Reactor fittings

[Delphinus]

I don't use those, but if I did, I'd use 3/8" tubing as I think that's the size that slips over the end of the maxijets, and then use 3/8" JG fittings on the canister. They might be a bit more obtuse to source but you should be able to get 3/8" to 1/4" NPT if that is the size the canister needs.

Failing that (the more specialized pushfittings can be hard to find sometimes) I would use a 3/8" to 1/4" reducer coupler (pushfitting or whatever) and basically 3/8" from the maxijet to there, then 1/4" or whatever size the canister requires.