S-L-O-W Leathers

I have a standard size 48" 75G with 20G sump / 'fuge DSB, LR.

The tank is swarming with mysis and 'pods, etc etc etc... It's been set up
for 5+ months but with water, sand and goods from 2 smaller 1 + year old
tanks.

ANYWAY,
when tax time came I bought MH lighting. It has only 2 175W MH 10Ks. Life
is exploding, Xenias, sponges, 'shrroms, zooanthids all doing great but my
leathers... closed up for 2 months.. some even rotted off their stumps
before showing their "feelers" again. now they are healthy, spreading daily
and doing ok... but not growing well at all (If at all).

I set up a 10G nano with 2x65W PC (1 yr old bulbs though) and the leathers
resume growth pretty quickly.

I can't figure out whats stunting them in the main tank... too much light??
water too clean? *scratching head*

I really enjoy the leathers can someone help me get them growing again?

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Art and Aquaria
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