I hate to break it to you but more or less the only thing for algae suppression in a tank with aggressive fish is you! In my aggressive I have these crowned snails that last only cause they are very camoflauged and only come out at night. A couple have had there shells chewed on but they are layered so whoever did this gave up. My Red-Starry grubs the sand but now as well hides all day until night. Again on of the Trigs was trying to get him and when they couldn't they started to bite pieces off his shell in order to get what was inside. As soon as he had a break he took off to hide under a rock; the trig comes over sideways shoves his snout under the rock and drags the poor little SOB back out into the open. So if any cleaning crew does last it's only because they hide in the rockwork during the day and come out at night. If you want it done right and clean, I suggest you DIY.