CO2 Lowers pH???

**teddscau** · 04-26-2011, 11:02 PM

I think I've found out why my fish keep getting sick. Most of my fish prefer a pH under 7, but their pH is over 8. I've been looking into DIY CO2 systems to lower the pH, but I need some advice to avoid pH crashes, too sudden of pH changes, etc. Any tips or thoughts???

**lotus flower** · 04-26-2011, 11:25 PM

It's true that CO2 could lower your pH...you might try running more air into your water through an airstone(s) at first in order to help push off some of the CO2 as gas. Then, you could gradually reduce the amount of air you inject as you see fit, to gradually adjust the pH.

You could also try lowering your temperature in your tank to allow more oxygen to dissolve, but this should also allow more CO2 to dissolve so it may not help at all (solubility is related to the partial pressure of the gas(es)). However, maybe lowering your temperature a few degrees while injecting additional O2 might make the transition more gradual for your fish.

I don't honestly have any experience with CO2 systems, I just know this stuff theoretically. So check to see what others have to say and do a little research before you take my word for it. Best of luck.

**rich311k** · 04-27-2011, 12:02 AM

CO2 is an acid and will lower the PH, it however does not lower dissolved solids which is what a fish would need, not just a lower PH reading. If you want to lower PH use a mix of RO water, or try adding driftwood or peat.

In most cases it is not needed, fish are quite adaptable.

**teddscau** · 04-27-2011, 12:04 AM

Thanks for the reply. I just found out it's not the tap water that's all pH like, but my tank. The pH of the tap is under 7 (stupid pool pH measure chart is sucky), while my tank pH is 8.2!!!!! I have cuttlebone and handpicked rocks in there. Could that be messing up the pH? PS, talk about "stable" pH!

I feel so bad :( I've been trying so hard all this time to figure out why all my fish die prematurely, but I didn't look at the obvious ones first:( I've watched as all my favorite fish died without any apparent reason. I feel like crying. But, let me tell you something, I'm not a careless fish owner. Everyone knows how hard I've been trying to make them better. And I honestly love my fish. I'm not into fish for "something to do", I'm in it for my little buddies. I don't use them as a decoration, I've honestly only wanted them to be as happy and healthy as they can be. Without Dave's comment on my pH, I probably wouldn't have caught it.

So... back to why the pH is so high. Any suggestions? Thanks.

**rich311k** · 04-27-2011, 12:07 AM

The cuttle bone could be doing it. The rocks could as well, depends on what kind of rocks they are.

**teddscau** · 04-27-2011, 12:08 AM

The rocks are "ocean" rocks from PEI. I should probably take them out, soak, and boil them.

**sphingo** · 04-27-2011, 01:36 AM

Put some vinegar on the rocks, if the have any limestone in them they will fizz. Limestone will cause the pH to go up very fast.

**TazManiac** · 04-27-2011, 01:52 AM

My bet would be the cuttle bone. They are quite soft and I reckon it could be slowly dissolving.

**DrNic** · 04-27-2011, 03:04 AM

This chart might help...
http://www.petfish.net/kb/entry/259/

I found it when I was having pH issues in my tank and was also surprised about the lowering of pH leading to a more acidic tank.

**teddscau** · 04-27-2011, 11:31 PM

Thanks for the chart Nic. Thanks for the help others (not going to start copying and pasting user names). I'm going to take out every rock (almost every) and every little chunk of cuttlebone. Why did I have cuttlebone in there? Because I had snails and currently have shrimps in there. Not sure if the cuttlebone was helping them though. None of my shrimps have had problems molting since I put the cuttlebone in though. My ghost shrimp keep having babies! Guess I won't have to replace the dead shrimps. I'd like to report my bamboo shrimp I got February??? are doing great! Nice colour! I don't even feed them! My fish are messy eaters, which allows the bamboo shrimp to filter their fill. The bamboo shrimp also seem to enjoy the delicacies of the gravel (poorly digested food, yum!)

Sorry for getting off topic there. I still wonder why my betta has popeye, he's not in the tank with the unstable pH. He keeps having trouble with his scales too. Probably just came from a poor bloodline. Maybe I should try dried almond leaves...

Anyways, I hope the pH will get better.