# ADA substrate question



## RichardG (Feb 1, 2009)

I am using the ADA substrate system on a newly planted aquarium and I am having a problem. The substrate seems to lower the ph of my water to dangerous levels. The water I am using starts out at 7.5 to sometimes 8.0 and when I inject co2 it goes down as expected but never goes back up. I am using a co2 controller so then it never puts any more co2 out. I keep adjusting the controller until it has lowered the ph to the low 5's and it still stayes right where it stopped. What am I doing wrong? I know many people have used this substrate with great success but being new to planted aquariums I am confused about my results. Does anyone have any ideas?


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## Bert H (Mar 2, 2004)

I'm not sure I understand your question. 



> The water I am using starts out at 7.5 to sometimes 8.0 and when I inject co2 it goes down as expected but never goes back up.


If you're injecting CO2, the pH will drop, why do you want/expect it to go back up? That's normal. The controller will maintain pH where you set it, so that's correct as well.

If you're using a drop checker, follow the directions for its use, make sure you have kh4 water in it, and don't worry about your pH.

You may have read this already, but if not, you might find it helpful:
http://www.aquatic-plants.org/articles/basics/pages/index.html

HTH.


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## Tex Gal (Nov 1, 2007)

This substrate does lower pH. That is one of the reasons that it's so good for planted tanks. It will reach a level and stay there. Then once you add CO2 it comes down even farther. It's really a little disconcerting the first time you see it. Not to worry as it doesn't bother fish or plants. Everyone thrives. Just acclimate your fish and shrimp ect. like you normally would.

Do not add chemicals to try to raise your pH. That will cause problems. The only issue I have had is trying to keep fancy snails. The pH is too low for their shells. Other than that, shimp and fish do fine.


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## RichardG (Feb 1, 2009)

As I am sure you know the controller has set points,,if your ph never goes back up to a level that makes the solonoid kick on again you have no more co2. This is my problem,,I do have a drop checker and after a day or two of no co2 it shows just that, no co2. So, I adjust it down further to get some co2 into the water. I have adjusted the set points to the point that my ph has gone below 5.0 before it stops and guess what? It never changes and I still get no more co2. If you are telling me that it doesn't matter how low the co2 goes that is fine by me.


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## nfrank (Jan 29, 2005)

the pH of your water is affected by the humic acids released by the aquasoil. That pH is not directly related to the CO2 level. You may also want to re-calibrate your pH probe. If it says 5.0, it may not be exactly correct. pH of 5.0 sounds very very low even for aquasoil.

My tap water is around 7.4. With my aquasoil and with the CO2 off, the water gets to be around around pH=6.5. I set my CO2 so that i bring the pH down to around 5.8-6. I never tried to figure out how that translates to ppm. I probably can make the pH a little lower.


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## RichardG (Feb 1, 2009)

I thank everyone for the information,,I am really trying to understand the chemistry. According to the KH as compaired to ph table that I was refered to my KH is at about 1.7 degrees with a ph of 6.1. The confusing thing is that it seems to stay there and I have gone for days with no futher co2 entering the aquarium via the injection system. So are you saying that as long as the ph is stable and the KH is the same I do have the proper amount of co2 in the water even if the drop checker doesn't seem to show that?


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## nfrank (Jan 29, 2005)

if your substrate is new and still leaching out acid, then the pH of low 6's could be a direct result of the humic acids. You will need make the pH lower with injected CO2 if you want to have enough in the water..... lets say 5.8 to get the amount of CO2 needed. The way i understand the drop checker (i dont have one) is that the liquid in the checker is at KH=4 is in equilibrium with the CO2 in the water. The checker liquid will turn green when the CO2 is at the point of the chart that corresonds to approximately 6.8 and KH=4. Make sure you use distilled water and not tank water for it to be accurate.
I believe one problem with the checkers is that they dont respond very quickly. On the other hand, CO2 levels can change quickly. Also, the CO2 is not going to be at the same concentration throughout the tank. Where it is injected, it will have the highest concentration and in areas of the tank with little water circulation, the CO2 can be less. Also plants are using the CO2, so that causes it to drop. The CO2 will be lower in the middle of a stand of fast growing plants. Stong water circulation will keep CO2 more uniform. 
Here is the bottom line: your drop checker can be reading a different concentration than your pH probe that drives the controller.


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## Quetzalcoatl (Feb 13, 2009)

pH of 5 is NOT unheard of when using Aquasoil and injecting CO2. 
It really depends on too many variants to really say, "yes it is normal" or "no it is not normal".
From my experience, if I use soft water (e.g., RO water), inject CO2, and if the soil is new, then I do get pH of low 5. 
It also depends on how much soil you used and how large your tank is. 
Since this sounds like a brand new tank, Aquasoil is still in the process of releasing all its acid, thus making the water soft. After the soil had its break-in period (several weeks), then your pH should start to stabilize. Again, the exact level it will stabilize depends on too many factors.
Once you are in that state, your pH controller and CO2 injection should start to work again. Basically, while your CO2 is on, your pH will gradually drop until at certain point where your pH controller hits the low setting. After CO2 is off, your pH will gradually rise until at certain point where you pH controller hits the high setting. Then CO2 goes back on... etc...


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## nfrank (Jan 29, 2005)

I agree with Q that my generalization about pH of 5 for aquasoil being very low is incorrect. Not only does it depend on the relative amount of soil to water, but perhaps more importantly to the amount of water exchanges and mineral content. I too have very soft water KH/GH of 1-2. My pH wo CO2 didnt go below 6, but i was doing daily 50% water changes for the first 2 weeks, then every other day for a while. Now 1x/wk. That dilutes those humic acids quite a bit!


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## RichardG (Feb 1, 2009)

OK;

Thanks everyone for the information again. But one final question please? I still have the problem right now while the the soil goes through it's break in period of having no way to get co2 into the water without doing it manualy. Is that what I need to do,,just run the co2 system awhile until the levels are right according to the drop checker or just not worry about the drop checker at this point while the aquarium is going through this break in period? All plants and fish seem to be fine,,

Thanks again


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## Quetzalcoatl (Feb 13, 2009)

I think you answered your own question. What really matters in the end is how well your plants and fish are doing. If they are doing well, that is what you want. Don't get obsessed with getting the numbers the same with what everyone else say. Number is just an indicator and is only relative to your environment. 
When you have time, like on weekends, you should experiment a little. In the morning change your settings so little bit more CO2 will be injected in to your tank. At the end of the day, if you see your plants looking healthier (maybe more oxygen bubbles coming out, etc...) then maybe you want to keep that setting. If you see some fish raising their nose, then you should cut back some CO2. Just don't change anything too quickly.


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