Your set up for this is quite unique. It seems like it will work but you never know untill you try i guess. If you do end up keeping moon jellies and feed them brine, make SURE you keep up on your cleaning/ syphoning. If you leave un eating brine in the tank for to long they will cling to the sides and become hydoroits, (sp), they can/ will dismember you jellies. If I feel motivated I will bring a camera with me to my internship and take a few pics of their setups on their jelly tanks. Have fun with the jellies though.
-justin
-justin