Looking for some plumbing help

[d3rryc]

I need some plumbing advice, plz. I picked up a Mini-Jet to run my Knopp C calcium reactor. My question is how best to mate the 1/2" Mini-Jet outlet to the 1/4" calc reactor inlet, preferably with a ball valve in between to fine-tune the flow rate into the reactor.

Thanks!
Derry

[StevenSeas]

how much space from the mini jet to the calc reactor? all hard plumbing or flex tubing?

[d3rryc]

Space is tight, 6" or less, and the expectation was to use flex tubing.