Maroon clownfish is sick, yellow tang has died

[Finzo11]

Set up my 90 gallon tank about 5 weeks ago. Used 90 lbs of cured live rock from an established tank to cycle it. Coflakeife salt and Carib alive sand were my choices - 80lbs of the latter for a 4 inch base. I've got a Megaflow 3 sump with a Rio 2500 watt pump pushing 594 gallons/hr, and a Coflakeife Needle Wheel Protein skimmer at 125 Gallons/hr. Also running a second powerhead in the tank, cycling about 294 gallons/hr. Initially used tap water and added Prime Day #1 and Stability daily for 7 days. Got Chempure and Chempure elite filter pads in my sump, and I removed the bioballs.

After the cycle, I added a Dwarf Lionfish, Maroon Clownfish, and a Yellow Tang. Yeah, I know - no quarantine. Diatoms showed up about a week ago, around the same time I added a 9W UV filter to my sump. Since then, I've added 10 Black snails, 10 blue leg hermits, 1 Red Leg Hermit, 4 Turbo Snails, and 1 Nassarius snail. Been testing SG, pH, Ammonia, Nitrites, and nitrates almost daily for a month. My parameters are - Temp 78 degrees, pH 8.3, SG 1.020, 0ppm Ammonia/Nitrite and Nitrate.

Three days ago, I visited a local aquarium and was told I should be testing for alkalinity and Calcium, and using a buffer daily. Did that, and my results were DK 7, Calcium 460. Added the buffer... and the next day, my Yellow Tang died. Now my Maroon Clown has white spots on his side that look swollen. I retested all my parameters, and they're all the same. Did a 25 gallon water change today. Any ideas? Is this Ich?

[fleeton]

I think the first thing to look at is water flow. The sump pump's actual output is probably around 400gph after head pressure losses, and if you're using a Maxijet 1200 for the second powerhead, it's probably only doing around 200gph with a partially clogged inlet strainer. That's only 600gph total in a 90 gallon tank - not a lot of turnover, especially if your surface agitation is poor. Are your fish breathing hard or acting lethargic?

As for posting pics, try using Photobucket - it's what most people use. You can host your pics there and then link to them from the forum. Just copy the IMG code under your thumbnails and paste it into your post.

[talonix]

I'm with you on that, I wouldn't have added a Yellow Tang so soon either. I mean, 5 weeks in is pretty early for such a sensitive fish.

[zenoxa]

I'm gonna agree with fleeton here. Bad stock or shipping stress could be what took out your Yellow Tang - it's definitely possible, especially since you didn't quarantine them.