co2 gas lines

I got my keezer setup with a 3way secondary regulator feeding three kegs. I also split the line from the co2 tank regulator to the secondary and put in a tee to feed a keg for root beer.

When I carb a keg, I put the gas on the out side of the keg so the co2 filters up through the beer. Is this the way everyone else does it?

Also, when doing this, I get back feed sometimes from the keg into the gas lines. Has this happened to anyone else before?

Say, for instance, beer were to run back into the secondary regulator, can they taken apart and cleaned?

There is no reason to do it this way, the myth that beer carbonates faster by being bubbled up from the bottom is just that, a myth. Why risk ruining a perfectly good regulator.

check valves will stop beer from getting in your reg.

its only advantagous to carb through the Out post if you install one of those bubble wands first to diffuse the CO2.

gas dissolving into liquid is all about contact time and surface area. big bubbles of CO2 don't dissolve that much faster since they rise to the headspace within seconds.