Green Water Question

[SerranidTerror]

Oddly enough I am posting about green water.

Here's the deal. I got my g/f's dad a 75 gallon tank. He has 3 maxi jets on there, 2 emperor 400's, a sump he fashioned himself, and a sea urchin skimmer.

He's running a marineland 48" t-5 light fixture for 8 hours a day, has about 75-90 pounds of rock, shallow sand bed, uses instant ocean salt, and has a coralife RO unit.

He's claiming 0 nitirites, 0 ammonia, and 20 nitrates. pH is 8.2. (not sure what brand he's using.)

He has 1 yellow tang, 3 damsels, and 1 clownfish.

His water is just a green soup with viz on par or worse than the delaware bay on a bad day!

Oddly enough when he first installed the sump the water cleared up in 24 hours and his tank will go through cycles where it is green for 3 weeks, he has a die off, and then it will come back in 2-7 days.

What am I missing or assuming?

 

[emonemo420]

its an algea bloom of some sort....best i can say for being a newbie but his water paramaters cant be right..or his water source is bad...make sure to use good quality R/O water and keep up with water changes and maintence

 

[kaptken]

Ahhh! Interesting problemo!

With such a small fish load, and probably feeding, the algea might be experiencing phosphate limitation which could account for the cyclical die off of green water. even though the nitrates are high and abundant. The two hang on filters are pure nitrate factories. the small amount of rock and shallow sand bed do not keep up with denitrating. in fact the shallow sand probably adds to it(aerobic) . lights are not the problem.

What the tank needs is a denitrating strategy/structure. If you dont want to experiment with live deep sand beds(tricky) or plenum sandbeds( expensive grade of aragonite) the best thing to do is add a full flow refugium directly inline with the tank recirculation flow. skimmers dont remove much waste once it it processed into nitrates, they get it before hand.

So what you need is something to remove or CONSUME the nitrates.

You need a full fledged FUGE!! In "D" eep sand bed major!
Enhanced by the brilliance of light!

Worthy of Johan Sebastian Bach!!

 

[emonemo420]

ken i worry about u sometimes

 

[Gordonious]

Lol. Yeah I agree with Ken, a refugium would probably help in the long run. A quicker fix might be a UV sterilizer, but if the water is really green a UV sterilizer might kill a lot of it off and add more nitrates to the water... Maybe. I dunno. Need more opinions on the sterilizer.

 

[firecrackerbob]

I agree with the need for a Fuge... personally i believe a refugium is bar none the best water management tool you can have for a reef. I put them ahead of skimming, but I know many would disagree.
For his situation I would recommend getting the fuge together ASAP, check out the skimmer to make sure its pulling as much gunk out as possible, and to check his TDS. Assuming the RO water is of high quality(you might want to add a DI stage), start doing weekly 20% water changes. I would also start running polyfilter and phosban.
Here is a page I wrote about beating my algae problems. it was hair algae for me, but it should help regardless:
http://www.wikisift.com/wiki/index.php?structure_id=33

Hope this helps
Eric