What is causing my strange coral behavior?

kylie d

New member
I have a 20g Long sw reef that has been running for about 2 months now. Its residents include:

2 clowns
1 cleaner shrimp
1 peppermint shrimp
1 emerald crab
2 astraea snails
1 nassarius snail
3-6 blue legged hermies
small kenya tree
pulsing xenia

It has a bakpak reef ready skimmer and Sundial USA 4x24watt T5HO actinic/10,000K light (with lunar lights). Also about 20-25 lb of live rock and 1-1.5" sandbed.

The problem is with my two corals. For about a week now, the kenya tree has been constantly a pale purple color and very small/tucked into itself. At first it was only slightly as if one of my shrimp had made it mad but now it is constantly like that and getting paler. It does hold itself up (no slouching over) but is getting more blue and less pink/purple.

The Xenia is acting sickly as well. It stands up on its own and isn't shrunk up like the kenia tree, but its "arms" and "hands" are skinny and fried looking. The "trunk" is very pale pink, the "arms" are slightly more pink but very thin, and the "hands" don't ever pulse and are curled up and purple. Normally, if the xenia gets mad from something pesters it, it turns completly purple and sucks up its arms, unlike now.

My parameters have been relatively consistent over the past 2 months:

Temperature: 79
Calcium: 360ppm
Kh: 10 (dropped from 11 in the past two weeks)
Phosphates: 0.5ppm
pH: 8.0 (it had dropped from 8.8 to 7.9 two weeks ago but is very slowly/safely climbing back to normal)
Ammonia: 0
Nitrite: 0
Nitrate: 0
SG: 1.025
*these results from two days ago
I just did a 25% wc at the suggestion of the fish expert at my lfs.

The only real changes to my tank in the last week has been a new heater, which is working well, and starting a new type of salt. In last weeks 10% wc I used coralife saltwater mix with RO water instead of Instant ocean I got when I started up the tank.

So, any ideas as to what is causing my corals to act sickly? What should I be doing to help fix it?

Please and thank you for all your help,
kylie d

Shane Hoffman

New member
Phosphates are a bit high. How old are your bulbs? Your tank has only been up 2 months but how long have corals been in?

Most xenia are fairly hardy. I know the whiter pulsing xenia are not as hardy as the rest.....I wouldnt think the salt is the culprit but it could be. Your corals dont have much of a calcium demand but 360 is low.

I know this isnt much as far as help...just some thoughts and observations.....

kylie d

New member
I have a new phosphate reactor set up but its only been running for a few days and needs its gfo changed but I didn't want to upset my corals more than they already are.

The kenya tree came with my live rock and the xenia has been in my tank for about a month.

Thank your for your thoughts. Anything is helpful at this point