58g been running for 16 months. All normal tank parameters are ok. Double checked by lfs. Just added a DIY 20g long sump. Used acylic and pvc (1/2 inch water sprinkler type) from home depot. Used the GE silicone II window and doors as I've seen recommended. Two days after hooking it up xenia, fungia, and star polyps clamped up and started receding. Ammonia came up to about .25. I added a cannister filter with carbon only. Should've but didn't do a water change. No water mixed. Also lost a yellow tang, and about to lose a coral beauty. Bodies look sunken in (like starved) and fins ragged. Other fish include a royal gramma, flame blenny, and false percula. Also have 2 cleaner shrimp and a few snails/hermit crabs. All seem ok. Been fighting bryopsis or hair algae since forever. The only change recently was the addition of the sump. I probably didn't do a thorough cleaning of acylic and pvc. Any ideas of what I need to do to get rid of this problem? Will I have to tear down and try to disinfect live rock/sand also? I use R/O water from a grocery store machine.