Planted Tank Guru
Join Date: Jan 2010
Location: Contra Costa CA
If it is too cloudy to trust putting fish in the tank (think of the gill irritation breathing all that dust!) you can try a couple of things:
Easiest: Add plenty of polyester floss to the filter. This will trap a lot of that stuff, though not all of it. You may need to rinse the polyester floss daily for a few days.
Almost as easy, but $: Get a micron filter. This will clear the water very quickly (I have seen one clear a 40-50 gallon tank in half an hour).
Much cheaper, a bit more work, but fairly fast: Drain the tank below the level of the substrate. Put a plastic bag or plate over the substrate and fill slowly. Run the water in over the plate or bag so it seeps into the substrate. If that still clouds, then do another water change. It might take a couple of partial fills and drains to get the water clearer.
Much more work: Remove the decor, plants, and rinse the substrate in the tank, stirring it as much as you can while running water in and out like a constant water change. Finally drain the tank and fill as above.