How much does salinity effect stony corals?

[DrGrotto]

Hello,
I just purchased two corals from my lfs. One bubble coral and one frogspawn coral. Both looked great in the dealers tanks! I get them home, acclimate them, put them into the tank, and now about a week later the polyps will not fully expand. They seem to creep out in the morning and expand and contract all day until evening when they completely contract. I am not sure what is causing this. I also have an older Torch coral that is doing fine along with other corals like xenia and favites and such. They are all doing great.

My parameters are:
ph 8.2
no 0
no2 0
Sg 1.021
Nitrates are high, but they have been for some time...(I'm having trouble keeping them down.)
alk 4
phosphates .02
temp is around 77-80 during the day
I have a 58 gallon tank with a 20 gallon sump. Good lighting plenty of live rock.

I don't know if it's my sg or the nitrates...but I am getting frustrated. Any help is appreciated.

Thanks...
DrGrotto

 

[Anonymous]

I'd say your nightrates and phophates are a problem. Are you using RO/DI water for WC and make-up water.

You need to do a series of WC's until your readings are lowered significantly.

Also, where are they located in your tank? Improper lighting or current flow can effect the way a coral responds.

 

[linuxpng]

the same question because my frogspawn wasn't expanding. My SG was at 1.022. I was told it should read about 1.025. Well looking through some books I had, somehow it never dawned on me when reading them that it recommends these higher salinities for reefs. I slowly raised my SG to 1.025 and the frogspawn has completely recovered and expanded out. This happened over 2-3 days. Just my experience from great advice I'v received here.

 

[CraigLampe]

I also have SG 1.025 and frogspawns, torch, hammer do EXCELLENT!! Actually, almost too good when they sting my SPS!! I would try SLOOOOWLY adjusting this parameter!!

 

[esmithiii]

Natural sea water in the vicinity of most reefshas a specific gravity of 1.0265. I would suggest raising yours to get in the proper range (slowly!). The most likely culprit, however is the high nitrates. Also, you didn't list calcium readings nor alkalinity. these must be kept in check for the corals you mentioned to thrive.

Also a possibility is water movement. how much do you have? My Euphilia paradivisa (frogspawn) likes enough current for the tentacles of each polyp to sway gently in the current. You should see the tentacles move quite a bit, but not too strong.

Ernie

 

[monkeyboy]

What exactly is good lighting? You could be frying them and not even know it. Also, what's the nitrate level?

 

[Clark]

I would say the salinity is definitely low 33 to 36 ppt 1.024-1026 good for most corals bring the salinity up somewhat slow but don't kill it with kindness either..I would also avoid over reacting on adding any types of suplements..the acclimation time can be a couple of weeks especially if the lfs kept their salinity at normal reef levels..work diligently to bring nitrate levels down the p03 most likely won't affect. You are going to need a method of keeping Calcium high but with the nitrate levels water changes should help handle that for the time being..cleaning any pre filters regularly will help keep nitrate down (daily or at least every couple of days) I personally just pull those filters out They are just traps for decay..IE - DAS pre filter and skimmer filter, also vaccum the detris out of the sump! You might want to think about dripping some kalk or the 2 part eas calcium system. This will also help to stablize the ph as well as adding calcium.

Boy you kindof got the whole opinion..sorry!
But that's my quarters worth!

C

 

[esmithiii]

the acclimation time can be a couple of weeks especially if the lfs kept their salinity at normal reef levels

I am not sure you need to do it that slowly- have you ever been snorkeling on the reef when it rains? Do it over several days and you will be fine.

Ernie

 

[Clark]

I am not sure you need to do it that slowly- have you ever been snorkeling on the reef when it rains? Do it over several days and you will be fine.

I was talking about the time for normal polyp extention can be a couple of weeks..

I completely agree that you should easily be able to raise the salinity over a couple of days..

 

[esmithiii]

Sorry Clark to misunderstand you. I agree completely!

Ernie