Plant Only tank question

[creighton]

I have a 20 gal with 55w 6700K AH supply lights and injected co2 with Eco-complete substrate. I'm just keeping fast growing stem plants along with microsword and hairgrass. I'm dosing adding NPK 3 times a week at N=30ppm P=2ppm K=25ppm and CSM+B with Fe at .5ppm. No fish only plants.

My question is about the co2. I don't have a reactor I just run it straight into the in take of my fluval canister. I have the bubbles coming from the regulator going at about 4-5 bps. The filter burps co2 every so often but I think I have sufficient amount of co2 dissolving into the water. Assuming that I do have at least 30ppm or possibly more of co2. Could too much co2 cause algae? I'm having a problem with BGA. It's invading the microsword the worst.

thanks

 

[VaughnH]

Blue green algae is usually a sign of low nitrate concentration and high light intensity. I suspect your plants are growing rapidly with that much light and plenty of CO2, so that may mean you need to dose more nitrate and phosphate. You could try increasing all dosing to 1 1/2 X the EI amounts for a few weeks to see if that does any good.

 

[Tom Barr]

You can run pretty juicy, as long as plants are non limited, whether you have 30 or 40 or 60 ppm of CO2 will not matter much, still, have a good sized filter and current, do large water changes often etc

Regards,
Tom Barr

 

[creighton]

Thanks! I'll try smashing up the nutrient levels.

So another question... I have the ability to run one more 55w 6700K. I've tried it before and had explosive growth, but sometimes explosive algae. I don't really need it, but I bought it and its just sitting there all lonely and cold...

 

[Carissa]

If you already have an algae problem more light will = more algae for sure.....once you get over 3 - 4 wpg max another light usually just turns into an algae feeding device....especially bga in my experience...

 

[aquabillpers]

Blue green algae is usually a sign of low nitrate concentration and high light intensity. I suspect your plants are growing rapidly with that much light and plenty of CO2, so that may mean you need to dose more nitrate and phosphate. You could try increasing all dosing to 1 1/2 X the EI amounts for a few weeks to see if that does any good.

I have non-injected-CO2, 2 WPG tanks with soil substrates. When I set up a new tank, half the time I get a BGA outbreak in the first 3 weeks, It is easily controlled. Nitrates are always where they should be.

I think in that environment BGA occurs because the plants take a while to start using the available nutrients, while the BGA is always there, waiting.

Bill

 

[Tom Barr]

Careful with light, patience is a virtue, let things grow slowly, things that happen fast in tanks= generally bad.

Regards,
Tom Barr

 

[Carissa]

Couldn't it be excessive ammonia leaching from the soil causing the bga outbreaks? Then once the plants get going, they start sucking it up and it goes away.

 

[creighton]

Possibly. The Eco-Complete has been in use for a year or so. The plants are doing well since in increased the nutrient levels to 1 1/2 the EI levels. Its kinda scary looking at the bubble counter. If it had any fauna they would surely be dead. I kinda want to add some RCS just so something would be moving in there, but I'm weary to do so .

 

[creighton]

I have Stargrass, Didiplis diandra, R. Macrandra, P. Stellatus narrow leaf, and needle leaf ludwigia. The needle leaf ludwigia is not growing nearly as fast as the rest of the stem plants. In fact, its barely growing at all. I upped the nutrients so I don't think I have a difficiency and CO2 is off the charts. Could it be that the Needle leaf ludwigia is being out competed for the nutrients it needs? One thing about the P. Stellatus and N.L. Ludwigia is that they are much shorter than the Stargrass, D. Diandra, and R. Macrandra, but they are still getting adequate light.

 

[Carissa]

Sorry, I was talking about aquabillpers tanks...but if there is a source of ammonia in your tank it's worth considering that.

 

[creighton]

Here's an update:

I had kind of a meltdown with most all my stem plants. So... I salvaged what I could from the tops. I threw in a little fresh manz wood and tied some ferns and mosses to it.

I have been adding 30ppm N, 25ppm K, and 3ppm P. Also dosing .5ppm Fe using CSM+B. All on EI schedule.

I still have a real BGA problem as well as diatoms on the glass. I've been doing 2Xweek water changes sucking up as much as I can. Adding appropriate amounts of ferts after. I just did one tonight and things kinda went haywire with the temp. The tanks is a cool 95 degrees right now. I hope the temp will be back down by morning.

Any suggustions?

thanks,
C-Dizzle Fo Shizzle

 

[ceg4048]

Hi creighton,
It's better if we start at the top because it appears you made some assumptions about your dosing that are perhaps incorrect. It's also not really clear how much of each item is being dosed unless we know exactly how many mg or teaspoons of powder per dose you are applying. Quoting a ppm addition is ambiguous.

In your original post you mentioned that you were certain that you had sufficient CO2, but why? How are you measuring the CO2? Are you using a drop checker with 4dkh water and is the color light green to yellow? Is the CO2 running 24/7 or is it turned off at night? If it's turned off at night, how soon prior to lights on is the gas turned on? Meltdown is often an indication of poor CO2 so your "certainty of adequate CO2" needs to be based on stringent criteria.

Too much CO2 does not cause algae but if your CO2 concentration varies wildly then yes it can induce algae, most notably BBA. Is your CO2 pressurized or DIY? DIY is notorious for delivering unstable CO2.

If you are dosing dry powders, then a 20 USG tank ought to be getting at least 3/16 teaspoon KNO3 and 1/16 teaspoon KH2PO4 3X per week. If you have 55W T5 with reflectors over a 20G then you have a LOT of light and you can easily double these dosing numbers. As hoppy pointed out, BGA does not lie. If it appears, then it is telling you in no uncertain terms that the tank is not getting enough KNO3, exclamation point. Melting can also be exacerbated by insufficient KNO3.

High temperaures also do not help. You should definitely solve that problem and you might also want to consider shortening your photo period for now to help in the battle. 8-9 hours would be good for the moment until you sort everything out.

Cheers,

 

[creighton]

Here's the setup:

20 gallong High. 55watts CF 6700K AH supply blubs and reflectors. Eco-Complete substrate. I use pressurized CO2.

Dosing is as follows:

I use 4 seperate solutions for each nutrient.

Stock Solutions:
N= 100g KNO3/L H20
P= 50g KH2PO4/L H2O
K= 42.9g K2SO4/L H2O
Trace= 50g CSM+B/L H2O

Adding 37mls of N solution gives me 30ppm of N. To reach 25ppm of K I add 15.5 mls of the K solution. And to get 3ppm PO4 I add 6.5mls of the P solution. I do this Tuesday, Thursday, and Sunday nights. I add the NPK after the waterchange of sunday night.

For Trace I add 12mls of the CSM+B solution to achive a .5ppm concentration of Fe.

As for CO2 its coming into the filter intake. I turn it on 45min before lights are on, and it goes off 30min before lights out. The bubble counter is running at 6-7bps. The plants are pearling at about midway through the photoperiod.

The photoperiod is 10Hrs right now. I'll cut that to 8 right now.

As for the stupid hight temp. I didn't notice that my cold water pressure slacked off and basically filled the tank with hot water on accident. The temp has gone down to 85 degrees, and should be around 78 by this afternoon. The lights haven't been on the at all until this morning with the elevated temp.

I tried adding 1 1/2 my current fert regimine for about a week, but it didn't seem to do much to the algae so I just kept using the same ppms . I'd listen to you guys before I trusted myself though.

What do you think I should do? I'll go ahead and ramp up the NO3 to 50ppm and cut the photoperiod.

I also just added some fresh Manz wood. Rocks are holding it down. Its growing some white fungus or something on it. Maybe it could be decaying and elevating the levels of ammonia and causing the algae? But I had algae before the wood so that dosen't really make sense.

thanks,
Creighton

 

[Tom Barr]

Colder temps= less growth, higher temps= faster growth.
Another comment as far as algae: higher temps induce many species to bloom.
Coooler temps, not nearly as much.

So stable cooler temps work best.
You can reduce the growth rate between a tank at 83F and a tank at 70F by a factor 2X.

So the tank with 83F might need 30ppm of CO2, whereas the cooler tank will only need 15 ppm etc.

Temp is a big forgotten factor for many folks.

I see wide seasonal changes due to climate I live in, I rarely use heaters except for specific cases.

I think the dosing routine you have is pretty rich, I'd cut that by 1/3, so 20ppm NO3, 2 ppm of PO4 etc............

Unless the tank is really going to town and really full of plants..........it's unlikely you need that much.

20-25ppm NO3/2-3ppm is the point where you no longer see more growth under controlled conditions that are non limiting.
If you maintain that, or close, then you should be fine there.


Regards,
Tom Barr

 

[creighton]

Tom,
Okay. I was originally doing going with a 20ppm NO3 with 2ppm PO4 but I kept the K around 25ppm. Is that too high or could I lower it some? Um...I guess I'll see what happens. Should I do a black out or something?

thanks,
Creighton

 

[Tom Barr]

I rarely do a blackout unless I have a friend who's neglected things and has a really out of hand issue.

I just pick at the algae a lot, keep the conditions at prime levels, do many water changes, dose there after, Add Excel, run a micron filter, UV etc, clean filter good, prune the algae away etc

Like a nice good pruning, it can take some time to do this, however, the labor is rewarded if you can stop new algae growth.

Then you can beat any algae.
And that addresses the root cause and allows you to have far less issues when dealing with the algae that's there.

So that's always the first order of business.
Problem is, folks just read add KNO3, PO4, etc, they do not carefully consider light, temp, routine maintenance/cleaning filters, and CO2 especially.

As much as some want to claim, without support I might add, that it's all about nutrient balance, that's merely only a small fraction of what is going on, I and many folks assume folks are competent enough to do weekly water changes, clean their filters etc.

While many preach that, or testing etc, we are all human and do not always practice what we preach
Now, having said that, I can go back and see if the temp was the issue and how it can influence growth, or CO2 uptake etc, or if cleaning the filter or current are really factors.

These having nothing to do directly with nutrients really(but slows or increases their uptake), but can certainly lead to algae issues.

Then the picture of what happens and why becomes a lot more clear.

So I'd work more on good filter cleaning, getting all the dirt out of the tank, pruning, do 2-3x a week water changes, add Excel daily for a week or two, add ferts after each water change, prune the algae and plants, add more herbivores etc and perhaps lower temp if the fish are okay with that.


Regards,
Tom Barr

 

[creighton]

Okay... So this morning before lights on I did a 95% water change. I tried to suck up as much algae as possible but I still missed a few spots of BGA. I lowered the temp to 60 degrees (there's no fish or inverts in the tank, but I think RCS could handle/possibly enjoy it). I added 20ppm N, 2ppm P, and 25ppm K plus .5ppm Fe. CO2 is still crankin'.

I also cleaned my fluval 204 filter. I just used some warm de-chlorinated water and rinsed everything,and squeezed out the sponges. I added two bags of activated carbon to some ceramic tubes that were the only thing in the filter.

My weekly WC's are done on Sunday, but I think I'll wait till monday and do another WC.

Will the fresh activated carbon suck up some nutrients? I've heard Amano say something to that affect.

thanks,
Creighton

 

[creighton]

Okay. So the BGA is still coming back. I recently looked at my city water report more closely. I had been testing my GH and KH with a AquariumPharm. test kit. The GH read somewhere along 13 degrees and the KH was around 6-8 KH. The water report said the following:

Mg: 3.62-4.80 (it doesn't say the units, but I think it's mg/L)

Ca: 15.4-21.7 mg/L

Total Hardness: 30-96 mg/L

TDS: 70-250 mg/L

I haven't been adding Mg until about 3 days ago when I realized it was so low. I don't have the means right now to add Ca right now but I can get it soon. Is the Ca ppm in an acceptable range?

I haven't been able to beat the algae, so I'm still looking for the root cause.

Any ideas?

thanks,
Creighton Tynes