i am having a problem with pink slime esp under the stairs. bacqua pool- above ground 18'. changed sand...used assist....used pink away?...it still keeps on coming back. is my best bet to hang in there and add nothing at closing and switch to economical chlorine in the spring? i used chlorine in my other pool which was crushed by a tree by isabel- i had no problems...is the pink stuff an algae or a bacteria?