Need Help

[heinze]

I had a reef tank set up and running for about 2 years and every thing was growing and looking great.
I then decided to invest in a new one, 500 liter tank 50 liter sump with turbofloat 1000 skimmer, various trickle plates, auto top up, and two 250 watt halides with two actinic T5's.
once every thing was set up and running i started to get a brown algae covering the substrate, which i was expecting. But the problem lies with i have still got it 6 mounth down the line, and not only is it on the substrate is covering all the live rock, corals, polyops and every thing in there.
I syphon it off regulary with my 10% weekly water changes but with in hours it is back. i've tried every thing i can think off and have found on the web but it is slowly killing everything.
Please help as i love the reef and i'm going to have to give up soon and get a dog... please....

[Samper]

It would help to know your water parameters before starting with the advice. If everything is ok parameter wise then you may simply need some janitors. Without a good cleanup crew to mow down algae...both in the artificial environment and in nature algae will take over.

[heinze]

i've taested for nitrate's (NO3), phosphates, calcium carbanate harness and that's all the test kits i've got...... Results

nitrates (NO3)... 2.5 p.p.m and below. test kit is only that acurate
Phosphates (PO4)... 0.1 p.p.m
Calcium...... around 400 - 450.
Carbanate Hardness... KH 7.7dkh Alkalinity 2.74meq/l

I'm guessing the phoshpates and nitrates are fairly low due to the algea using it up before i'm getting a chance to test for it. but then again i might be wrong. I have not got much of a clean up crew as i have lost a few things in the last few months. my tank now consists of
7 or 8 hermit crabs
2 or three turbo snails
1 yellow tang
7 cromis
1 coral bauity
1 royal grama
2 clowns
1 toby
1 pink tailed trigger.
Any help you could give me would be much approved....