I am new to this hobby. I bought a 400 gallon saltwater tank. I have a sump tank and a protein skimmer. I also bought 250 pounds of dry live rock and 160 pounds of live sand. I put two cat sharks and two sting rays in it. I cycled the tank for a month with some some damsels. My levels went high and came down so I was told my tank was good to go for the sharks and rays. Boy I was given some really bad advice. Everything was good for a week. Then my fish stoped eating. I checked my levels and everything was way high. I bought 20 pounds of ceramic rings, 70 pounds of live cured rock, and 2 buckets of matrix (the buckets are 4liters each). I also bought enough bio sipra to treat the tank aswell. My levels came down enough my fish are eating again but still a little on the high side. I have 3 marine pure blocks coming in the mail should be here on Sunday. Is there anything else i could do? Or is it just a wait and see and hope I don't lose any fish?