They wont let go of their arms when they die. The best way to check if they are is if they start "spewing" their guts out. That is a best way of knowing the star fish is doing ok or not. I would wait a little longer to introduce one brotha. And you are right, man are they putrid when they die. Dang, that smell is f'in horrible!
As you know, when live rock is covered with hair algae/algae, there are nutrients that are "locked/absorbed" by the rock itself. So it may take a long while before that is absorbed by the bacteria. So cooking out in the sun in a black container (remember, must be pitch black with constant water changes) might be the way to go. However, this should be the very last option since there are many available to you.
I think any system that are introducing a bacterial source via food (vodka biopellets) eventually will balance out. What I mean is the vodka that is being introduced into the system to promote a food source for the bacteria will eventually be ineffective (remember, vodka in the ocean is not natural). Why? The bacteria that absorbs the food source via the vodka to combat NO3/PO4 will eventually stop absorbing nutrients (NO3/PO4)--it has reached a balance. Just like a skimmer that no longer produces skimmate, the system has balanced and this happened to my system. This happens very naturally in nature as well as in closed systems where a balance has been reached regardless of how much more food source is introduced.
Since you are handy, try an ATS--algae turf scrubber. its very inexpensive and are very effective at combating algae as well as absorbing nutrients in your system. The big plus about an ATS is that it is natural!!! Algae of all type are found in the oceans including reefs and are symbiotic to a reef. Its just when we see hair algae in our systems, we go into destruction mode. Plus, you don't have to unplug or get rid of your skimmer.
My next system is going to be skimmerless and will have 2 ATS systems working non-stop. Here is some reading on ATS and you could type it in on google with tons of information on it. Either way, "cooking" your rock now should be the very last resort. Good luck and happy hunting brotha. If you have any questions, you know how to reach me!
http://reefcentral.com/forums/showthread.php?t=1977420
http://www.reefsanctuary.com/forums/...+turf+scrubber