Got a Ph question. I have slowly and gradually added sodium bicarbonate to my water and the KH in now solidly over 100 and the Ph is a solid 8.3. Although my Ph is now steady I am a bit uncomfortable with this level as it puts my fish at risk should an ammonia spike occur. I am wondering now that the KH has been stabilized is it possible to lower the Ph with sodium bisulfate and still maintain the good KH levels? I'd like to run a lower Pg but also don't want to be adding a bunch of chemicals that do nothing but work against each other.
No, sodium bisulfate will
not help you.
It will lower the pH, but this change will only be temporary.
Lowering a water's pH is not as simple as folk make it out to be. Some folk have a very easy time while it is more difficult and costly for others.
You must understand alkalinity. Alkalinity is the measure of water's ability to resist changes to acid. A "buffer", in our context, is most often referring to the alkalinity. The marketing shorthand nomenclature slang for alkalinity is "KH", which "KH" has an entirely different meaning except it mostly relates to alkalinity. Personally, I prefer the term alkalinity rather than "KH" unless I want to be lazy. Alkaline and alkalinity is not the same. Alkaline is describing the water's pH when it is above 7.0. Alkalinity is describing the measurement of the water's ability to resist changes to acid.
To better understand how, a water "buffer", or alkalinity, function, then think of a mattress pad. When you jump on the mattress pad, the pad slightly lifts you back up due to the springs in the pad. The springs act like how the buffer functions. Each time you aggressively jump on the mattress pad then the springs get worn out and don't lift you up so much. The mattress pad is the "water", the pad's springs are the "buffer", and the jumping is the acid. Thus, as you continue to aggressively jump on the mattress pad (that is adding "acid" to the water) on the springs (or "buffer"), then the jumping (or "acid") eventually wears out, or depletes, the springs (or "buffer"); so, then, you eventually have to add more springs (or "buffer").
This explains why folk experience the occurrence of "pH jumping" whenever trying to lower water's pH. Lets say your water's pH is 8.4. When you add an acid, such as sodium bisulfate, the water's pH will absolutely drop to say 7.8 pH. However, if the water's alkalinity is high, then after some agitation and a few hours of allowing the acid to dissolve into the water, then the pH jumps back up to 8.4 pH. This becomes extremely aggravating to folk when they don't understand why this is happening. However, if your source water's alkalinity is low, then the degree of this pH jumping is reduced or not even noticeable.
