Starburst monti cap with brittle edges

swannyson7 · Sep 26, 2011

I acquired a piece of the Reeftech starburst cap a few months ago as a 1/2 inch frag and it has grown pretty steadily. It completely encrusted a 1.5" frag disc and now it's starting to plate. The only problem is that the edges are extremely brittle. Almost to the point that the edges dissolve in my hand if I touch the frag. All other monti caps are fine and I'm wondering if anyone has had a similar experience or knows what could be causing it? Based on all of my searches, the only thing that I've come across is an issue with too little flow, but it's in an area with a descent amount of flow, so I'm not sure what else to look into. Here's a list of parameters:
Temp: 80F
Salinity: 1.026
pH: 8.3-8.5
Nitrates: 0-5
Phosphates 0.01 (hanna calorimeter)
Calcium: 440
Alk: 8 DKH
Nitrites: 0
Ammonia: 0
Magnesium: 1300

m and m · Sep 26, 2011

Alk and mag are low for me. and that po4 is most likly off if your not using a photometer.

gar732 · Sep 26, 2011

Mine isn't in an area with high flow at all and I haven't noticed anything like that.

swannyson7 · Sep 26, 2011

I realize that the PO4 is probably not that accurate, but I don't have any issues with algae and I have good coloration in my SPS. I could try raising my Mag, but would this cause the issues I'm seeing? I'm reluctant to boost my alk because I'm running a ULNS, and I've read that high alk levels lead to problems in ULNS systems. As I said, all other monti caps are fine, it's just the starburst and only the new growth. The existing growth is nice and solid, but the new growth almost turns to sand when you touch it.

swannyson7 · Sep 26, 2011

gar732 said:
Mine isn't in an area with high flow at all and I haven't noticed anything like that.

How big is yours at this point? Mine was fine when it was encrusting on the tile, it wasn't until it started to plate that I noticed an issue. Coloration is still fine and there are polyps in the fragile part.