If you siphon gravel regularly and do frequent waterchanges, you can use gravel in a saltwater tank as well. It's just more work.
I prefer to not have undergravel filters in saltwater tanks. They can be used if you run them as Reverse Undergravel Filters but I really don't see the need. If you have an efficient skimmer, you likely don't need the airstones. Watch your pH level and that will tell you whether you need them. Most people actually prefer to aim a powerhead at the surface of the water rather than using airstones because airstones cause so much salt creep (when the tiny bubbles pop). _________ Curt  |