need help, I'm at a loss

[JAANDGC]

Here are the specks,
The tank is a 240 gal. sps tank
1630 watts of light (M/H & VHO)
12,000 gph flow (tunze, seio,return)
cal 380-400
alk 8ish
phos,trates,trites all 0 on salifert test kits

Here is the problem
Alot of my sps's are rtning/stning. I say both because it is really not either one, What I mean by this is in one shot I might loose 3 or 4 inches of a coral, then it will be fine for a couple of days to a week then it will loose another couple of inches. The loss is not tied to any certain area of the tank, High light, low light, high flow, low flow. It doesn't matter.
I have tested everything I can, I use ro/di for make up water (tds is 0) The tank is almost fully automated with my ACIII, and everything stays stable.
I have done a half dozen water changes (30 gal each) over the last month and a half, and nothing has slowed down. (yes water parameters were the same on new water)
I have taken several frags and soaked them in fresh water for hours shaking the mess out of them looking for the normal pests (AEFW,red bugs) but have not been able to find any such pests at all. And yes I have had red bugs before so I know what I'm looking for.
The only thing I have noticed is some times around the area that has just died, there is a film of something, I would think it was some type of bacteria, but I don't know this to be true, and It only shows up every once and a while.
So what do you guys and gals think this might be, and please under stand I have been keeping reef tanks for going on 16 years and a thriving sps tank (untill about 2 months ago) for 3 years.
Oh and one more little tid bit, the corals are still growing very good and encrusting on the rocks that they touch within a week, and they all keep pretty good color. well up untill their flesh falls off!
Jerry

 

[NaH2Ofreak]

What kind of fish do you have in there? Any nippers?

Dennis

 

[easttn]

Check your bulbs too. Any cracks or extended life issues. Hope its not the run of the mill bug issue.

 

[Sk8r]

I'm new to sps, so this may be a stupid remark. If so, excuse me. But I wonder if it isn't a bacterial infection. Could something like Chemi-clean or maracyn help without damaging them further? I've not used maracyn, but my stuff all came through a Chemi-clean dose with no problems, and I know other people have used maracyn with no ill effects to speak of.

 

[kahunakatz]

Please let us know your salinity, temperature, and pH as well as what brand of test kits gave you those values. What kind of salt do you use. Your alk seems a little low to my taste, but I don't think that alone would cause the problem.

The softies in your tank MAY be a part of the problem especially if you don't do many water changes and if you dont run activated carbon.

Its a start.

Best Wishes,
Barry

 

[JAANDGC]

Ok lets see
no nippers, and as much as I loose in some nights the fish would look like a light bulb.
I have looked at the bulbs (xm10k's) and did not see any cracks, plus if this was the problem, it would mean all 3 bulbs were bad, and the odds of that are slim, and they are about 4 months old.
As for a bug issue I have checked and will continue to check for them but I have not found any yet.
salinity1.25 refractometer
temp 78deg. +/- .5deg ACIII & chiller controller
ph 8.1 - 8.3 ACIII and was just recalibrated 2 weeks ago
As for salt I/O
There are no softies in the tank any more, well I do have some zenia, but thats it. I know I need to change my sig.
I do monthly water change and run about 2 cups of carbon in a mag 350 canister. (always have )
As for the bacteria, I really have thought about that several time, but I just don't know if that is the case, I do have some chemi clean, so I might just try it any how.

 

[icu2]

Did it all start after you replaced the bulbs? If you did not acclimate them to the bulbs, you may hae bleached them.
Just my .02

 

[JAANDGC]

It started about a month and a half after the bulbs, none of the corals bleached out.

 

[kahunakatz]

Are the calicum and alk results from a Salifert test kit. Corals Calcify mostly at night and if that is when you are loosing them there could be a problem with calcification. Is there much nuisance algae, which would show PO4 not in the water column. Also dosing amino acids MAY help the corals calcify.

If you can remove the affected Acros and give them an iodine dip that may help too.

I would also lower the temp if you can and raising the alk a little should help also.

Best Wishes,
Barry