co2 and PH question

BrooklynAngel

BrooklynAngel

AC Members
Jan 25, 2007
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Manhattan, NY
Should I continue to fight the PH drop from my CO2 or just give in? Is it possible to overdose on PH 7 buffer? Will it form too many salts and kill the plants? Co2 is 10 and ph went from 7 to 6.4. I brought it up to 6.6 or 6.8 depending on the day.
 
Why are you fighting it? Many plants and fish prefer acidic water.

As for the buffer you are just throwing money away, as the CO2 will continually outbalance it, and bring it down. Now, you could use a constant source of buffer, like Onyx sand which would bring up your KH and GH, and your pH accordingly.

-Jared
 
Buy a drop checker to make sure you're injecting around 20-30ppm of CO2, that way you know you won't overdose on CO2 and you can forget about the pH and kH. You can find them on eBay for pretty cheap.
 
A bigger concern in changes in TDS (total dissolved solids). Keeping those constant is far more important. Adding too many extra "buffer" materials could actually be worse. And many "buffer" products are phosphate based which could just lead to other issues.
 
jmorris said:
Why are you fighting it? Many plants and fish prefer acidic water.

As for the buffer you are just throwing money away, as the CO2 will continually outbalance it, and bring it down. Now, you could use a constant source of buffer, like Onyx sand which would bring up your KH and GH, and your pH accordingly.

-Jared
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Appropriate ammounts of crushed coral,or other marine substrates will buffer when enough is added.I never use additives like that anyway,ads to the T.D.S and is unnatural.Go with a substrate.Since you are needing your substrate to plant in,i suggest putting it in nylon mesh bags in the back out of sight,and not adding it to your planting medium.
 
BrooklynAngel said:
Should I continue to fight the PH drop from my CO2 or just give in? Is it possible to overdose on PH 7 buffer? Will it form too many salts and kill the plants? Co2 is 10 and ph went from 7 to 6.4. I brought it up to 6.6 or 6.8 depending on the day.
Click to expand...

A gross misunderstanding of water chemistry and the effects of CO2. Also a anal fixation on pH.

CO2 is going to lower pH. That is one of the effect of CO2. Now the thing that most people have a very hard time understanding even when it is explained to them in very simple terms is that pH changes caused by the addition of CO2 DO NOT HARM FISH!!!

To understand why that is you also have to know some basic water chemistry. Normally when one raises pH you add KH. To lower pH you remove KH. Now remember this is in water where CO2 is not being added. When you add CO2 you leave the KH alone. So while the pH is lowering the basic water chemistry is not.

As has been pointed out trying to maintain some "magic" pH through the use of over priced chemical buffers is a losing game. Whenever you add the buffers you are also raising the TDS (total dissolved solids). And many times the pH will rebound due to the buffers in the water.

If you feel you must raise the pH/KH/GH then do so with the appropriate product.

Baking soda will raise KH and pH. It's cheap and it doesn't take a lot.

There are several ways to raise GH. Basically you need to add calcium and magnesium.
 
^ Basically, Yup.

To augment the argument against doing buffer additions - Once you do manage to get pH where you think it ought to be, what happens when you do a PWC? Unless you match the TDS, GH, KH & pH of the incoming water, you're going to throw the whole system out of balance, which stresses the fish a lot more than the initial pH swings you were initially worried about ever would have.

From week to week, most well & sity water systems deliver a fairly consistent product. This is a good thing. When you do a PWC and add water that's pretty similar to what you're taking out, all the fish will notice is that things are cleaner. There may be a slight shift in pH as a result of the nitrates, dissolved components of humus and fish waste that you aren't replacing, but you should still be fairly close on GH & KH (with no effort).
 
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