Greenwater in tank w/ "proper" ferts?
So I'm a bit stumped. I have a 58G tank that's been running for about 6 weeks. AS2 substrate, low/med light (PAR=35) 8 hours/day, nitrates 22 (from the tap, no extra added), Ammonia of 0, and low PO4 (just because I forgot to add some from my last H20 change.
The tank has gone from white cloudy to a nice tint of green, and I have no ideas why.
I should add that about a week ago I had a nice white protein scum on the top.
To make me more confused, about 48 hours ago I put my 9W Turbotwist UV on the tank, and see no change, but rather it appears to be getting worse. I'm wondering if the bulb is weak, or if the 9W is just too small for the 58G. Coralife specs it for 125G, but the Green Killing Machine specs 9W at 50G.
Any ideas what might be causing the green tint on the water? It could well be it just needs to run it's course, but I hate the way it looks.