Over this weekend I was at a party way longer than expected so my light was on for about 14 hours I came home to a bad outbreak of diatoms, plus the water was cloudy and the flow was reduced on my HOB filter. Fortunately, the sponge filter was going strong.
The tank this happened on is a 20g tall with T5HO, pressurized CO2, I dose iron to get my red plants to turn red otherwise no other ferts. The photo period is normally only about 5-6 hours. I could probably do a longer photo period but then I'd need to dose ferts and I want to avoid that since I have CRS and Corydoras Habrosas in this tank.
So far I just rinsed out the pre-filter sponge and flow improved. I then added activated carbon in case it is a chemical issue It has been two days and the tank is even cloudier, almost like a new tank with unrinsed substrate. Also when I woke up on Saturday I noticed about 50 tiny tiny baby shrimp and I'm afraid I'll suck them up in a water change so I've been putting that off.
I'm guessing that extended photo period caused my plants to bottom out some nutrients which then caused the algae bloom, which then caused the reduced flow, which then caused the cloudy water. I could be totally off base, but that seems what happened.
I'd appreciate any suggestions. I was hoping it would clear up on its own. What I plan on is a 50% water change and a 1x dose of micro/macro ferts and to lower the photo period to 4 hours. Before that booboo this tank has been running great for about 4 months with a snail outbreak being my only problem.