[john1105]

I have a colony of micro red zoanthids that as of late has not been doing very well and I can't put my finger on the reason why. All of my parameters seem to be checking out:

Temp: 77
SG: 1.0245
pH: 8.15
Alk: 9 dKH
Nitrate: 0
Nitrite: 0
Phos: 0
Calc: 480

All of my other corals seem to be doing great and are nice and full. My other corals are a small hammer, frogspawn, green striped mushrooms, orange ricordias, huge xenia colony, and an open brain. My fish are two false percs, a royal gramma, snowflake blenny, and one spot foxface. In addition to fish I have a BTA in the tank that has been doing well. I also have a few shrimp and the requisite CUC.

The zoanthids are near the top of the tank where they will get the best light under two 96 watt pc fictures. They are getting a decent amount of flow from a hydor powerhead. I really am at a loss as to why these are not doing well. They seem to go through phases every couple of weeks when some will close up and die off. Then they will go back to opening up and looking great again. It is almost as if the colony is culling itself every so often. Does anyone have any ideas as to what could be causing this? I don't want to lose this colony all together. Please help!

[RyanG]

John, try getting your PH up to 8.20, it's low

[john1105]

Hi Ryan,

I know the pH is slightly low, but I didn't think it low enough to cause problems. I will see about raising it up a bit. Is there anything else you might be able to think of that could cause this problem. As I mentioned in my earlier post, it seems to happen every couple weeks that the colony has a bit of die off. Thanks again!

- John

[RyanG]

Does the colony coincide with water changes or anything else you do at that time?

[john1105]

It does not seem to coincide with water changes. I alway use ro water and am currently using Instant Ocean salt mix. I do 10% water changes every two weeks and it has served me well so far. I have not noticed the colony doing worse right after a change. The time between the crashes differs as well. Sometimes it is a couple of months in between a crash, and sometimes it is only a few weeks. I am thinking that the crash right now may be due to my bulbs. They are about 10 months old right now. I have ordered new bulbs and they should be here on tuesday. I am not sure if this will solve things or not because the problem was still happening when the bulbs were still good.

[RyanG]

And by "crash" you mean that a few of your zoos wither and die? Dissolve and die?

[john1105]

I guess "crash" may be a strong term. A number of them will close up and remain closed until they die. So far I have not lost enough of them that the entire colony is in danger. Usually it is four or five poylps that will close up and then never open again. When they close up they then slowly disolve away over the course of three or four days. At the same time the rest of them take a much longer time then usual to open up when the lights come on.

[RyanG]

Try doing the following:

Drop your calcium level, you have a low need for calcium in your tank since most of your corals aren't demanding it. A range of about 350-400 is best. 480 is way to high.

Raise your PH level up to 8.20-8.30, whatever you set it at make sure it's consistent. It will fall in the night, but it should rise back up when your lights come back on.

[john1105]

I will give it a shot. Thanks for the advice.

[NYreefNoob]

8.15 isnt low on ph, mine flux's 8.-8.2 and just because you mainly have lps doesnt mean to keep your cal under 400 450 is really ideal, frogspawn and such still need cal to grow as well as do most lps , as for the zoa's re they a newer addition ? did you dip them before putting into tank ? check it for nudi's also, also could be a parasite, ive also found that usually twice a year i have some zoa's just start to melt, never figured it out, i have around 30 different morph's also watch the blenny, i use to have a starrey eyed that use to eat them, what test kit are you using ? phos is never zero, btw other then alot of zoa's my tank is mainly sps