[xoomer]

I have to agree with steve above.

You'll need to sell most of your fish (I think more than half of what you have). Sell the biggest and hungriest first.

Converting a tank from freshwater to saltwater is probably worse than starting from scratch and seeding it with established LR and LS. The beneficial bacteria you had in your fresh/brackish water will die causing a spike. In addition that many a fish would put tremendous load on the system that is already established, this is much worse when you are just starting and cycling.

Continue doing 20% but frequent water changes, add some carbon to your filter or in a filter sock next to your return.

You must get rid of all large fish, sell them soon or you'll loose them one by one. Do a head count everyday to make sure there is nothing missing decaying behind the rockwork. Feed once a day in the evening and much less than you did until now. It's ok to skip a day too.

Stay away from the tank thoughout the day except to do water changes. Your fish are already stressed and keeping your hands in or around the tank isnt helping them at all. It's only matter of time that one will break out with something and they'll stop dropping like flies only adding to the problem.

Also shorthen your photo-period or even almost eliminate it if you dont have any corals. With your tank cycling you'll only grow nuisance alge from now on; why add to the problem.