Green Water - ARGH!
 

Ok... I'm running out of ideas - can't seem to get rid of the plague.

For some odd reason, I had a green water outbreak ... 2 weeks ago (?). Figured same as with FW, water changes, adding some carbon/rowaphos/kent nitrate sponge resins would make it go away.

Well it hasn't - I've done 4 waterchanges each at 100% (Ok 97%, there would have been a bit of water left). Water clears for 12-18 hours, then turns bright green again. Adjusted the skimmer to be taking out 2-3L of skimmate per day (vile green stuff). Hasn't helped. 36 hours of darkness didn't help.

What's changed in the tank? Replaced old Iwasaki 10ks with some noname 14k's - 2-3 weeks before this started. added a sailfin tang and hawaiian cleaner - sailfin did pass on (but body was recovered). Hawaiian cleaner may be gone, haven't seen him of late - but the tanks rather hard to see in.

Is there any filter media that will filter this stuff out? Water changes are starting to get a bit expensive.

Luckily corals haven't been complaining too much some SPS had to move upwards, but are still showing good PE, LPS are just loving this...

Uv
 

UV sterilizer....that will do the trick!

Some clams would just love it too, I bet.

What carbon are you using? I seem to recall in the past when there have been greenwater outbreaks there usually is some sort of source, the trick is zeroing in on it.

I would have guessed the problem is PO4, but if you're running Rowaphos and it's not licked then I don't know, I would have guessed Rowaphos would make a difference. If I understood PO4 better I'd suggest testing your PO4, but the problem is that test kits only measure inorganic PO4, and the source of your greenwater is organic PO4 (or vice versa or something like that). Thus I have a feeling a PO4 test reading probably wouldn't tell you much.

Neither the rowaphos or the nitrate sponge seem to be doing anything honestly (no color change other than going green). But then the GW is likely sucking up any nutrient which is causing this...

Carbon is HBH brand - dennis swore up and down it was "good stuff". Not one of my normal choices...

Anyone have a UV sterilizer for loan? :D

Are you using tap water or RO water ?

tap but w/c's have been RO.

Is the Ro water you are using from the grocery store? If you have a tds meter check the RO water before mixing it with salt . I don't trust the grocery store RO water units :twised: I had some problems in the past with their "RO" water. I purchased a home RO system and haven't had a problem since. Hope your water clears up for you :biggrin:

Not grocery store RO - those are a bit expensive for 80g's at a time... But no I didn't check tds - surely less than tap :D

What lights are on? I started my system with tapwater, and ran real bright T5 aquablues almost from the getgo, and never had green algae. Didn't run phosban/rowaphos or nothing, then too, and my first week of water changes was with tapwater. I had diatoms for about a week, then hair algae for about 3 weeks, though...

I think I remember reading that waterborn algae is caused by too little light?

maybe those nitrate sponge resins leech chemicals back if they're full? if it's a new tank, liverock cycling could fill them up quickly, causing a belated algae bloom once they leech back?

Saw in another thread you said it's getting better -- so thought I'd ask for an update here :) What do you think turned the tide?