Something's missing

[nplummer at duke_edu]

In the last couple of months, my tank has gone through a series of algae
blooms and crashes.  The plants are growing very slowly, so I suspect they
are lacking something that the algae doesn't care about.

Tank is 20 gallon, 55 watt power compact, fluorite substrate, DIY CO2.
I change about 50% of the water weekly and dose with Seachem Flourish
according to manufacturer's directions.  Our well water has a very low
mineral content and is slightly acidic.  I can use it to water sensitive
bog orchids and carnivorous plants with no problems.

Initially, I had an outbreak of filamentous green alage.  At Tom Barr's
suggestion, I started dosing with KNO3.  After about two weeks, the
filamentous algae turned brown and died.  Then I went on vacation for a
week and came home to pea soup.

Massive water changes got the green water under control, but the plants
are still not thriving.  Proserpinaca palustris turned to mush.  Ludwigia
and Rotala Macrandra grew well for a while but then started to rot from
the base.  Hygrophila difformis is very pale and is producing leaves more
typical of emersed culture.  Java moss is thriving; It is practically the
fastest growing plant in the plant in the tank.  Didiplis diandra is
growing slowly but is still alive.  Lysimachia nummularia also seems to be
doing fairly well.

The fish are doing fine, and one of the amano shrimp is carrying eggs.

I have purchased some seachem phosphate to see if I have a phosphate
deficiency.  Is it possible that the Flourish isn't providing enough iron
or that some other trace element is limiting growth?

Nick

--
Nicholas Plummer
nplummer at duke_edu