star polyp trouble

[p00num3lli]

ok, i have two beautifull star polyp colonies (1 red, other is pink) both have all the sudden died, over about 3 days.all other corasl are fine "cup coral, zooanthids, mushrooms, yellow polyps, candy cane, and hammer coral, all is fine and the fish.

nitrite:0
nitrate:20 (were alot higher) acually got the poylps when nitrates were 90, so i dont think trates are the problem)
ammonia:0
ph:82
salinity:1.025


all is fine,BUT... i saw this wierd flat oval scaly like crature crawling on the star polyps, its almost half an inch long. no clue what it was.

im also thinking maby it could have been from hurracane (loss of electricity) we had my tank running for 1 hour, then off for like 5 hrs, then ran another hour, and so on, just to save gas.

maby that was it, but ud think my more difficult and harder to keep corals would be doing this, no the hard and tough star polyps (well i think there tough)

and maby also, i recently got a skimmer about 1 month after the corals, and its been about 3 months from then. ive heard some corals die when u get a skimmer, because the water is to clean

i do water changes 1 time every 3 weeks, or 2.

thanks