Ok here is the story...We have had our saltwater tank up for about 4 years now. It was crystal clear all the life was healthy as can be and there was no algae to be seen. Then about 2 years ago my family went on vacation for a week. We had our neighbor come in and feed the fish every day and we instructed her how to. When we come back everything looks fine and dandy but 3 days later BAM, full on algae bloom. Within a week there wasn’t any swimming space just algae. So we figure the neighbor overfed. It has killed almost all our fish, coral and clams since then. We have performed countless intense vacuum jobs, tried all kinds of chemicals and things and nothing ever works. We turned the lights back to 5 hours a day for more than a month and with no avail just sickly looking coral. We tried introducing a different kind of algae that is supposed to be harmless and is supposed to take over all the green but that didn't work. We tried introducing different fish(algae blennies, tangs, lettuce nuttibranchs, and countless snails and crabs). Nothing every works.
The tank is about 160 gallons, we have 2 protein skimmers, one big filter which takes out all kinds or organic and inorganic junk, including phosphate and ammonia. Currently there are 3 tangs (blue hippo, naso, and yellow), a couple coral and a clownfish, and about 400 lbs of live rock. We have aboslutly no phosphate, nitrate or ammonia. The water quality is pristine, but the algae is everywhere. Other stuff--we use R/O water, temps range from 77 to 80, 400 watts of lighting. Any help would be greatly appreciated...we are desperate and about to give up on the tank altogether
