Corals Dying-Help Needed

[Ktaril]

I began fragging sps corals about eight months ago and have struggled since the beginning. The corals look great for 2-3 weeks, then bleach/discolor before eventually dying. Last week I changed the height of my lights from
15" above the water level to 28" above water level. Does anyone have any ideas on what I'm doing wrong and/or right, for that matter?

Glass Tank: 4'x3'x8"
Lighting: 400w 20k metal hallide light on a light rail
Water Flow: 2 Maxi Jet 1200 pumps, Pump in sump runs 1000 gallons per hour to tank
Filtration: Filter sock, 100 pounds live rock, 80 pounds of live sand, Marineland Marine Pro 300 protein skimmer
Calcium Reactor with a American Marine, Inc., pinpoint PH controller, ReBorn calcium reactor media (This is not currently being used because at one time the calcium was at 500, the magnesium was at 1500, and kh was at 12. Now, I believe the salt I use (SeaChem Salinity) has helped maintain the calcium, magnesium and kh to the levels listed below.)
Water Conditions: Calcium-440, Magnesium-1400, PH-8.3, KH-8.9, Ammonia, Nitrates, Nitrites, Phosphates are all at 0

I've had success with reef tanks in the past, and so this is very confusing and frustrating; does anyone have any ideas?

 

[Trademark]

Have you read any par readings at the level your light is at?

 

[Alexraptor]

Would also be good to know what kind of SPS were talking about here, Acro, Monti, Seriatopora?

 

[Ktaril]

The majority are acropora - valida, austera, subulata, gemmifera among others, and also a few millepora.

 

[dahenley]

400W light on that shallow of a tank especially at that low of a level will nuke some stuff....

i run 400"s on my 24" tall tank and have them 16" above the water and keep clams and SPS happy on my sandbed... so im sure you killing them

a par reading is what your going to need.... (its probably a slow death since its on a light rail and its taking longer to cook the corals)

 

[coralreefdoc]

You were likely getting 800+ PAR #s on those frags :hmm2:

With a footprint of 48x36 and a height of 8 youd be better served with 3-4 150w, or 2 250w lamps higher up for spread, vs a single 400 on a light mover

 

[CUZ]

agreed it definately sound like to much light!! How are the pieces dying, from the base up or from the tips down?

 

[smsreefer]

agree 100% on too much light.
150 - 250w on a rail is plenty.

 

[Ktaril]

Thanks for the advice - this is where I was headed, but it really helps to have the positive confirmation. It appears to me that the corals are dying from the base up, but some just seem to turn white/fade color - it takes awhile and then just dead. Should I leave my rails where they are - which is at 24", or should I adjust the height when going to a 250w? Is one 250w enough on my rail or do I need two?

 

[joesfiddy]

I would do 2 I have one 250w over a 36x24x8 and it's almost not enough for it. I'm 17 inches off the water.

 

[smsreefer]

Thanks for the advice - this is where I was headed, but it really helps to have the positive confirmation. It appears to me that the corals are dying from the base up, but some just seem to turn white/fade color - it takes awhile and then just dead. Should I leave my rails where they are - which is at 24", or should I adjust the height when going to a 250w? Is one 250w enough on my rail or do I need two?

One on a rail is all you will need.
The height really depends on your reflector and the spread of the light .
Knowing the PAR levels is the best way to determine the height you need.

 

[Trademark]

I second knowing what the PAR levels are. This tell you exactly what you need. These meters are invaluble when growing frags out. Especially when at times you need everything on your side to make it work and keep your sanity.

 

[Ktaril]

One more question on this topic. What are your thoughts on whether I should attempt to frag some of the larger corals now, or wait until I can get the new light installed and see how that impacts them? Just not sure whether it's better to wait or try to frag and save them.

 

[dahenley]

Can you not move them to a display and let them recover till you downgrade lights?
If you keep or frag them.... your going to continue to cook them with your current lights... so its up to you.

 

[Ktaril]

Downgraded to 250w lights yesterday - so will give them some time to recover and then go from there. Thanks again to all for your help. Now let's see if I can save what's left .. . . . .

 

[dahenley]

Because they are stressed, cut the light cycle back (just because ) and bring it back to a normal cycle over a few weeks.
Keep watching, and if a certain coral keeps having problems while others are holding steady, then go ahead and frag. Otherwise keep them whole till they are better. Then you have the choice of fragging the dead off, or keeping it.

 

[reefbooger]

Are your lights HQIs or mogel based?

 

[reefbooger]

The reason i ask, i have a family member who bought a used 400w HQI lighting fixture from our LFS. I helped him install it and we positioned it the same height has is old 250w fixture. It worked wonderfully for a few weeks till he started having having temp issues. We discovered that one of the fans quit working in the unit. We removed the glass from the fixture, replaced the fan, but we decided not to replace the glass thinking that would help it run cooler. BAD desicion!! We fried his tank in a matter of hours. We didnt know the glass acts as a UV filter in HQI fixtures. You live and learn I guess!!