Reef Tank Problem

[rwrvetn]

I am a newbee to reef tanks although I have had community salt tanks up to 1000 gallons. Had a very knowledgeable individual set up the tank and equipment. Live rock has been cycled for months and all fish are healthy and doing well. My tank is aproximately 200 gal and sump 75 gallons. I have a 3/4" overhead flow line and three 1/2 lines which alternate flow (3 at top and one under major coral stand). My protein skimmer and U/V light are working properly. The tank has three 400 Halides, two 96 w Actinic/Flor, and moon lights cycling on controller. I have excellent flow and little to no bottom material other than live rock.
My tank parameters: Temp: 74.1-74.8 degrees. Ph 8.32-8.46 Specfic gravity 1.024 Calcium 500 Posphates 0 Nitrites 0 Nitrate 1.0 Iodine 0.08 Magnesium 1750 Total Alk 4.0 (Carbonate 3.0-Borate 1.0) Strontium 90. These parameters have stayed very constant. My question: Brains, anemones, Xenia, snails, crabs, brittle and red stars all do well over the past few months. Almost all new corals or inverts I have introduced will not survive. Some corals become necrotic and slough in 3-7 days. I use a drip system of aclimation over 4-12 hours with a triple water replacement volume at the ambient tank temperature. They are floated for 30 minutes before release into the tank in subdued light or darkness. I need some suggestions as this is getting very frustrating. It appears to me that old tank residents are able to survive, but any additions do not. Thanks for your imput.

[DaddyJax]

I have to say that the temp is a little cold!! Also the alk should be higher for 500 cal. This is my opinion but it may be what is giving your corals such a hard time.

[rwrvetn]

thanks for your help, I can certainly get the temp up! Appreciate your comments

[DaddyJax]

I keep mine at 78-79 and my alk up to 9. I have read many experts tank profiles and this seems to be consistant.

[Agu]

I'd agree that temp is a bit on the cool side however I don't think that's your main problem Bring up the temp to close to 80 to mimic the temp that most of the corals available in this hobby are accustomed to.

What corals specifically have you had die off and where did you get them ? (mail order, LFS (no need to name the store), or other hobbyists ).

That's a lot of light over your tank, are you acclimating for light intensity too ? Even high light corals need to be acclimated if they've been kept in holding tanks with lower light.


Good Luck and

[welcome]

[DaddyJax]

Thats true I didn't even think of the acclimation!

[bgdiving]

Your alk if it's measured in Meq/l is ok but if it's measured as dkh it's too low. Temp might be a little low but not likley the main problem.

My guess would be the lighting is too bright compared to where the corals had previously been held. How high above the water are your 400 halides?

[rwrvetn]

My halides are 5 " above water. Depth of tank about 18" to substrate. Always start new additions at bottom. Thanks

[robthorn]

just curious how you got your magnesium so high. 1750 is an extremely high number and no matter how much I dump into my tank I have never been able to get over say 1450. alkalinity magneium and calcium all work together. I am not sure of the effects of such high magnesium. I would worry that if your alkalinity is up to 4 meq/l as alkalinity is measured and your magnesium and calcium are also very high that the later 2 may start to precipitate from the water and cover pipes and moving parts within the water and cause mechanical problem as well as asthetic problems. if you are running your calcium and magnesium so high it may be in your best interest to not run as some claim to be balanced so you can prevent this situation. keep your alkalinity under what you are running and not go much over. I would say where you are would be the max level to run.
alot of people run there tanks cold without a problem I have seen stores run at 75 or under to keep down parasites. it worked for some of them but it is something you can try to see if it helps.