tom Barr
 

colonel

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Nov 25, 2005
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Re: Slow deformed growth, and brittle plants....

In my tank for the past few weeks CO2 has been really consistant.... but that hasnt been the case in the past few months. I was first getting it up and it was changing day to day as I was raising it..... then my tank was empty and needed refilled, and up intil about 2 weeks ago I was still fiddling with levels to get them there. Now any higher and my fish are gasping at the top of the tank. An hour or so after CO2 comes on i hit ph of 6.5 and by the end of the day I am consistant in the 6.2-6.3 range with a KH of 3.... leads me to believe what the chart says and what the fish say are pretty close with where CO2 levels are....
as far as Mg my water is fairly soft out of the tap.... Kh 2.5 and GH of 5.5 seems like adding to much Mg could cause problems with my water and thats what I have been doing so im going to be cutting back on that to see if it helps. hope I see a difference. thought maybe it is something else all togeather..... maybe I dont have enough CO2 or NPK.... I dunno those seem covered though.
Matt
 

Tom Barr

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Re: Slow deformed growth, and brittle plants....

Well, adding a 1/4 teaspoon of MgSO4 once a week per 20 gal will rule out any Mg issue.
When you increase CO2, make sure to have a decent surface flow, not waves, but certainly some decent flow.

This will help the fish, as will adding CO2 during the light peroid only.
CO2 mist can also help add more CO2 to the plants with less harm to the fish.

From there adding more KNO3/KH2PO4/Traces/some MgSO4 to rule that out should take care of it. It might takea 1-3 weeks of good work to whip the tank back into good shape, but it does not take longer than that, you are not doing something right if it takes longer than about 3 weeks.

Regards,
Tom Barr
 

reiverix

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Re: Slow deformed growth, and brittle plants....

I've been experimenting with CO2 levels for a few weeks just to see what effects it would have. I've been suspicious about the pH/KH calculations especially since I have several pieces of driftwood that I reckon gives me false readings. So now I'm up to 45ppm CO2 with no adverse affect to my livestock. I have to say that my A. reineckii has put on a new lease of life. The increase in mass is astounding. My R. macaranda also sprouted like there's no tomorrow.

My tapwater is very low in KH. Mg and calcium are also low and I dose these quite liberally at 10ppm Mg and 40ppm Ca every week afer a 50% water change. Nearly forgot, I also ran out of CSM+B and have been using Flourish for a few weeks.

I may cut back on the Mg to see if there is any change. Not so sure about the Ca as my snails start dying off if I go lower.
 

colonel

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Re: Slow deformed growth, and brittle plants....

welp I could really use some help, I havnt changed anything in my tank for almost a month now so everything has been stable, but sadly there hasnt been much of any improvement at all. I would say about 3 and a half weeks ago I stopped adding things to adjust the GH all togeather, but for some reason over the week the GH in my tank is raising a few degrees? pretty much most of the deformed growth did stop, I still get some folded leaf edges on H. polysperma here and there but other than that everything looks pretty normal.
Though the plants still dont look very healthy, new leaves of Anubias, Echinodorus, and Marsilea still come in light, sort of pale yellowish tinge to them. I can say that they do look a bit better but not more... they are coming in a bit more yellow than the pale cream color they were coming in before. The entire leave of marsilea and Anubias come in like that, but on the one Echinodorus I have in there the leaves are the red color they should be with just the veins coming in pale like that.
Myriophyllum sp. and pretty much the rest of the stem plants, but it is best seen on myrio. have growth tips that do look slightly better than before nice and green, but then as the plant grows a bit more all the old growth fades out to a dull green, almost yellow at the bottom, and at times the lower old leaves fall off. I mean just over all health doesnt look to good at all, and as usual there is hardly any growth, everything is just sort of sitting....
does ANYONE have ANY ideas of what could be going on, or what needs to be done to get healthy plant growth? I have no clue what to do nor why things arnt flourishing.... and to tell you the truth i am getting really frustrated, to the point of about being ready to give up, I have been tinkering with this for almost a year... and havnt seen any major improvements.... to be honest I think the tank looked better when I first started with DIY CO2, and doseing via "PMDD"....
If anyone needs water param's or something let me know i would be happy to list whatever that isnt already listed from previous post.... right now im not even in the mood to really think about it
any help would be very very very much appriciated.... thanks everyone
Matt
 

colonel

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Nov 25, 2005
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Re: Slow deformed growth, and brittle plants....

Well I had taken a glass of water from the tap yesterday to rest 24 hours to test to see what im starting with. So i decided to go ahead and do that and test tank water also since I usually change my water tonight, or tomorrow depending on the week.....
Tap-
PH- 7.6
GH- 6.5 degrees
KH- 2.5 degrees
Ca- 35 ppm
Mg- 7 ppm
Ca:Mg ratio - about 5:1

Tank-
PH- 6.1
GH- 9.5 degrees
KH- 6 degrees
Ca- 45 ppm
Mg- 14 ppm
Ca:Mg ratio - about 3.2:1

Now for how I have been doseing the tank, which like I had said before nothing has changed in the past month or so, everything has been held consistant.
75 gallon tank... probably close to about 60 gallons actual water?
194 watts of lighting (just upgraded yesterday to 260 watts... though as it was just yesterday it would have no effect on the things happening over the past 4 weeks)

KNO3 - 3/4 tsp. 3x/week
KH2PO4 - 3/16 tsp. 3x...
K2SO4 - 1/4 tsp 3x...
Traces - 20 ml 3x...
Extra Iron (flourish iron) - 7.5 ml 3x...

At water change I have been adding 1 tsp. baking soda to raise KH because I was afraid PH was going to low.... I am now going to stop and leave things where they are as far as KH goes.... and like I said earlier i stopped adding things to change GH almost 4 weeks ago.

What I dont understand is why my GH is going up over the week? is it possible that from adding Seachem Eq, and things like epsom salts and CaSO4 to alter the GH.... that they have settled in the substrate and are slowly leaching into the water? I also had a small sea shell in the back of the tank making a cave for some of the fish to hide in, which I just removed today... is it possible that it was dissloving leaching Ca and Mg into the water? thought before I added things to change GH this shell was in the tank and it always held stable around 6 degrees... I dont really know what to make of this?

It seems to me that nutrients are more than covered and it would be safe to say that this problem isnt from lack of something.... I really think I have plenty of CO2 also, though the CO2 chart says that with a ph of 6.1 and KH of 6 that I would have a CO2 concentration of 143 ppm which could not possibly be right, else I would think my fish would be dead.
Im at a loss of what to do... seems like no matter what changes I make to the tank, plant health doesnt improve... any input would be appriciated.....
 

Aquaman

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Mar 20, 2005
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Re: Slow deformed growth, and brittle plants....

Your additions are probably outstripping your useage since your growth is
limited right now. The GH is rising because of these additions. If you were
using a TDS meter( approx. $70) you would be surprised at how direct the
relationship is even when plants are growing well. You did not mention what
substrate you are using and how old it is. Check and see if the crown plant
roots have precipitated iron oxide on them(reddish brown color). Try Flourish
tabs or a little peat fiber at the roots of the affected plants. Shove it into the substrate one inch or so offset from the crown(further for some crypts).
Run an airstone at night and raise the nighttime Redox. Also, I would do a
large water change (75%) and not dose trace elements (except iron and
simple potassium) for a couple weeks in combination with running your CO2
such that with a KH of 100ppm your morning pH is around 7.0-7-4. If this
works, I will explain my theory. There are several reasons why brittle stems/
brittle twisted leaves can occur besides CO2. Also, I dont like to run the NO3
above 30 ppm. This is not that hard a problem to resolve. Post pictures and
the macro nutrient levels. Give your readers more to go by. Good luck.
 

colonel

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Nov 25, 2005
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Re: Slow deformed growth, and brittle plants....

Im sorry but that didnt make any sense to me.... at all...
Your additions are probably outstripping your useage since your growth is
limited right now.The GH is rising because of these additions.
what?

Run an airstone at night and raise the nighttime Redox.
Raise the night time redox? what does that mean? and what is the reason behind running an airstone at night?

Also, I would do a
large water change (75%) and not dose trace elements (except iron and
simple potassium) for a couple weeks in combination with running your CO2
such that with a KH of 100ppm your morning pH is around 7.0-7-4.

Why would I do that? seems to me that the plants are going to need the trace elements are they? and by doing a large water change and then not doseing any... I would imange they are not going to be available at all very quickly?

And as far as the substrate.... on the bottom there is a real thin layer of peat, capped with several inches of Shultz aquatic soil..... topped with a real thin layer of pea gravel to help hold it down.... the tank has only been set up for a little less than a year, and there is no precipitated iron oxide on the roots as you have mentioned.... sorry I just didnt follow your post at all, could you please take time to explain what you ment? maybe others know what your talking about..... I couldnt follow... sorry
Matt
 

Cornhusker

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Jan 23, 2005
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Re: Slow deformed growth, and brittle plants....

Colonel,could it be that your tank has soured on you.using that substrate mixture can be a problem in it's self.you may be much better off,(and i know you don't like to hear it),but you may be much better of starting out new,again.use one of the popular substrates in its entirety.in the past few years i've read more about tank problems coming about from using soil.it can be very touchy.very hard to vacum.we all like to change plants and plant arrangements.with one type of substrate, no problem.the change may do you alot of good.a new start can be alot of fun,with what you know about planted tanks now.i have a 55 that has been a pain in the a-- for over a year.took tom's advice and vacumed very good,like starting out like new. added press. co2 over yeast and wow,what a difference.that tank has flourite.now i'm a happy camper and it was a good learning experiance. good luck. regards,cornhusker :) :)
 

colonel

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Nov 25, 2005
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Re: Slow deformed growth, and brittle plants....

Yea that is an idea and one I have thought about.... though is that really the source of the problem? I dont really want to go through all of that work to finish and set up, only to have the same issue because it is something with how I am running the tank, or with my water chemisty. When i first started off I read a lot about putting a thin layer of peat down first as a good source of nutrients.... however now Im not so sure about it? might have been better off just using the aquatic soil, with the pea gravel to hold it down as it tends to be pretty light....
But anyway if others feel this is a possible source of the problem and a good way to go.... I might try it out. I know that the tank would need stripped of plants, rock and wood.... would I have to get all of the fish out also and totally remove the substrate? or would a simple DEEP vacum over say a week? hitting it once, or maybe even twice a day?
To tell you the truth with all I have put into this tank already i simply DO NOT in any way have the money to buy new substrate.... espically something like Flourite... Basically if you really think replacing it totally is important and the cause of things.... really the only thing I could afford would be like cat litter... or something along similar cost for the amount... comerical products are not in the budget at all....
Once again any feed back from others would be helpful... think that the substrate is acutally the source of these problems? or is it something more in how im running the tank? thanks a lot....
Matt
 

colonel

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Nov 25, 2005
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Re: Slow deformed growth, and brittle plants....

You know what I just thought of something that I should maybe clear up real fast because I am not sure if you are aware.... when I said I used Shultz aquatic soil on top of a thin layer of peat. This is not really a soil at all... I am not sure if you are fimilar with it cornhusker... It is actually a clay granular, fullers earth clay I believe.... it is similar to flourite in its physical make up, just cheaper... which Is why I choose it.... but any way then like I said on the very bottem there is peat sprinkled underneath everything but it isnt a very thick layer, maybe .5 to 1 cm at most..... just thought I would add that in because the Shultz sort of sounded like it is ACTUALLY a soil of sorts, which it is not at all....
 

Tom Barr

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Re: Slow deformed growth, and brittle plants....

Matt,

Your tested measurements appear in good shape.
How about plant biomass? Is the tank packed full of weeds?

More light, more CO2, more nutrients.

You should be fine.

But if you do not see growth, suspect the measurements.
I know, but go back and recheck the CO2/NO3 especially.

These tend to get folks in the most trouble, but with the addition of that much KNO3, you should not have any issues even if the tank was packed full of weeds with more light than this.

So it's safe to rule out nutrients or excesses. I've had NO3 up to 80-120ppm range, L cuda did not like it, but does very well above 30ppm.

I'm not sure what night time redox is either, but perhaps higher O2 levels which relates to redox in that range(the water column), all this will do is help till the plants produce enough O2 from good growth, but all you nweed to do to solve that is raise the spray bar a little to produce some current on the surface(slight ripple etc). Aeration is not needed if you do not try and stop the water surface movement, low O2 can kill your, a little CO2 loss is no big deal.

It seems to be something with CO2 based on what you've said.
Sour substrates can be vacuumed in 1/2 sections over a couple of weeks.
Still, not likely to be the issue.

Lighting ballast will skew as willing many electrical devices, the pH meter/pen readings.

The KH reading is likley correct. Try shutting off and on the lighting and watch the pH. Then other devices.

I'd add enough CO2 with surface moevement till the fish act funny, then back off .1-.2pH units.

You can use 1/2 teaspoon of KNO3, no K2SO4 for now or just after the water change only.

Otherwise things seem fine if you work on the CO2.
Error there seems to be the main problem.

Regards,
Tom Barr
 

colonel

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Nov 25, 2005
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Re: Slow deformed growth, and brittle plants....

Thanks a Lot for the reply tom.... I have known for a while that the extra K2SO4 was not needed, how ever just to be sure it was not something nutrient related... that is an easy enough way to rule it out. And as far as the other nutrients, like you mentioned even if the tank was paked with weeds NO3 would likely be sufficient. And I do have quite a few "weeds" to say in there, H. difformis and polysperma and Corymbosa... and also Myriophyllum simulans. Plant biomass isnt extremely dense, but there is a fair amount of plants.
As far as the Ph KH and CO2.... as with you I likely feel the KH is correct.... and as far as PH goes I have been using a Hanna PH pen to monitor that.... and stopped checking right from the tank a while ago because I was getting reading in the mid 5's (originally why I started adding baking soda to raise ph and KH thinking that this was to low of a PH to go)
Well I soon figured out that the lights... filter what ever else may have had affects was messing with the reading that that wasnt right. So I started taking a cup of tank water over to the bath room across the hall... But I still do not know how accurate the readings I am getting are as the reading on the PH pen seems to jump around a lot. And will change often if you touch the meter after it comes to rest at a given number.
So up the CO2 goes... LoL i have played this game before! I know the good way to do it now, last night I knocked it up a tiny bit, and Ill just keep doing it that way over the next few days until I see some stressing or gasping from the fish. I hope that this is possably reason behind this.
I have been thinking for quite some time now that I have pretty much ruled out that it wasnt lack of ferts. going back to 1/2 tsp. KNO3 and 1/4 tsp. KH2SO4, think its safe to say that is still more than enough no3 and po4?
thanks a lot I greatly appriciate it, and since changing over to a canister filter I have always had it with some good surface movement so that isnt an issue, that with turning CO2 off at night I dont think I really need to be running an air stone. Once again I get a little second wind, haha thinking ALRIGHT! this time i KNOW this is the problem, haha just really hope it is for real this time cause im getting really sick and tired of messing with this.... I want to work on aquascapes and the art part of it already ;)
Matt
 

Aquaman

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Mar 20, 2005
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Re: Slow deformed growth, and brittle plants....

Schultz aquatic plant medium is mostly an illite clay which is very good for
storing cations which the mineral picks up from its environment in small quantities. The use as a substrate is more appropriate outdoors where you have external inputs such as wind blown dust and organic matter. This substrate is probably defficient in Ca unless it was calcined in the manufacturing process. It is definitely nowhere equivalent to Flourite in iron content. For a flourite substitute, Turface Pro is probably a better choice for both iron and calcium. Now that I know more about what you have and are adding. I would say you are calcium deficient. Plants will definitely grow twisted if you are calcium limited. Try boosting your KH with powdered CaCO3 instead sodium bicarb.
Redox is short for oxydation-reduction potential. For vascular aquatic plants it is important to transport O2 down to the root zone at night for many complex reasons having to do with nutrient scavenging and use processes. Some plants that do not have leaves at the surface or emergent have trouble if the substrate is too acidic or too low in oxygen.
I recommended nighttime aeration out of personal preference for several reasons and especially because aquariums are not fully analogous to either ponds or streams(2 different situations). First, if you are using a cannister filter which gets changed infrequently(such as an Eheim), as the filter loads it becomes the largest biological oxygen demand on the aquarium system. At night when the plants are no longer using CO2 and producing O2, they become oxygen users along with the fish and the microbes in the filter and substrate. Short of profiling the O2 diurnal cycle every so often, you cannot be sure that you are not depriving your fish and/or your plants of needed O2. Although fish can live through a period of reduced DO, they may not be able to thrive if BOD becomes too high which has ramifications for long term husbandry all other things being equal. Obviously with a light fish load and a spray bar return you are at less risk. Since fish easily double their O2 need while digesting food, I would not recommend feeding at night just before the lights go out and there is no aeration.
Depending on whether you have the cheaper model of the Hannah pH pen or the deluxe one, when the pen ages one year plus, slow or flickering readings are par for the course. You can try cleaning and then calibrating with standard solutions, but if the problem continues, its time for a new meter. Sometimes almost low batteries can also be the problem.
A word about CO2 and O2. The concentration of these dissolved gases is independent. It is possible for both gases to be saturated. Excess CO2 for a given KH/pH will still cause fish death by anesthesia in the presence of saturated DO. It is also possible to have supersaturation of all the gases and fish death by gas embolism. See the concepts of Total Gas Pressure and Partial Gas Pressure.
The explanation for the comment of your additions of nutrients outstripping the useage of those nutrients by the limited growth plants assumes that CO2 is not the limiting factor. Plants with optimized growth use trace, micro, and macro nutrients in relatively fixed ratios(this differs by species of plant and sometimes by biotope). Also some nutrients become inhibitors if their concentration gets too high. Before you mentioned Schultz's, I was shooting in the dark and suggested several ways to allow your plants to readjust. This is one of the reasons that you will see some authors recommend nutrient pulsing techniques. By the way, it is possible for the solubility of a nutrient to not be high enough to be toxic in the water, but yet still become toxic once precipitated into the substrate and taken up by the plant roots. This is especially true of some trace elements. To illustrate, you were adding K, Mg, sulfate, and nitrate but you had brittle stunted plants with limited growth. Since we now know that Ca was the nutrient in short supply within a few days after a water change, your rate of addition of the other nutrients was exceeding the rate of uptake by the slow growing plants. Thus concentrations in the water column were rising. This is why your TDS(Total Dissolved Solids] and indirectly your GH were rising. They were not being removed from the water column by plants growing. Remember, plants are used as filters in environmental science. GH is effectively cation hardness.
Hope this helps.