Buffers and a planted tank

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Digitalgerl

Aquarium Advice Regular
Joined
Jul 27, 2007
Messages
99
Hello,
I have an established 40 gal planted tank. I use CO2 (tank) with a diffuser and dose regularly.
I will be using Eco complete in this tank in the near future. I have a beautlful Texas holy rock that I would like to place in this tank. This rock does have natual buffering properties.
If I know what it takes regarding CO2 to keep my plants healty would it matter if I can no longer take a true measurment due to the buffering?
Would my plants still be able to absorb the CO2 and nutrients?
My pH is kept at 7, out of the tap (after sitting) the tap pH is 8. Nitrates stay at aprox 10-15.
 
As long as the holy rock doesn't break the KH / pH relationship, you'll still be able to measure your CO2 levels as normal. It depends on what type of buffer it's releasing into the water.

Either way, I'd recommend picking up a drop checker and some reference solution. This will give you a quick double check of your CO2 levels at a glance without worry that there is something in your water throwing off the calculations. This way if something goes wrong with your CO2 setup, you have a better chance of catching it early.

It sounds like your water is liquid rock to start with. I'd have less concerns about measuring your CO2, and more concerns that the rock may push the hardness to levels which may be too much for your plants. I would be prepared to pull the rock, just in case. It really depends on how much the rock leaches and buffers the water.
 
Texas Holey Rock leaches calcium carbonate into the water as it's a type of calcified limestone.
My water hardness is (gH) medium and I have kept my kH at 4-5. Tap water is consistantly 3. I use small amounts of baking soda after some water changes to keep it at 4-5.
The rock will supposedly keep the pH around 7.6, more than I wanted but still ok for my fish. I am just wondering if the limestone would cause any ill effects to all of my plants- or hinder their uptake of nutrients and CO2???
http://www.cichlid-forum.com/articles/tx_holey_rock.php
 
While I'm not 100% certain, it sounds like that rock should be perfectly safe. If it only raises the KH enough to push the pH to 7.6 you plants should be fine. Since Calcium is a plant nutrient and people keep plants in relatively hard conditions all the time, neither should be detrimental to your plants. As long as you aren't trying to keep species that require softwater, which I doubt given your current parameters, they shouldn't have any problem adapting.

If you're still concerned, you could always add the rock slowly and keep an eye on both the parameters and your plants. Add a few more each week as long as you don't see any adverse affects.
 
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