BRS media reactors - input from owners please

[gregzz4]

Do you run a single or double BRS media reactor ?
If so, do you have issues with air getting into your canister(s) over time? That is to say, does the level in your canisters drop ..... ?

I've bought some Aqua FX single units from J&L and am having issues with the water level in the canisters dropping over a matter of hours
I've double-checked all hoses and gasket/o-ring mating surfaces to be sure there is contact/sealing happening

I can't figure this out for the life of me

If I can't solve this issue, I'm going to buy the BRS ones if they work better

Thanks for your help