Corals acting strangely

[Mick Crawford]

I have an Aqua Medic Percula 90 about 70 gals with everything built in, skimmers, filters etc.

The tank is now 6 months old and all the readings are '0' or normal. Calcium is 224, magnesiun 1480. S.G has recently risen to 1.029 and I am correcting this gradually with water changes 10% per week.

I have currently got green mushroom corals and a leather which are very healthy, a bush coral which recently has not opened as fully as it used to and a pulsing xenia which appears okay. I also have a yellow button polyp but the fans on this do not come out as much as they used to.

But I have recently lost 2 finger corals after a temp rise while on holiday, it went up to about 29/30 C. Prior to this I put a hammer coral and a slipper coral in the tank. Both appeared healthy when I bought them. The hammer coral lasted about a week and then shrunk into into its skeleton and has never been out again, the slipper coral lasted about a month but appears to have given up the ghost.

I have asked local dealers who all came up with different answers, I did try marine 'Snow' coral food and I have added a phosphate bag to my filtered water in a seperate area at the back of the tank. Nothing seems to make a difference.

Can anyone help or is my tank just too young.

Mick

 

[Anonymous]

In case no one has said this yet Mick...
:welcome:

The elevated SG would be my first concern, and I'd lower it quicker than the 10% a week change by adding more freshwater than is evaporated daily and pulling out the excess. For example, if the tank evaporates 1 liter a day, I'd pull out an additional liter of saltwater from the tank and add 2 liters fresh. Also, during water changes you can make the SG a bit lower than the main tank but must add the makeup water slowly so as to minimize the shock.

Secondly, the calcium level ideally should be between 400 - 500 mg/l. Do you test for PH and ALK as well? if so, what are the readings?

What type of substrate, if any do you have and what kind of lights?

 

[Mick Crawford]

Thanks for the reply and for the welcome - the PH is 8.4 and alkalinity on my test kit shows normal to high.
I have aragonite substrate and 150w halide lights.

My apologies, calcium reading was 424 not 224.

I also forgot to mention I have 2 yellow tangs, two Pyjama cardinals, a clown and a blue damsel. All appear absolutley fine. I did lose all my turbo snails but put this down to the temperature. My cerith snails are fine, presumably because they burrow beneath the sand.

 

[Anonymous]

424 is MUCH better! I'd just stay the course for a while, lower that SG and hope things perk back up. You may want to do greater than 10% changes, as with your fish the bioload might be a bit much for a newer tank. You did get all the decaying things out of the tank, right?

Hopefully someone else will chime in with another idea.

 

[Mick Crawford]

I am very grateful for your help. By the way when would an experienced aquarist consider a marine tank to be established for the purposes of inserting hard coral?

PS love the changing face icon

Mick

 

[ChrisRD]

Personally I prefer to give the tank a few months (minimum) before putting any stony corals in.

 

[Anonymous]

Personally I prefer to give the tank a few months (minimum) before putting any stony corals in.

As usual, I agree with ChrisRD...the more time to stabilize the tank, the better.