Hmmm quite a challenge there with that jelly. I have kept a few outside of the home aquarium setting and consulted with many public aquariums that keep them as well. The general consensus is that they are very hard to keep alive for long, especially not knowing the diet/conditions that a particular species favors. As most species are effectively planktonic, they are often found far from where they thrive (ie washed up on beaches, in shallows etc).
here are a few more thoughts anyway since you are asking. I am speaking in general terms as I am not familiar with the species you have there (not a common one that aquariums I have worked with keep).
Most jellies need a lot of food in the form of enriched zooplankton. The tank has to be literally saturated with food as they are passive feeders (they need the food items to bump into their tentacles in order to feed). Lots of cyclopleeze is a good start for most jellies though they may need more than that for long-term survival. Selcon has been used to enrich cyclopleeze by some, with uncertain effects. I have seen seemingly healthy jellies die with full stomaches of cyclopleeze so there may be something missing from the equation.
Jellies are very delicate and a tank with enough flow for tthem invaribly poses a risk with them getting sucked into the intakes (as you have already seen). These injuries are pretty hard on the animals and one or two such impacts on an already stressed animal could be fatal. Most specialists keep them in species tanks called Kreissels which are carefully constructed to move water without presenting any intake hazards. There may be info on RC about them or just do a google search and you will find plans for making a cheap one (the larger commercial units run $10,000s).
I would make sure at least that I isolated the jelly from the rest of the tank inhabitants as their sting can be deadly (or at least annoying) to corals and some fishes.
Jellies need incredible filtration as their food needs are so high. Running a dedicated skimmer or two is recommended. Larger tanks are key here too with most aquariums that are successful keeping tanks in the 1000-5000 gal. TSV range. Obviously not practical for you but maybe a 50 breeder or something?
Well, hope this helps you out a little bit.
