Re: Aquatic Plants Digest V1 #20

stevensj at calshp_cals.wisc.edu writes:

>> add sodium bicarbonate to keep my carbonate hardness up and my pH
>> stable

> I don't think this is a good idea.  Sodium bicarbonate will also raise
> the pH, not stabilize it.  Again, DIY CO2 is your best bet IMHO.

Then what is the recommended way to raise carbonate hardness? I'm not
likely to inject CO2 with a carbonate hardness of roughly 30ppm
(that's around 1.7dKH). I realize that without CO2 injection, adding
sodium bicarbonate will raise the pH (since it will change the
equilibrium value), but since my plants appear to be sucking all or
nearly all the CO2 out of the water anyway, it can't go too much
higher, right?

Anyway, it seems to me I should increase the hardness before risking
large pH swings with injected CO2.

I still have no idea what caused my phosphates to rise. I did not call
the water company; the tap water tested negative for phosphates. My
tank's phosphate concentration is down to the edge of measurability
with my LaMotte test kit; I can only surmise I missed a spot when
cleaning the gravel, and let some uneaten food or other spoo
accumulate and rot. If it comes back I will investigate more