half of the stems of mermaid weed have rotten away:
In general: the tank is dirty. lot's of little particles, algae, water not very clear.
What worries is that I don't have to add a lot of PO4 and NO3. I guess that the rotting material provides that....
now the specs:
-1x a week 50% waterchange with 100% RO with sera mineral salt to 300 uS.
-daily: 20 ml TMG. I vacuum as much as possible the free floating dirt away.
-NO3: 20 mg/l measured with two reference solutions of 15 and 25 mg/l
-PO4: above 1.5 mg/l. I virtually do not have to add any PO4. measured by hanna spectrophotometer.
-CO2: 38 mg/l measured by oxyguard CO2 analyzer. 2x rhinox and an external aquamedic reactor.
-filter: 1x eheim professional, 1x eheim professional 2.
-powerheads: 2x 600 l/h --> very good flow in the tank!
-light: near surface in the middle of the tank: 230 umol. near surface sides of the tank: 180 umol. near bottom middle of the tank: 70 umol. 10 hours light.
Maybe a bit too much: I have today lowered the light to 180 umol near the surface in the middle of the tank.
In general, I cannot see why I have such huge problems. the light doesn't seem to be that high. but maybe a little bit less is wise.....
greets,
yme