frog girl said:
Will a bit extra
K+ hurt anything?? the difference in
GH &
KH is only like 1 or 2 degrees.
If you are using ONLY
RO water, then I would expect 0 for both
KH &
GH. That is not desirable, so most people have either added buffering salts or some regular tap water. Depending on what else is in the tanks water apart from
RO, that can very well explain what you see in terms of
KH &
GH.
Your fishies don't care a whit if your
KH &
GH is equal! In any stable system, all positive charges must equal negative charges. <If not you would have an ionized "Plasma" - found only in TV sets, flourescent tubes, surface of stars & the like!
> It just so happens that our
KH &
GH tests measures only some of the ions, giving you an unequal result. The rest of the ions, tho unmeasured, are still there. Your fishies senses all the ions (as total osmolarity), and within reason, don't care what the ions actually are.
I like to keep things simple. As far as fish tank goes, just make sure you have adaquate
KH (like 4 & up) to maintain pH stability. Other than that, you only have to worry about very high
GH &
KH, as this would induce osmotic stress.
BTW, if you have salt, the osmolarity will be high, even tho neither
Na or
Cl is measured in our
GH/
KH tests .... so those test really don't tell the whole story. And of cause, some fish like low osmolarity & other like high. So the simplest is to match your fish to your
GH & don't worry too much about it.