Coral issues

My reef really perked up when I over hauled my water flow. Even their colors seem to be getting brighter. I was a non believer about super water motion tanks, but I am changing my mind....

I did a 40 gallon water change about a 1 - 2 weeks ago.... I did not see any improvment from the change... my tank is 180 gallons, with a 40 gallon refugium/sump.  I have one over flow on a closed loop, the other goes through the sump... Both overflows are pushing 700 -800 gallons an hour I beleive (around that last time I figured it out)  I have also added a modded maxijet 1200.  I am not sure what that pushes.. but I figure at least 500 gph.

Dion is thinking the same thing as me.

Have you tested for iodine?

If it was a drastic problem with water chemistry then I would think that pretty much all corals would be affected. I agree with Suzy, I think you have a problem with flow. In a long tank such as yours GPH does not make much sense since the flow out of the nozzles will quickly drop off in velocity. Turnover is not the only critical aspect of flow, you also have to phsyically move water past the coral to help it in respiration, feeding and excretion. It seems like the return nozzles are at the top and the problem corals are at the lower halfs of the tank? You could look into making the stream mods for maxijets which move a large volume of water without making the water into focussed jets.

EDIT: Doh, just reread that you indeed have a modded maxijet (I assume its the stream mod), but I dont see it in the pics, is it behind the rock work? What is the length of the tank? I think it would be better if you have two of these stream mods, at opposite ends of the tank and about halfway down from the top.

FWIW in my little 20g tank I have a Tunze 6025, 2 MJ900 and 1 MJ400 moving water. The MJs are on a wavemaker and the Tunze is always on. If all of them are on at one time I'd have 1200+gph. But in reality the turnover alternates between 890 and 1000gph (due to the wavemaker timer), but after reading a few articles that Adam Blundell posted on water flow, I dont think GPH is an accurate way of measuring flow (since flow is not the same as turnover).

Edited by sshm - February 12 2007 at 3:36am

I didn't read this whole thread so this may have already been said...

could something be irritating the zoos? something picking at them? If you've noticed polyps disappearing it could be zooanthid eating nudibranches or predatory worms.

Crabs will eat zoa's!  If there is not enough food for them that certainly can eat them.  I have witnessed it going on in my tank.  At first I thought the perpetrator was just picking at the algae around the zoanthid but then I witnessed it tearing off pieces and eating them.  Out it came and the mystery of the disappearing zoa's solved.  JME......

When I viewed this thread earlier I couldn't see the pics.  Now I can.  To me it is obvious now.... new tank.  It just looks very barren and in need of nice live rock to get it going.  I'll bet that whatever you do have in the tank (fish, crabs, critters) are just picking at the zoanthids and the zoanthids aren't able to grow because they can't acquire what the want from the water.  I think it just needs time.