Green water sucks!

[AndyL]

Ok, need help... Obviously I'm missing something major since this has reared its ugly head again.

Frag tank has turned green again (6 weeks after the initial bout). Started going a bit cloudy last week, did 3 35g w/c's (tues/wed/fri), replaced my rowaphos/nitrasorb and carbon. Looked good again, this morning it was green.

Tanks a 55g, 20g sump, 2x175w halide (14k's), Coralife 220 skimmer (pulls about 175ml of goo / day), 20ish lbs live rock (not including the big hunks a few of the colonies are on). Fairly substantial amount of chaeto and grac.

With the rowaphos/nitrasorb and all the macros, never see measurable amounts of PO4/NO3, Only test thats showing a bit off - is pH is running a bit low - in the 7.9 range.

Anyone have ideas? Going to try changing bulbs, they're only a few months old - but they did get changed not long before this problem started popping up...

Andy

[Psyire]

I've seen this problem corrected by running a higher pH.

[midgetwaiter]

I don't have many ideas about where it's coming from but I bet you could fix it by adding some live rotifers. Your corals would probably like that too.

[Johnny Reefer]

Not that it's necessarily gonna help your greenwater issue, but....I'm pretty sure NitraSorb is for FW only. IMO, you should switch to Nitrate Sponge for SW.

Edit: But then, if your nitrates are undetectable, maybe you don't need any nitrate removing media.

[Nate]

Start running a UV sterilizer, run a low amount of flow through it and it should be gone in three days.

Any chance your caulerpa is going sexual on ya? How does it look? Does it happen after cleanings?