help! leathers and zoos dying, palythoa and gorgonians fine...

[TylerC]

I cannot for the life of me figure out why I can't keep some corals alive. my setup is as follows:

55 gal tank
4X55w pc 2 actinic 2 10k, 8 led moonlights.
photo period: led's all night pc's 14 hours a day
1 wdf3000 hang on back filter for mechanical filtration, within the past week started running carbon and phosphate reducer in it (thinking maybe there was some weird thing not being tested for in the tank that that could take out)
about 1 lb of rock per gallon, about 1/2 of it base rock 1/2 live rock from tbs. the dead rock was in a prior tank of mine, it was soaked in fresh water and cleaned thoroughly before being put in the tank, thinking this may be where some of the excess nutrients for the diatoms come from...
cpr backpack skimmer (pulls out a bunch of crap)
heater (keep it at 77.8 degrees, doesn't move even a degree)
no measurable levels of phosphate, amonia, nitrite and nitrate.
salinity 1.023-1.026 (yes sometimes get a little high)
ph 7.4
no phosphate
about 5-10gal water changes a month
dose phyto to the tune of a squirt a day/every other day
also put tigger pods in about once a month (for mandarin)

livestock:
5 hermit crabs
1 emerald crab
tomini tang
yellow damsel
blue devil damsel
clown fish
mandarin fish

corals living:
2 different palythoa types (one has a baby growing i noticed today)
1 gorgonian (kind of, i can see the skeleton at the base but its not deteriorated over the past month)

corals which have not lived (this list is longer)
2 batches of zoos (one kind of the palythoa is even on the same rock, opens up fine but the zoos haven't opened up for about a month, slowly withering away)
toadstool
1 condy anemone
and now a kenya tree that hasn't opened up up in a week

corals seem to follow the same pattern. they open up for a couple days then just stop opening. fish deaths have been non existent. tank setup since a little before xmas. interestingly had a hard time keeping macro algae alive. starting to grow a bit of it lately. have diatoms on all the rocks. which has gotten better since the addition of the skimmer, tang, and emerald crab (little over a month/two agofor the skimmer, 3 weeks ago for the tang and week ago for the emerald) salinity used to be higher, found out our hydrometer was measuring off, this has had no effect on the corals. temp used to be hotter (81ish) and have lowered this with no effect. I am stumped and I want to save this kenya tree before its to late.

the other thing i noticed was that a piece of palythoa had fallen off the rock and attached to the leather's rock, chemical warfare? it has been taken off but this was only a couple days ago.

help!

[oldreefer76]

Your ph of 7.4 is very low

[TylerC]

in the deadly zone for softies? how much kalk should i start dosing?

[gflat65]

pH is a little low, so try bringing it up. How long have the issues been happening? I'd suspect the phospahte absrber and carbon addition. Carbon is not a bad thing (I run it 24/7 in all tanks), but if a tank has unclear water due to organics, the carbon can strip the color fast enough to cause bleaching. Bad things can often follow the addition of phosphate removers, so I'd stop using that to see if the problem corrects itself. I have seen tanks that ran PO4 reducers that did great, but the initial period can sometimes be tricky. I've never run it, just read the horror stories amidst the successes.

For the zoas, check for nudis/spiders, too. Parasites don't seem to mess with Paly's as much as they do Zoanthus sp.

How old are your bulbs? Any painting in the house recently? Any aerosols?

[TylerC]

put the carbon/phosphate in a couple days ago at the same time and it hasn't changed the situation at all, it is the filter floss type of carbon/phosban. corals haven't been bleaching, just not opening and since it was so recent i tend to not think that would be the issue. water was never greenish either so it didn't clear up quickly or anything.

bulbs are under 6 months old i believe, 6 mos tops.

as far as nudis i haven't seen them but will look closer. i assumed it was something else since the leather's didn't survive either. I spend a good deal of time looking at the little thing up close.

issues have been happening since the first coral added. probably 3-4 months.

i will ask the girlfriend about cleaning (its in her house and she cleans lol) and aerosol but i haven't ever seen her using anything but a damp cloth to wash off the tank.

as far as the paint the only thing i can think of is that i made a mini sump type thing in the back of the tank where i hide my pumps/heater/temp probe etc... made it out of Plexiglas that was clear but i painted the back of it with black krylon (whatever the one made for plastics is) i let that dry for prob a week after painting and it hasn't since been flaking etc... could this be an issue?

[TylerC]

anyone?

[v13tfolife]

you should raise the ph. test your alk calcium and magnesium make sure they are right. and your ph should be around 8.1-8.4. and if u need to add to buffer the ph. i use kent marine superbuffer-dkh, this is a very good brand i only add it onces and my ph has been very stable around 8.3-8.4.