Wall Hammer Coral Receeding

[Dendrobates]

A friend of mine has 3 wall hammers of different colors and origins in a large display tank and every one of them has the exact same recession. It's on one end, about 1" in length total where the coral has died off and left a stark white skeleton. The remaining coral portions do just fine and eat mysis regularly and maintain decent coloration. I've also lost some LPS in this tank like open brains and octospawn, they never seem to open up after shipping and slowly wither away.

tank parameters (all with API liquid tests)
90 gallon display, 20 gallon sump, corallife skimmer

temperature: 79 F
ammonia: 0ppm
nitrite: 0ppm
nitrate: 5ppm
calcium: 480ppm
alkalinity: 300
pH: 8.0
SG: 1.025
Lighting: 2 x t5 bulbs (10k, actinic) and a fluval LED full spectrum strip

Fish (2 onyx clowns, 1 mandarin, 1 sailfin blenny) are fed daily, corals are spot fed 2 x weekly.

I know the test kits need upgraded, but does anything jump off the page as far as out of wack? All the softies, pagoda cups, whiskers, gorognians, clams, etc do just fine.

Thanks in advance,

Derek

 

[chrisfont23]

Flow not listed... what are you using and how much flow do they generate?

 

[chrisfont23]

I know the test kits need upgraded...

Such a misconception. I have 3 FW tanks, 1 SW and 2 outdoor ponds. Use API liquid for years. Never an issue. Just keep up w/ expiring products

 

[Dendrobates]

There's 3 power heads in the tank but the return pump from the sump is weak. The powerheads are aqueon 950gph, and two 300 gph pumps. The LPS are in a gently flow area of the tank, enough to sway the coral but not blast them directly.

 

[RA]

It seems like your lighting is really weak.

 

[SUMMERS]

Have you tested for PO4?

 

[Dendrobates]

We did a phosphate test on it and it reads between 0-0.25 ppm, not extremely accurate

 

[Dendrobates]

The full spectrum LED light is being replaced with 2 more t5 ho bulbs today, so that will make it 4 x t5 ho

 

[RA]

The full spectrum LED light is being replaced with 2 more t5 ho bulbs today, so that will make it 4 x t5 ho

I think that will help. I have to say that I'm surprised that your clam is OK.

 

[Dendrobates]

They are ORA squamosa and derasa clams

 

[Dendrobates]

Checked it out today, the largest green hammer has taken back over the bare skeleton, the purple hammer has stopped receding, but the smaller green hammer still seems to be losing polyps. I know results are not instant, but it's nice to see a little positive progress.

 

[SailAnnapolis]

I've got the same problem. This pink hammer is about 5 inches wide. the corners have loss flesh/polyps about an inch inward from each corner. It was placed in the tank a week ago. It's on sand bed now. I think too much flow could be going across it or the light was too high. I turned the light down but I'm still not sure what it is. phosphate is .025 to .05. hardness 9, ammo and nitrite zero, 1025 salt. The lights are powerful Pacific Sun led's turned down to 35 percent They are same power as radian pro's wattage wise.