pH of fresh saltwater

[alabrew]

Just got a pH meter and on mixing a new batch of saltwater (IO) I noticed that the pH is only 7.8. Shouldn't it be more like 8.2? Anyone else notice this? I don't suppose that it would change the pH of the tank too much because of the volume, just curious.

 

[grav]

Pick one, is it fresh or salt...

kidding

If it is RO / DI water you used your reading could be anywhere... but will have ZERO effect on the tank. There is a long explination about how the tiny few ions that get past the RO/DI shifting the test one way or the other. Try this, add just a TINY bit of PH buffer, and test again. You should see it shift the other way... perhaps to 9.0. Still with a nominal effect on the tank durring the change.