but I wonder if I could raise the fuge up a bit to compensate? There would be water that bypasses the fuge underneath and around the sides. Is this ok?
It would more than likely be recommended
, the flow through the fuge is generally recommended to be much less of that through a sump.
Also if I use my existing water, could I just add some sand to the fuge and then add some plants and pods without disrupting my main tank too much?
You may want to "cure" the sand first, or use LS
. To cure it, put about 25 lbs in a bucket fill with SW
and add a raw shrimp. This will coat the sand with bacteria and make it settle much easier. If you add dry sand, I think you can expect a cloudy tank.