What Can I Do Now?

This 90 gallon has been up for about two months now. I moved up from a 55. The 55 was up for five years (fish Only), I started adding a few cheep corals within the past year. Then moved up to the 90. I saved everything, sub,water,lr,ect...

 

that might explain your phos, if you reused your sub, hopefully you rinsed it really good.

 

No I was told not to

 

A 55 to a 90 is a big step that requires adding a lot of different things. How much substrate do you have? Rock? Flow? Sump/fuge? Stock?

 

Fish: Sailfin Tang (Large), Valamingii Tang (med), Kole Tang (med), Yellow belly Regal Tang (small), Tomato Clown (med), Scotter Blenny (med), 6 line Wrasse (small), Green Brittle star (large), 2 cleaner shrimp,

 

75lbs LR, Wet/dry bio balls, Koralia 4, 790GPH return pump, seaclone skimmer

 

1 1/2" to 2" of crushed coral. Had to add one bag when I made the switch.

 

Well you definitley need more rock and flow. 75lbs is about half the rock you need. Aim for about 150lbs. Go with base rock as the tank is already running and you don't want to create more of a cycle than is already taking place.
Right now you have less than 2000 gph of flow (depending on your headspace and routing of your return line). For flow you need about 3600gph running through that tank. This will also effect the filtering capabilities. Non-aerated stagnant water will collect toxins and wont support the chemical breakdown of the wastes.
How much room do you have in the wet dry? You are going to need a sump/fuge capable of holding a monster skimmer. 4 tangs in there is really pushing your luck. HOB stuff is not going to cut it.

 

I'm looking at the Red Sea C-skim 1200 to replace my seaclone. How big of a return pump do you think I would need? I have 4' of head.

 

Thats quite a bit of tangs. thats a lot to add for a 2mo old tank. When I had my first tank, it had crushed coral and my param were always off. I switched to sand and havent reallly had any problems. And as I ended up having lots of live rock I ended up getting rid of the bio balls and went Berlin.