Minimizing phosphates not effective?

• pH:
• Temp:
• KH:
• GH:
• NH4:
• NO2:
• NO3: 5-10 (after dose)
• PO4: 0.75 (after dose)
• Iron:
• Dosing: 5 mL iron chelate (0.5 ppm), 10 mL KNO3 (2.5 ppm), 10 mL KH2PO4 (0.4 ppm)

Notes:
It's only been a couple days with minimum levels of phosphate, but the water is still cloudy. Interestingly, almost as soon as the lights go out, the cloudiness clears right up, and as the lights go on, the cloudiness increases over the day. I decided that minimizing phosphates wasn't having much effect, except to possibly slow down plant growth, so I dosed some phosphates and nitrates today.

I've noticed that when I dose phosphates, plants will grow faster and bigger. The stargrass leaves are double the size of what they originally were when I first received them from an online retailer. Without the phosphate dosing (ie phosphate levels near zero otherwise), plants seem to grow more slowly, with smaller or even stunted leaves. Usually, the Rotala indica grows 6-10 inches over two weeks, but currently, the growth is noticeably slower, and some of the leaves are smaller. The algae levels haven't been changed much with the lowered phosphate levels, though.

Over the past several days, there's been this new brown gunk that looks a bit slimy and goopy. It does not seem to really attach to anything: water currents will blow it off of plants, but it is there on a majority of the plants. It does not have the same appearance as brown diatom algae, which has more texture and is more clingy and clumpy. I assume it's some algae, because even when I clean it out, it will reappear the next day, though I'm not positive, since I haven't seen this type before. Perhaps it's dead algae remains? I dunno.