Your water shouldn't be green. Is the tank sitting in direct sunlight? For a top you can use wire shelving. I made one for my 40 gallon tank. viewtopic.php?f=6&t=34076
1 Male Mississippi Map/Mississippi 1 Female RES/Slidy. 1 DBT White Concentric Female/ Lucky 1 DBT Male/ Spots (Housed in the same tank)
my apt doesnt have a lot of windows so there is no direct sunlight but my 20 gal never had this problem. Which after reassessing the problem I had a far smaller tank where the uv bulb bathed the entire area in uv light this new tank the uv only hits about half the tank would a second uv lamp clear it up or should I get a second filter I currently have a Fluval 406