Stuggling with Diatoms / Brown Algae in mature tank
I've been struggling with Brown Algae on plants, glass and rocks in a mature tank. On the plants it's always the lower leafs that are affected. Rocks are just covered in it and instead of seeing the nice grey/purple colouration of the Manten stone it's just a brownish color (If I scrub the stones the brown algae comes off easily).
I have no other signs of any other type of algae except maybe a tiny amount of green spot algae on the upper parts of some wood that's just by the water surface. I expect that's because it's so close to the light.
The affected plants are mainly stem plants which are situated where the highest amount of flow is, they are all swaying in the current and got plenty of space around them. For some odd reason the larger plants in lower flow areas (Echinodorus) are not affected it seems.
I'm dosing daily with 8ml TPN+, 5x drops of ECA and 5ml Excel every other day.
I have moved about some plants a few times over the last month, which each time has disturbed the substrate.
Tank and Equipment:
- 170L / 50g tank
- 3 x AquaRay GroBeam 1000 ND LEDs (PAR reading at the bottom of the tank is around 80-90)
- Inline CO2 reactor
- Fluval G6 (2460 lph / 1000lgh)
CO2: LimeGreen / Yellow
PO4 Tank Water: 0.3-0.4ppm
PO4 Tap Water: 1.8+ppm
I only today measured PO4 for the first time and noticed the huge difference between my tap water and tank water. Is there any chance that High PO4 in the water I put into the tank can cause this problem?
Or could it be that I have too low light?