Needing a little help

[yote]

With a customers tank.
Heres his problem:
He can't keep soft corals. Zoanthids, Xenia, Star Polyps, leathers, all melt away in his tank. LPS does great. He's not tried any SPS.
It's 150 tall , 40 gallon sump/ fuge. ETSS skimmer with mag drive 24 pump. Plenty of flow in the tank.
Stock list is a pair of True Percs, a Royal Gramma, and 3 Bartletts Anthias, 3 fire shrimp, 3 cleaner shrimp and an atlantic blue tang.
Parameters are perfect. No ammonia, nitrites, or nitrates. PH is 8.0 ( morning ) and 8.2 ( evening ). Calcium is 450 with an alkalinity of 10 DKH. 20% water change every week. Mag is 1300. He uses RO/DI with a TDS reading of 0.
Lights are 2X 250 watt Current halides with 8X 54 watt T-5s.

We've tested for everything we can think of including stray voltage. It's got all of us baffled and we've been working on it for about 2 weeks now. So I figured I'd see if Y'all can think of something were missing.

 

[FishyReef]

Parameters are perfect. No ammonia, nitrites, or nitrates.

I'm guessing that here in lies your problem - the water is simply too clean for softies to thrive. If he is set on a softie tank then I'd have him back off on a few water changes, get the nitrates up to around 10 and then try a zoanthid colony and see how it does.

 

[viperbjd]

+1 FishyReef

That was my initial thought as well...

 

[Civicdemon]

+2 Fishy but i would not really go that high on the nitrates maybe around 5 ppm, maybe if he does less of a water change. I here 10% a week is good and hes doing 20% a week seems like a bit much. Could save hime some cash also on salt.
Does he feed the corals ?? Phyto or anything ?? if not he might want to start doing that ones a week. I notice when i add Phyto with coral frenzy to my water the next couple days my corals look extreamly good and open. My Trates are about 3ppm and my psp and gsp Zoo and xenias are growing like crazy. Back when i was at zero i noticed my xenias where shrinking and my zooathinds where not really growing as fast and spreeding.

 

[Ted]

I agree the tank is to sterile...would be a good sps tank but for softies and zoahs need a little dirt.

 

[yote]

Thanks Fishy. Don't know why didn't think of that one.
Told him last night to cut back on wather changes and get another fish or 2 in there. When the nitrates come up were gonna give him some Zoas and Xenia to try again.
We'll see how it goes.