Too Much Light??

[tripnbili]

I have a 75g mixed reef...specs in signature I believe.

I'm running 2x250w MH (Ushio 14K) and 2x110w VHO (super actinics)

Nearly all of my corals are exhibiting poor polyp extension and some bleaching. I have some palys in the bottom of the tank, and they are retracting...my nuclear greens have nearly no stalk, look like funky zoos. And I bought a frag of about 20 "Lord of the Rings" palys about a month ago, and they have retracted considerably.

The light fixture is a Hamilton and it was about 8" from the surface. About a week ago I raised it another inch and today I raised it one more. These measurements were from the bottom of the fixture (the bulbs are actually in the top of the fixture).

I just measured and the actual bulbs are now about 14" from the water surface...I guess they were about 10-12".


I guess my question is could this have been a case of too much light? And if so, should my recent adjustment help matters?? Thanks


pH: 8.3
sg: 1.024
PO4: 0.03
NO3: 0
Mg: 1300
Ca: 480
dKh: 9
Temp: 78

Flow: 2xK3's and 1xK4

[mfinn]

Maybe if you suddenly added the 2 mh's at once and the corals didn't have time to ajust to the light.
But too much over all. No
I use a 250 watt mh 20K Radium on a PFO HQI ballast with 2 x 75 watt VHO on my 18" tall zoanthid tank.
In my 240 I have 3 x 250 watt mh with 4 x 160 watt VHO and it's all soft corals.

[Reefman29]

+1 on the too much light righ away. Maybe add like a bulb per week or something. One metal halide, then the actinic then metal halide

[tripnbili]

Thanks....I did my best to acclimate all corals, but obviously not good enough...

Now, when I buy new stuff I'll prob have to put it low in the tank etc...

Also thinking about switching to 20K Radiums...I hear good things about those

[Toddrtrex]

Are the corals new? Or are the lights new?

Like others stated, overall that wouldn't be too much light (( I have 2*250 + 4*54 T5 over my 75 )), but if the lights/corals are new, and you didn't light acclimate then it could be an issue.

I personally like to use layers (( 3 )) of window screening b/t the tank and the lights, with removing a layer every 5-7 days.

[Reefman29]

Another thought. Move ALL corals to the bottom. Then once a week move them up one "level" in the tank until they reach your desired spot.

[Fishamatank]

Are you carbon dosing? I had similar problems and it was due to the carbon dosing (or overdosing)

[shifty51008]

i run 2 400 watt mh's and 2 110 watt vho's over my 75 gal. and as long as you aculimate them slowly they will be fine.

[tripnbili]

Are you carbon dosing? I had similar problems and it was due to the carbon dosing (or overdosing)

No carbon....I'm pretty sure the lighting was too much at once on some of these corals....