Blasto receding help

[Koralliono]

This blasto has been receding in the shape of a pie piece. The first photo was taken in July and the second photo was taken yesterday. Anyone know what causes recession to occur in such a defined triangular shape? I haven't seen any pests on it.

 

[Reeferdood]

Please tell about your setup and water parameters..

 

[Koralliono]

138g w two Hydra 52HD.
1.025, Alk 9.3, Ca 450, Mg 1350, NO 3, PO 0
Hydras on 10hr photoperiod incl 2hr ramp up/down; max intensity 85% for UV, V, B, RB; 18% W; 10% R and G.

 

[Reeferdood]

Hmmm, is it in a high flow area? They don't like a lot of flow...

 

[Koralliono]

No. I have it on the sand near the front of the tank left of center. Two MP40s run on the ends but are higher up towards the water line. The return pump outlet is a Y-fitting that dilutes the return pressure.

 

[Reeferdood]

Well..
Vortechs are powerful, I use them as well...
have you tried ever moving it?

 

[Koralliono]

I run the MP40s on a program varying from 20-80% intensity cycling through reefcrest, lagoon, nutrient, and tidal modes. The powerhead on the right side is on anti-sync of the left side. Is that too strong? The tank is a reefer 525XL. I've had problems with some chalices and favias as well and haven't been able to identify the culprit.

 

[Reeferdood]

Have you ever moved it to a low flow area?
I'd try that first... it doesn't look like something is pecking at it to me...

 

[Koralliono]

I will move it. But given I'm having coral problems in other areas of the tank as well, do you think my powerhead flow program is too strong?

 

[Reeferdood]

It really could be something simple like that.. most softies like less flow IMHO

 

[Reeferdood]

Well?
Did you move it?

 

[Koralliono]

Yes I moved it and turned down the power heads.

 

[john.m.cole3]

Ok, a blasto is lps not softie. Regardless, both need some nitrate and phosphate. You dais yours were at zero. What test kit ate you using?

 

[najer]

I would say flow too, quite strong from the right in that last pic.