Re: PMDD's and Hair algae

On Thursday, 4 July 1996, Paul Rothel wrote:

> Then I started making my PMDD mixture and adding that to the tank.  I
> use Microplex as my Iron supplement along with K2SO4 and KNO3. I keep my
> iron levels at .3 to .4 mg/l.  This may seem high but it seemed to have no
> bad effects on the fish so I thought it probably would be better for the
> plants. 

These iron levels are much higher than necessary.  It may take a long
time for your fish to develop problems, so the fact that the fish are
currently healthy isn't an indication that this is a safe practice.
Remember that you aren't adding just iron; there are quite a number of
trace elements in the mix that are potentially toxic (Cu, Zn, Co) if
their concentrations get too high.  The mix also contains EDTA, which
in excess can lead to skeletal abnormalities.

> However after a couple of weeks of this, Hair algea started to show up.  My
> nitrate levels were reading 0.  I even checked with another kit because I
> thought my lamonte kit might be goofy.  But sure enough my nitrate levels
> were still 0.

This is an indication that you need to add more KNO3, not less.  You
appear to have become nitrogen limited, leaving free phosphate to feed
the algae.  Try to maintain detectable levels of nitrate.
Kevin Conlin   kcconlin at cae_ca   "We're Canadians.  We HAVE to be polite"
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