[tang daddy]

Regular FW don't harm corals but they get out of control in plague proportions and you'll find them pearching every where on the lr sometimes they go onto corals sheding the coral of light that's when it becomes a problem. FWE works but only at a high dose keep in mind that when a mass amont of these FW die they can pollute your tank quickly, Hence a 50% WC needed after the use of FWE also carbon filtration to remove FWE so leave them in your tank if you don't care. But also realize that when you want to rid them you'll spend more $$!