I used the Fluval 88 for a little while, it works ok and is surprisingly easy to adjust but the cartridges will bleed you dry.
There is hope however, what I did is buy a fitting at Home Depot, a Watts brand A-182.
This is a 3/8" Flare x 1/4" MIP half union.
It will thread into the Fluval regulator/needle valve and the other end can thread into a paintball ASA adaptor, similar to this one but way cheaper on ebay
Then you should be able to use the Fluval regulator/needle valve on a paintball tank which is obviously much much smaller than a standard reg/cylinder combo.
One thing to note, I have not personally done this yet so I can't guarantee it's performance but I have seen it done online several times so you won't be pioneering anything.
Alternatively since I think you are in Canada, you could go to Princess Auto and see if they have any Jac-pac kits. This is a regulator designed to work on paintball cylinders, it's nice and compact and works great, all you need to do is remove the quick connector and add the post body kit of your choice. Princess Auto near me sells the Jac-pac for about $30 and it's well worth the money if you want to do paintball sized CO2.
I'm told that Lowes in the United States sells a similar kit but I haven't seen it in Canada.