Water Change

[WaterBaby]

I have a 10 gallon, recently set-up, cycled tank. This will be my first water change.

The pH in this tank is 7.6-7.8. I do not know why. The pH out of my tap water this week (it does seem to change all the time) is 7.0-7.2 (which is preferred).

Should I adjust this replacement water to a higher pH, or do I just add it as is? I will be doing a 3 gallon change. Or... should I leave it at 7.0-7.2 and do the water change gradually throughout the day?

Any Clues

 

[JSchmidt]

One common reason for tank water to be higher in pH than tap water is that tap water often contains dissolved carbon dioxide, which is acidic in solution. As the CO2 offgases, the pH rises some. (You can see if this is happening by taking a sample of tap water, letting it sit out overnight, giving the CO2 a chance to escape, then measuring pH.)

Another reason pH can rise is the presence of calcareous rocks or gravel (limestone, seashells, crush coral). As these dissolve, pH will rise.

If the difference between tap water (aged overnight) and your tank remains, you can simply do smaller, more frequent water changes. You are much better off leaving pH modification alone. It is very difficult to do in any sort of stable fashion, and the bouncing pH that results is stressful to the fish. Your tap and tank water, as you report them now, aren't terribly different and most fish would be OK in at either pH level. Just limit changes to 25% and you should be fine.

Good luck,
Jim

 

[momopoms]

I have been (perhaps ignorantly) changing my water all at once, ie; just replacing the water at one time rather than gradually, is this bad? I know my pH is probably different fresh from the tap, but the fish seem to be doing well, and I do NOT want to even start the pH adjustment roller coaster.

Any way, from what I can gather, (this board being my main research resource) your pH is not bad, and the lower pH being ideal would it not bring the average pH down just a bit from where it is right now.

 

[WaterBaby]

Guess not. Just checked to make sure......Still at 7.6-7.8 (after the 7.0 water change this morning).