Can pH change from conentration?

[Neophyte]

I have had a few tanks for years before discus arrived. They don not have tight fitting lids so there is considerable evaporation which I said took the place of a humidifier. But recently (DUH!) it dawned on me that I should have been topping of the tank with R/O or DI water instead of tap water as the minerals don't evaporate, just the pure water. So, unwittingly I have been making the water harder and harder when, in fact, my water is very hard right from the tap.

My question is this...how does that affect my pH? Does pH change from concentration?

[ronrca]

Take a browse thru the following link. There are a lot of links explaining ph and the relationship with hardness!

http://forum.simplydiscus.com//index.php?board=5;action=display;threadid=1152

FYI, Ph is dependant on a number of varibles like hardness, CO2! ;) ;D

[Neophyte]

Ronca, I have read that and alot of other material on pH. I just meant if all things remain the same, except that the minerals become more concentrated due to adding tap water instead of R/O water for topping off a tank, would the pH become more base.

Believe me, with the hardness of the water here there is no danger of it becoming more acidic.

[Carol_Roberts]

Sounds plausible. I always do water changes and never just top off the tank.

[ronrca]

Yes, ph can rise when hardness increases but this may not by the case every time. ;)