LPS not doing so well

I've had my LPS corals most of them for about a year now and recently, they all seem to be going through some really hard times.
My dented brain is completely dead, My frogspawn that was once huge is on its way out, my moon coral is showing serious tissue regression my scolys also had severe tissue regression. My bubble coral is the only one that seems to be doing well (Knock on Wood)...
In the past few months, the only changes I've made was becoming more diligent with my water changes (10% once a week). I only started doing more WCs when I started to notice that they took a turn for the worse.
Ammonia: 0
Nitrite: 0
Nitrate: 10
pH: 8.2
S.G.: 1.025
Ca: 420
dKH: 8-10
PO4: 0
Temp: 79F
All other corals seem to be doing fine, all softies and one millipora sp.
What could be causing this problem?

 

how old and what type of bulbs are you using?

CF bulbs need to be replaced every 6 months
MH bulbs - every 9 or so months
T5 - about the same as MH.

Also what do you have for water circulation?

 

Could you post you lighting and weather you have a skimmer, please.

Are you feeding your lps ?

 

Do you run carbon, and do you have zoas/chalices in the tank?

 

All good questions so far, but what about your Mg levels?

 

My tank is mostly LPS. If I let the carbon go too long without replacing, my LPS get weird.


Agree with all above posts. Also affected by bulb age and Mg levels.

 

Thanks for the quick responses.
I'm running 2x250W MH. About 5 months old. Odyssea fixture. All LPS are on the sand bed.
Sorry I don't have a Mg test kit as yet.
I haven't replaced carbon for quite some time. I'll swap it out now.
I do have a area with lots of Zoas.

Forgot To State: I do skim. DIY skimmer (Best Skimmer I've ever used)
I feed the corals by dispersing Cyclopeeze every 3 days or so.
And I'm using one Korillia 3 and the return from mag drive 12 for water movement.

I've recently started to see an outbreak of nasty hair algae.

Gonna get some NP Reducing Biopellets to see if that helps any.

 

What's your water source?

And you really need to get a test kit for Mg.

 

I make my own water. 50GPD RO/DI unit. Coralife salt mix.
TDS: 0
I'm working on the Mg test kit. None available in Trinidad I have to import it.

 

Need to test the Mg. Very important. IMO, most important test in an established tank.


Change the carbon about every 3-4 weeks at least. Don't let it go too long or it will not just 'stop' working but become 'counter' productive as it leaches back out. (or so I've heard)

You need to identify the source that is triggering the GHA outbreak. Pellets to help are fine, but only a short term band-aid.