Saltwater fish tanks

Thing to remember with a salt water set up is you are more or less playing God. You are creating a universe for creatures to live in. Fresh water is far more forgiving, the trade off is the fish are not the same. I would never do a tank under 125 gallons, nor would I ever do one with out a sump again. Having the sump dictates what kind of tank you can use, as it needs overflow boxes. The larger the tank the easier it will be. When you have 300 gallons of water things are a lot more forgiving. In my 125 I had an eel that lived in the sand. I wanted to put some burrowers in but could not because there just was not enough room. In the 300 gallon I had an eel and a couple of burrowers (don't remember the name) because there was enough room for them all to get along. The burrowers were 2 of the 3 deaths that we had, they did not die from my care they died because as well as burrowing they were known jumpers and that is how they died, they jumped out before I had made the lids for the tank. Part of playing God is you have to have an understanding of how the universe works. And at times you may have to sacrifice doing something because of a disaster in the universe. Again, this is where more water is better, as things do not happen as quickly in 300 gallons as they do in 30......