there's cheato in the refugium. About the size of a softball.. maybe a little more.
I added some rock to it aswell last week.

I'm using phosban at the moment but i used to have seachem's version.. forgot the name.

OK so if i understand correctly you have Green water. Is there any other algea in the tank?
Sorry but I have more questions
What type of lighting?
What K are the bulbs?
How old are the bulbs?

If you have a phosphate test kit what is it reading
How old are you current test kits?

Algea eats phosphates and nitrates. If your live rock was garbage it would not convert ammonia to Nitrite and nitrite to Nitrate. The end of the nitrogen cycle is Nitrate. You rock is not expected to convert Nirtate to anything. Ammonia and Nitrites are toxic to fish. So I would say your rock is doing it's job.
Odds are your Nitrates are not 0 and I'm going to speculate your Phosphates are through the roof.

J

the bulbs are old.. I bought new bulbs but ordered 96watt instead of 65 by mistake.
anyway they are dual 65watt power compact orbit lights. 10,000k and 460nm acitinic.
there's no other algae in the tank but the green water andt he cheato in the refugium.

I don't have a phospate test kit, and the other tests are about a year old.

i guess i'll ahve to order one.

asherah

How long has this been happening? Is the water cloudy grey? white? green? Keep using the PHosBan, the SeaChem version isn't as good. Your phosphate media should be dark reddish brown...if you have a white version it isn't nearly as good.

ok it is white.. i didn't even know there was a brown kind.. i'll have to try that too then.
the water in the tank is green... =(

it's been doing this for months!! I thought I had it cleared up but I was wrong!

asherah

I would get rid of that filter and go canister... but that's my opinion, I like canister filters and I have found that overkill is good for a marine system. I do battle with green hair algae but it is getting less and less as time goes on.

as for light bulbs you should change them every 6 months if they are florescents wether they are burnt out or not.... as they are used they diminish in intensity gradually and you won't notice it until you put in a new bulb.

I love my cannister filters, and wouldn't even think about using a little aqua clear on a marine system. that's just my opinion though. like I said earlier on my 10G nano I run a fluval 404 (which is for a 100G tank, so they say)

what are your test readings for the water anyway?
ammonia?
nitrites?
nitrates?
phosphates?

Skip on the canister filter, unless you are prepared to do a lot of work to avoid them becoming a nitrate factory.

1.) Up your water changes in frequency, and possibly in size (say 10% total volume per change).
2.) Get your new bulbs
3.) Get new testkits and write on the top when you received them
4.) Set up a tracking method so you can track your parameters over a long period of time. A notebook works, so does an excel sheet.
5.) Run new carbon & GFO (phosban, phoslock, etc) and change them both frequently. HOWEVER when using GFO do not go right to the label's full dose immediately, work up to it.
6.) Patience, it will pass! :D

If I'm not mistaken, Nitrate is converted to Nitrogen (Denitrification). My understanding is that LR plays a role in this. There are certain bacteria in LR that support denitrification. The nitrogen is gassed off with good circulation and surface agitation. Not sure if this is relevant to your issues. Just 2 cents for the record.

Cheers,

Yes the theory is that with in the LR there will be anaerobic bacteria that converts Nitrate to Nitrogen. This is not always possible, with high bioloads and rock too dense or too porous.
that is why 'we' have added DSB, Refugiums, and Coil denitrators.
But having Rock that can not convert Nitrate to Nitrogen does not render it useless

J