Testing, testing, phosphate limiting

["tomwood2" <tomwood2 at flash_net>]

My 90 gallon hit 'the wall' a couple of weeks ago. Bluegreen algae bloomed,
the plants stalled. I upped the CO2, potassium and trace mix. Nope, no help.
Hmmmm. I'm changing 20% of the water once a week with tapwater that 'The
Company' says has 1.0 ppm phosphate, so that can't be it. But, just to be
sure, I mail-ordered a new phosphate test kit because my old one went dry a
while back. I test for nitrate and it's in the red zone - more than 20 ppm.
I did several water changes - no help. What the heck? The phosphate test kit
comes. Two hours after making two 20% water changes, the kit shows zero
phosphate. I add some monosodium phosphate and the water tests off the upper
end of the chart. Dang, too much. Within hours the plants are exploding with
new growth. Wow, powerful stuff.

On a side note, I stopped feeding Tetra dry food because it has a lot of
phosphate, and because it has a lot of dried algae as components. I was
testing to see if eliminating the dried algae would have an impact on green
spot/dust algae. I 'think' it has, but I'm not sure. I've been feeding
sinking pellets designed for goldfish for a month, and now I have a
phosphate shortage. Curiouser and curiouser.... The tank looks great again.

All done with an $11 Seachem phosphate test kit and a $7 Aquarium
Pharmaceuticals nitrate test kit.

TW