>
>1) As for me... I don't currently test for phosphates. So do you
>think phosphate testing my water before I make my weekly water changes
>might add value?
>
>2) If phosphates are high, what remedy do I then take?
The high phosphate levels I've seen referred to in the SF area were from
Marin County, which has an entirely different water source. And the level in
Marin is 1 ppm. Not high at all, but non-zero, which turned out to be good
for the planted tanks.
To measure this level, you need something like the Lamotte *low*-level
phosphate test. And it's expensive, and it's near-junk, with a color
comparator that is not at all the same color as the test. Take readings in
natural light only, they say, but that doesn't work either.
Anyway, what PO4 level could present a hazard to fish? Has anyone heard
of it as a possible hazard? I'd bet on many, many parts per million as the
level that could cause problems..
Bottom line: not worth it to test phosphate unless you're trying to regulate
a planted tank, and dubious then. Disclosure: I measure phosphate in my
planted tank; but I like tinkering with chemical things, and I've ceased using
the color comparator, using a control solution of known PO4 concentration
in parallel with each test: that's how bad it is.
-- Dan Drake dd at dandrake.com http://www.dandrake.com/ porlockjr.blogspot.com