# Soil and CO2 regulators



## Larsvb (14 Apr 2011)

Hi Guys, this could either go in Substrates or in CO2. 

Currently I have normal gravel in my tank with a nice JBL CO2 system that continuesly measures the PH. Using CO2 I am bringing down the PH level from 7.5 to 6.9. This works quite well. 

Now because I have seen the effect of a good soil (like Colombo Florabase) on plants I'd like to swap my gravel for this soil. Now, as this influences PH to go to 6.5 how will this affect my PH controller? Do I need to give it a different setting. Any thoughts?


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## George Farmer (14 Apr 2011)

Personally I wouldn't bother using the pH controller and just have CO2 come on an hour or two before the lights, and off an hour before lights turn off.

Measure the CO2 using a 4dKH drop checker.  http://www.ukaps.org/drop-checker.htm

I understand that pH controllers can be useful, but actually they are probably not as reliable as the method outlined above, no matter your substrate type.

All the best,
George


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## George Farmer (14 Apr 2011)

How rude of me!  Welcome to UKAPS, by the way!    

Please consider introducing yourself over here - viewforum.php?f=48


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## Larsvb (14 Apr 2011)

Hi George, thanks very much, I always enjoy your articels in PFKmag.

I have both a PH controller and a drop checker and they tell me thesame really, meaning that I see it become blue when the PH rises and yellow when it lowers. I am just wondering if the drop checker will turn green by itself when using a PH-lowering soil. Is the reagens in the drop checker measuring PH or CO2 level?


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## ceg4048 (14 Apr 2011)

Hi,
 Dropcheckers, when used correctly can only indicate the Carbonic acid associated with the CO2 dissolved in the water. They cannot read anything else. A pH controller probe on the other hand is easily fooled by any acid or base in the water. There are many acids and bases in the tank.

This is one of several reasons that we suggest to first use only the monitoring function of the controller until you understand how to compensate.

Cheers,


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## Larsvb (26 Apr 2011)

just for completeness of this thread here are my findings.

Normal water PH is 7.6 in this area. Normally I'd set my regulator to PH 6.9 and this gives enough CO2 in the water to make the dropchecker go beautifully green. 

With Ebi Gold Shrimp substrate the PH went from 7.6 to 6.5 in a day and remained steady. The drop checker gave me a blue color. I have set the regulator to 6.2 and this gives enouch CO2 to the water to again make the dropchecker go green. 

Over time the substrate will lose its capability of lowering the PH so the dropcheckers should indicate this when the water gets too much CO2 and will go yellow.

Crystal Reds are doing great.


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## bigmatt (26 Apr 2011)

Hi there and welcome!
I've never used pH controllers (could never afford them!) but from reading on here the argument against them could probably be summarised liike this (for i am bear of very little brain and long words confuse me...  )
...we are aiming for a constant concentration of CO2 in the water to aid plant growth, and failure to provide this constant level essentially "confuses" the plant's chemistry, leading to BBA and poor growth.  pH controllers respond to changes in pH, rather than the amount of CO2 in the system - in an empty tank filled with RO water where CO2 is the ONLY variable then use of a pH controller will  indeed provide a constant level of CO2.  However, in a planted tank with plants, fish, substrate, hardscape and a million other variables the pH controller cannot determine what is causing the ups and downs in pH, and thus can constatntly be switching the co2 on and off inappropriately - leading to the afore mentioned problems with BBA and poor growth.  
Apologies if i'm telling you things you already know! Hope this helps!
Matt


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