Buffers in my water

[BeefyG]

So my water straight from the tap reads 7.4 ph. That evening it reads 8.0 and by the next day it reads 8.2. It seems to stabilize out at 8.2. I'm pretty sure this killed my discus I was trying to grow out long time ago and I used to mysteriously lose fish such as gouramis and tetras. I currently fill a 75 gallon tank with water and run a filter on it for a day or so before using it for a water change. This is getting to be a huge pain although I managed to rig a pond pump to pump the water back out.

I'm cutting down to two freshwater tanks. A troph tank and a pretty tank for my daughter. The pretty tank will have angels, gouramis, tetras, and other random fish. It will probably still need the conditioned water but what about trophs? Are they sensitive to ph swings? Is there something easier I can be doing?

I may also keep my peacocks which would make three tanks? Are malawis any different?

[nacra99]

This is very common. 8.2 sounds like an average number for the greater houston area, and the pH tends to indicate a higher KH which tells me that your water is most probably quite well buffered already.

Water out of the tap contains a lot of dissolved carbon dioxide CO2. The chemical reaction that takes place is represented by the equation:
CO2 + Water <--> Carbonic Acid.
That is why water coming out of the tap tends to be acidic.
If you let the water sit such that the CO2 degasses and leaves water, according to the equation above, the Carbonic Acid will break down and the pH will rise.
Many discus keepers will tell you to store the water in a barrel and agitate with either a pump or an airstone overnight. The agitation will de-gas the water of CO2 while at the same time throughly mixing up your Prime or whatever de-chlorinater and help remove the chlorine.

I would run a strong airstone in your storage tank either in place of or together with your filter for 24 hrs before doing your waterchange. That would give the pH plenty of time to stabilize.

[wesleydnunder]

This is very common. 8.2 sounds like an average number for the greater houston area, and the pH tends to indicate a higher KH which tells me that your water is most probably quite well buffered already.

Water out of the tap contains a lot of dissolved carbon dioxide CO2. The chemical reaction that takes place is represented by the equation:
CO2 + Water <--> Carbonic Acid.
That is why water coming out of the tap tends to be acidic.
If you let the water sit such that the CO2 degasses and leaves water, according to the equation above, the Carbonic Acid will break down and the pH will rise.
Many discus keepers will tell you to store the water in a barrel and agitate with either a pump or an airstone overnight. The agitation will de-gas the water of CO2 while at the same time throughly mixing up your Prime or whatever de-chlorinater and help remove the chlorine.

I would run a strong airstone in your storage tank either in place of or together with your filter for 24 hrs before doing your waterchange. That would give the pH plenty of time to stabilize.

+1
Well said, nacra

Mark

[BeefyG]

So what you're saying is... there's no easy way around a PH swing straight from the tap? I'm guessing different water sources have different levels of dissolved CO2 then right? I know of some people who fill their tanks straight from the tap and have great success.