[pogodzib]

Welcome to Reef Builders Edd

1.) No a sump isn't necessary, but it does add water volume which makes a tank more stable and gives you a place to hide some equipment.

2.) Having a different tank (a q-tank that you can use for all future purchases) to hold them in while you set your tank redone would probably be prefered (if you set it up correctly) or a close second would be to see if your LFS will take them back and hold them for you until your ready for them.

3.) If the sand is full of detritus (waste) then you'll want to remove all of your sand and replace it with new sand. It would be much easier to do it now then later once your tank is full of fish, LR, etc... and you are having algae or nitrate problems. Water changes alone won't solve your problems if the sand is full of waste. As for water, RO/DI water is highly recommended for reef tanks due to the strong lighting. Poor water quality will cause algae issues, along with other issues that could affect your fish and coral success.

4.) All pet stores that sell fish supplies should sell test kits. Salifert, LaMotte, and Elos are good brands. Just make sure that you buy test kits that are made for testing saltwater. Freshwater kits will not work.