Frank wrote:
Mister Gardener and Altum,

Must be my water - comes out of the tap with nitrAtes between 10 and
20ppm depending on the time of year. Any direct sunlite at all = green
water. Funny though, lights are on a timer and at peak light, I'm
putting 4 watts per gal. in the tank (4 hours). Late afternoon sunlite
would hit the tank if the drapes were open - every once in a great
while one of us will forget and leave them open - by the next morning
we have the start of an algae bloom. Hmmm - mabe it's just that little
bit of extra light that does it (?)
.................. Frank

How odd. You wouldn't think that one afternoon of sunlight would make
such a difference. If I were talking to anyone less experienced, I'd
suspect a touch of ammonia in the tank. Nothing like ammonia to get a
green water bloom. I'm sure your tanks are ammonia-free, though.

I noticed that Mr. G and I both have water sprite in our algae free
sunlit tanks. Makes you wonder about allelopathy. Water lettuce has
been demonstrated to inhibit the growth of chlorella (green water) in a
couple of different scientific studies.

I don't have nitrate in my tap water, but I spike nitrates up to about
10ppm after each water change. The water sprite loses its healthy green
color otherwise.

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