For those still giving the tank system a chance ill share.what ive learned. Yes refilling.with syringe.is.better than removing.the cap, that seems more prevelant with the plastic caps, order sin silicon caps. Refill with syringe, the.trick is to get a blunt or dull syringe, those are legal, though I haven't had any luck in NY. You can get hooded bottle caps with syringes in them. Also its safer to have a blunt rather.than Sharp.
Another trick I found but never tried. Find a dull syringe with a 2.7 mm external diamiter. Use that and punture a fresh silicone cap with that first. The needle in the atty is like 3mm which means it will fit extra tight and even pull upwards a little when u inseert creating a perfect seel.
I gave up on tanks cause i had 2 tank attys blow after 2 days use. im sure ill givr it a go again, but gonna delve into time tested drip and cartos first. also wanna try the MAP style of tank.