 Sand Sifting Star losing legs
I bought a SSS about 8 months ago and it was fine up until a month ago. At that point portions of it's legs started turning white and falling off. Its down to 2 full length legs and three stumps. I also have a tiger serpent star but its legs are fine. Has anyone heard of this before? Anther question is what would cause black dots, as well as something that looks like mold, to form on a scarlet cleaner shrimp? After my SCS molted three months ago this stuff showed up, and after each molt these "marking" showed back up. Then this morning I found that my SCS had molted again, but this time The Molted skin and SCS itself were stuck to my power head  , just wondered if the power head may have been to strong for the shrimps fragile new exo or if these spots could have part of the cause?
Thanks for any advice or experiences that you may have had with these items.
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75g (7/04), 4x65watt cf, ASM G3, 65g refug, turbo-twist UV sterilizer, 2 koralia, Quiet One 3000, 123# LF, solar fairy wrasse, blue hippo tang, banggai cardinal, green chromis, O. clownfish, royal gramma, yellowheaded jawfish, serpent star, xenia
29g (9/04), 65 watt cf, coralife needle wheel, wet/dry, 1 koralia, 25# LF, coral beauty, b/w percula, yellow watchman
75g (8/07) 4x65watt cf, ASM G2, 2 koralia, 30 g refug, Quiet One 3000, 100# LF, Blonde naso tang, frogfish | 
