Once again I fail with co2

[edacsac]

Once again I've been fiddling with my co2. I added more plant mass and said plant mass has been growing well, so I upped co2 - to the point of almost gasing my fish, then backed it down to probably too low of a level. Needless to say I have all kinds of algae at this point.

So I finally broke down and bought a drop checker from a fella at the plantedtank. I thought I was good. The first use of the drop checker took about 3 hours to turn green, but the problem I'm having is it never goes back to blue. By the next day it's yellow and the next day is even yellower.

The drop checker kit comes with a bottle of blue solution. First I tried mixing a little with distilled water, but could not read the color, so I now use it straight.

It seems to me that my co2 level does not dissipate at night, but continues to increase up to water change day. The behaviour of my fish seem to indicate this as well. I have my filter outlow creating constant and massive turbulence at the top of the water, yet the drop checker stays yellow all the time, even right before lights on when its had almost 14 hours of no co2.

I am just not doing well with co2.

 

[ceg4048]

edacsac,
If the plants were doing well why did you change the CO2 so soon? The drop checker always takes a few hours to respond to the CO2 level in the tank. Also it takes a few hours for the CO2 to disperse and to saturate the tank water. Normally, you want to turn on the CO2 an hour or two before the lights come on that way there is a stable, high concentration when the light initiates photosynthesis. You can also turn the CO2 off 2 hours before the lights go off. Now, when you turn off the CO2 it doesn't mean that the CO2 in the water suddenly disappears, especially if the tank is tightly covered. Think about an open bottle of coca cola. How long does it take to go flat? The gas has nowhere to go so it simply dissipates slowly overnight, but may not completely evacuate by the next morning.

The second problem is that you don't seem to be using the proper water in the drop checker. Check out this site:

Measuring CO2 levels in a Planted Tank

It discusses the relationship between the pH, the kH and the dissolved CO2 concentration in a sample of water. When CO2 dissolves in water it forms carbonic acid which changes the pH of the water. This relationship is only valid when CO2 is the sole source of acid in that water.

That blue solution that come with the kit? All it does is show you the pH of the water sample. If your water sample is pH 7 or above it stays blue. As the pH of the sample starts to turn green it means the pH is approaching 6. When the sample turns yellow the pH is below 6. Ideally, we want a CO2 concentration of about 30 ppm, and when that happens we want the water sample in the drop checker to be a nice lime green, which if you check the color chart on your drop checker kit means that the pH of that water sample will be about 6.6. Now check that link I gave and look at the bottom of that page. Can you see that in order for the pH to be 6.6 at the same time when the is 30ppm CO2 in the sample the kH of that water sample needs to be exactly 4 kH?

So can you also now see on that chart that if you use distilled water in the drop checker, and lets say the kH of that water is for example, 2, the water will turn green at less than 4 ppm CO2 concentration? At only 10 ppm the drop checker with that water will already be at a pH of 6 and will be yellow. So you wouldn't know the difference between 10 ppm CO2 and 60 ppm CO2 using that water in the drop checker because it would all be yellow.

Likewise, if you used tank water, or even tap water in the drop checker, you have no idea what dissolved acids are in the water to affect the pH of your sample. There may be no acids but the kH of the water may be say, 8. Back to the chart. Can you see that at a kH of 8 the water sample will reach pH 6.6 only when you have 60 ppm of dissolved CO2?http://www.barrreport.com/images/smilies/eek.gif


If you are not using a 4 dkH water sample in your drop checker, or if you are unsure of the chemistry of the water sample you are using in the drop checker you have absolutely no idea how to interpret the colors of the checker and therefore you have no idea whatsoever of your actual CO2 concentration.

Once you have mastered the concept of the drop checker and why it works, CO2 will be much less of a mystery than it is currently, and you will be easily able to regulate to the proper levels. You'll never ever again be able to say "I am just not doing well with co2" .http://www.barrreport.com/images/smilies/biggrin.gif


By the way, 4dkH water is available at online shops. Making it is possible but is a bit of a drag. It's much easier to buy.

Cheers,

 

[ReedFish]

I have a question, or two, too

So, I'm not even sure what a drop checker is, I use the regular drops and test tubes, but if there's a better way, where do I find this stuff? Also, I bought a Milwaukee SMS 122, with the PH controller/monitor and I'm having trouble with it. It reads a much much lower ph than the tank actually has, and therefore has little use as far as regulating CO2. Everyone else I've read about raves about their accuracy, so what am I doing wrong? It seems calibrated, b/c when I put it in a glass of aquarium water, it goes up to the right ph! Please help, anyone....

 

[VaughnH]

http://www.barrreport.com/articles/2661-drop-checkers-co2-indicators-why-how.html

 

[aquabillpers]

I'm sure that eventually you will get your CO2 system working. Everybody does, if they put enough effort and money into it.

But if you get tired of all that, an alternative is the "low tech" approach (or "natural" or "Walstad" approaches). This features a soil substrate, lower light, and usually no nutrient dosing nor CO2. Plants grow well and they don't require the constant attention that the higher tech tanks do.

Tom Barr has written about this and there is a board that is dedicated to it: http://www.aquaticplantcentral.com/forumapc/el-natural/

(Why do I feel like a subversive when I post about this approach?)

Good luck!

Bill

 

[Tom Barr]

Perhaps you/we are subversive

Using low light, high biomass, good current and CO2 should be fairly easy to do.


Regards,
Tom Barr

 

[ReedFish]

I'm totally getting a drop checker, but as far as keeping the system automated, should I put the probe in a spot without current, or away from plants, higher, lower, etc? I'm a little bit upset that I spent all this money on this fancy gadget and it isn't working...

 

[Tom Barr]

Probes of every sort should be placed in higher current regions.

You may use probes as a relative measure of CO2.

Say based on the pH drop checker, you now know a target CO2, you may correlate that information with the pH probe.

KH can change however, and there is a 2 hour lag time with the pH drop checker.
There is also color resolution with respect to your/our eyes(about 0.2pH units if you are good).

One could use a spectrophotometer if they could syringe the solution out of the sealed pH drop checker and place it in the spect to get a pretty accurate reading also.

They are far better than eyeballs

FYI, everyone fails with CO2 and makes a lot more assumptions with this one parameter than any other in the hobby.

This leads me and others to suggest less light, non CO2 methods etc.

But failures are how we learn, trick is not to do the same ones over and over and get too full of one's self to admit you might be overlooking something and blaming the wrong thing.

I've made plenty of mistakes, so I no longer trust myself
I have to double check and verify. We all should.





Regards,
Tom Barr

 

[ReedFish]

Drop Checkers

Ok, so you guys are totally awesome But I have another question-- I bought a Red Sea drop checker, and the instructions said to put aquarium water in it. I have no idea what the actual reagent inside of it is, so I'm not sure if it's measuring CO2 in the air, or if it's measuring CO2 as a function of ph and kh. If it's the former, cool, right? But if it's the latter, should I be using distilled water with a kh of 4? Thanks again, for all your help

 

[ceg4048]

Reedfish,
RedSea are assuming that the only acid in your aquarium water is carbonic and that your aquarium water is 4dkH. I think that most all of the reagents are typically Bromothymol Blue. The reagent doesn't care about the source of the acid or base in the solution it is measuring, it just turns color based on the pH in the solution. As discussed previously the color range will depend on the kH in the sampling water. As long as you use 4dkH water you will have an accurate and more importantly, consistent pH measurement of the sample.

Again, as discussed in previous posts the CO2/pH/kH relationship can only be observed properly if the sampling water has no "contaminants" that would affect the pH reading. That's why using tank water is never a good idea. In fact, if you think about it, why would you even need to buy a drop checker if using tank water were valid? all you would ever need to do would be to measure the pH and kH in your tank and use the chart to determine the CO2. It's precisely because the tank water is unreliable due to dissolved acids or bases that it's use in the chart is invalidated.

Using the 4dkH distilled water in the checker isolates the sample from any contaminants so that you are sure that any pH changes in that sample can only be as a direct result of the CO2 dissolving into that water sample across the little air bubble that separates the checkers water from the tank water. That's the primary reason that the drop ckeckers color change response is so slow. CO2 has to essentially evaporate from the tank water into the little bubble and then dissolve from the air bubble into the drop checker solution. In the morning, after you've turned on the gas, the checker color is only telling you what the CO2 concentration was an hour or two ago. At some point during the day, the CO2 concentration in the tank arrives at, and stabilizes at it's maximum (injection rate minus evaporation and plant consumption). An hour or so after that, there is an equilibrium of CO2 concentration in the tank, in the bubble and in the checker's water sample. This process may take 4 or 5 hours so you have to be patient with the drop checker and with the adjustment of your bubble rate. If you lose your nerve too early because the color isn't changing fast enough you turn up the gas and a few hours later the fish suffer and the checker turns bright yellow. You see the fish suffer and turn down the gas then the plants may suffer. This is the yo-yo effect edacsac and many others experience. This is often coupled with inaccurate color changes due to use of tank water in the checker. Yo-yo(ing) can often induce algae.

You need to use the drop checker systematically and with patience. Give yourself some time like on a weekend when you are home to observe. Use 4 dkH water. Set your initial bubble rate and observe the color changes throughout the day. Find the maximum stable concentration color and note the time of day it occurred. If that color is too blue make a minor adjustment by increasing the bubble rate and leave it there for another day. Note the maximum again and make another minor adjustment if necessary. Remember that most fish can tolerate a limeade green or even into the yellow if you turn off the gas. You will find that with a covered tank you can turn the gas off 2 or 3 hours before lights off. In the morning the checker may still show in the green. No problem, turn on the gas an hour or two before lights on. If you are patient and methodical, you'll find that you'll consume a lot less gas because your timing will be right. It's much more important that your concentration is up in the morning when lights first go on. In the afternoon the concentration has maxed out and the plants are on cruise control. Nearing the end of the day you can throttle back but there is still plenty of gas dissolved and the plants are beginning to lower their consumption.

If you avoid being mesmerized by the drop checker color changes you will be in a better position to determine the profile of concentration changes that occur and it will enable you to respond methodically instead of impulsively.

Cheers,

 

[ReedFish]

Thanks for all of your help!

Thanks, all of you, for all of your help. You guys are awesome

 

[FacePlanted]

Those were really well articulated posts ceg4048. I understand the whole process, but couldnt put it into words that fully explained the process as well as you did.

-mike b-

 

[ceg4048]

Thanks mike. Articulation borne of pain, I assure you.http://www.barrreport.com/images/smilies/tongue.gif

 

[edacsac]

Thanks for all the replies before things changed direction! I bought some 5dkh water and have been running at green for a few days now. Never goes back to blue, just stays green. I have every brand of algae avaliable; green stringy things, beard, black, fuzzy. I have an area that I recently planted hairgrass somewhat dense, and there is green and black algae covering the hairgrass all the way down to the substrate. I can even imagine how I'd clean it out. Biggest mess I've had since I started this tank. I've cut back on ferts a bit as far as amounts. I don't want to do do a blackout. I Think I'm going to patiently trim the algae off and hope that helps. I still don't think the drop checker is reading true. Funny thing is there was a time I had no algae except for reoccuring cyano.

 

[VaughnH]

Edacsac, I'm kind of lost here. How much light do you have? How large a tank? And, what is your fertilizing routine? High CO2 alone does no good. Plants have to have adequate N,P,K, trace elements, carbon source, light intensity, water circulation, water cleanliness, substrate cleanliness, etc. And, the more light you have, the more important it becomes that all of the above be done near perfectly and consistently. Otherwise you become an expert algae grower.

 

[edacsac]

Ya, I know. Since I've had my tank I've had a few weeks of "no algae" before the cyano set in. Once I corrected the cyano with anibiotics, it's been hell ever since.

10g tank, 36 watts AHSupply lighting, I do the recommended EI dosing fit for a 10 gallon and do 1 water change per week of at least 50%. I think I doubled my K? for awhile while trying to fight cyano, I went from 1/8tsp to 1/4tsp, but now I'm back down to 1/8. I stir up the areas of substrate I can when doing a water change and try to remove some of the larger particals from my filter about every 3 weeks, although when I do that and turn the filter back on, I get so much crap in my tank that I have to do two more water changes afterwards.

The front right section of my tank is the worst. I have remnants of hc, plenty of dwarf hairgrass, and I think that area is the "trap" area from my circulation. There is an incredable amount of algae of all kinds in that area. I added the smalled pump I could find (minijet 404 I think) to add some flow to that area, but it was still to much for the 10 gallon tank. There is algae everywhere though.

I just recently trimmed about 30% of the overall mass because it was so algae laden, but plant growth is relatively non-existant since then. The algae is growing wickedly though.

For awhile things where getting better after added some wisteria. The wisteria was growing fast and algae was slow, but then I adjusted the co2 to accomodate the huge increase in plant mass, and it's been downhill since then.

 

[Tom Barr]

Well, 36w of Pc A&H light is extremely strong lighting.

Add DIY CO2 to this 10 gallon.........

Good recipe for problems.

I would add 1/2 that light or raise the light up 6", and use a good/better method to diffuser the CO2.

This is not a nutrient issue so much, BGA pops up when the NO3 drops but you need to clean the tank etc as well.

Algae is not just about nutrients.


Regards,
Tom Barr

 

[edacsac]

I have pressurized co2 and a rex style reactor. I have drop checker using 5dkh water that stays green even when the co2 is off. My riccia pearls at night in the pitch black. In fact, the riccia never stops pearling when I think I have almost ediquite co2. I've done the basic EI, I've doubled it I've reduced it by half and have come full circle back to the basic recommendations for a 10gal tank. I'm just lost. The algae is so bad in spots that I'd almost have to rip everything out to clean it. I know it's still a co2 problem as my drop checker is useless. How can it stay green when there has been no co2 for over 14 hours? BGA is gone now, its all the other hair and stringy algaes. Not just one, but all of them.

 

[edacsac]

I'm starting to think that I just don't have the skill to run a planted tank. When I added the rex style reactor is when everything became really good for awhile, but then I had to deal with bga. Once the bga is gone I'm back to where I was when I had poor diffusion. When the co2 is up, everything pearls and there is bubbles everywhere. The plants don't care though and the algae has a field day. My only thought at this point is to reduce the nutrients to starve the algae.

I've also been trying to breed cherry shrimp in a seperate tank to help with the algae to no avail, and I bought two oto's to help eat the algae, but they don't touch it.

 

[VaughnH]

First, you have to stop thinking that algae are caused by too much of any fertilizer. It isn't. The blue green algae usually points to not dosing enough NO3. So, cutting back on nitrate dosing will only make it worse.

The drop checker does work. It takes 2+ hours to reach equilibrium with the CO2 in the tank, so if things are changing, the drop checker color will always lag behind. When you shut off the CO2 the amount of CO2 in the water begins to drop, but not rapidly, unless you have lots of surface movement, including rippling. So, the drop checker will stay green or blue green until the CO2 comes on again. Mine never gets any more blue than a blue green, and my CO2 is off about 12 hours a night. I start the CO2 about 4 hours before the lights come on, so it is green when the lights come on. But, this is not a precision measuring device. Its accuracy depends on how well you can "read" the color and how accurately your standard KH solution is made. The value it gives you may not be what is in the majority of the water, unless you have good water circulation throughout the tank. In mine I have the filter/reactor outlet spray bar across the upper back of the tank, so it slightly ripples the surface, with the filter return down in the rear corner near the substrate. Then I added a powerhead at the back pointed along the back wall to give a circular flow around the walls of the tank. All of my plants wave in the current. I still have circulation problems when I neglect to prune the excessive stem plant growth. (A job I face this afternoon.)