Your algae now sounds like cyano
bacteria which is normally a sign of high nutrients and low flow (sometimes). To combat cyanobacteria I recommend water changes (siphoning out the cyano
) with RO
water, cut back on feeding, increase or start skimming and increase waterflow over the effected areas. It can be a long battle, but one that can be won with perseverance.
To my knowledge there is very little thant actually eats cyano
, queen and horse conchs are about all I know that are noted to eat it, and then just off the sand bed.