The filter is a Magnum 350 Pro. It uses carbon filtration. I figured they were mostly for FW
because of all the shops i've been to have told me about a proper setup and some of our family friends have "proper" setups. Then again, their garage houses the water tanks.
There are no powerheads?? Not sure what that is. The filter has an in/out on the side and two bio-wheels up top that create a current.
We have about 20-26 lbs of crushed coral as substrate. It forms an inch from the bottom up. We have a single 10 pound live rock. No coral reefs. There's a SW
safe "broken" vase, pieces of dead coral but not crushed, and a medium conch. It's a SW
tank with live rock and fish.
We actually had 20 damsels. 6 three spotted, 6 four striped, and 8 yellowtails. And also 4 hermit crabs that were clung to the rock when we bought it. 20 does seem a bit much, but the fish are small and barely took up space. Obviously ammonia is a factor, but it was controlled.
The lights are on at 11 or 12am, and get turned off after 6-8 hours. It controls the algae. And we feed them flakes every other day. Sometimes we give them live food and frozen shrimp, but these make a mess no matter how small and the damsels weren't too fond of them.
Right now there are two striped damsels, 1 spotted, and 6 yellowtailed damsels. The rest died. Newer fish of the same type were doing ok for the past month. We bought two blue damsels that were all blue and were the first i noticed to chew on the rock. None of our other damsels chew on it. Then these two died with swollen mouths. When we bought three foxface, we noticed they immediately went straight to the rock and started chewing on it. One was dead the next morning with that swollen mouth. The other died next day without any symptoms, just instant death. And the third lasted a week before its mouth swelled and died.
We wanted newer, expensive fish to add but after those three foxface died, we decided to change the water with water from our LFS
because they recommended we do that.
Well last week we did and that's all that happened. All our healthy "old" fish are now dying of the same thing. A reddish algae has formed on the filter basket, conch, and dead corals. A yellowish algae has formed on the top of the substrate and only in the areas where light hits.
I'm not sure what else to say. The feeding is the same, hours for lighting, and clean up is all the same. No change except water. We always test weekly and nitrates/nitrites are not at 0. They're low not high. And ammonia has always been very low but never at 0. No chlorine, 1.024 of salinity, ph fluctuates from 6.5 to 7.9, carbonate hardness is around 120.