Ok, this is gonna be pretty long so hang with me. The good news is snap caps can be made. Bad news is it is a lengthy process AND you will have to remove your caps each time. First step: buy a set of slix nipples or track of the wolf stainless replacement nipples. Keep your factory nipples to make your snap caps. Make a jig to hold nipple.make a jig to hold nipple. Just a plate threaded to hold nipple.put nipple in jig and slip on fish tank aeration hosecut hose flush with top of nipple and remove cut peice for later use.use an end mill and cut .060 off of nipple.put plastic sleeve on nipple.fill with rtv silicone.wipe off excesswipe off excess and allow to set up for 24 hrs. Put in cylinders and enjoy. The plastic will eventually split out. Just rip it off and put on a new one and refill with rtv.