I have 4 planted tanks, all of which have developed problems in the past couple months. OK, a couple of them for many months. First the parameters:
All tanks are CO2 injected, canister filter of various brands, PC lighting over 3 Watts per gallon. I used to dose individual nutrients but have changed to PMDD. Mix Tap water/RO water.
2 tanks have never settled. I have had all sorts of algae problems, the worst being blue-green algae (cyanobacteria) that took months to clear. I finally resorted to erythromicin which worked like a charm. All 4 tanks seem to have developed BG algae, green thread algae, and now brown slime algae. The brown slime develops only near the top of the tanks.
I decided to switch to PMDD because it is simpler and my life has gotten more complicated. I also thought maybe I could control the algae better.
I've only been doing PMDD for a few weeks. After a couple weeks, ALL the algae died out the tanks. Good. Then I developed brown slime algae AND the plants started showing deficiencies. In all my tests, Nitrates are around 5ppm, NO phosphate, and as far as I can tell, NO iron. But my iron test might not be any good anymore. The red plants are REALLY red and even the crypts are looking redder than usual. The sags are really light green and the hygro kompakt is yellow around the edges. some leaves show holes but I think that happens after the leaves die, not a deficiency. Still have brown algae growing.
So I started adding some phosphate every couple days. I also added Epsom salts to my PMDD (didn't think I needed it the first time) to make sure there was enough Magnesium. I also doubled my dosing to 4 drops per 10 gallons since it seemed there was not enough of ANY nutrients.
So here's the pictures. All the plants are actually starting to do better, though the brown algae is still growing like crazy. Should I just continue, allowing more time for my new dosing regime to settle? Or am I missing something? Could it be old bulbs? It's been about 10 months so maybe time for new ones. I change 50% water every week, though or a while it was closer to 10 days for most. I've also been cleaning the filter every week instead of every 2 or 3 like I used to.
Open to any and all suggestions/ideas. I'd like to hope I'm on the right track and the tanks will settle down if I continue.