Yeah I only do the gas purge about 5 times at 30 psi. I will switch to the liquid/starsan purge. Also I'm going to take my FO hops and distribute during the boil. Going T try upping my sulfates as well. Brewing this weekend so will deff report back the differences.
Huge waste of CO2. Water purging is a huge waste of water, but much cheaper.
When water purging a keg it is important to completely purge the keg of all air. This means filling to the rim, installing the lid, and then continuing to fill through the liquid dip tube
with the pressure relief open and a gas QD attached. (Go Slow). Once you have water coming out of both, disconnect the gas QD, then shut off your supply water and then close the PRV. Alternately you could close the PRV and disconnect the water so long as you do them at nearly the same time. There is surprising amount of head space in a 'full keg'. Don't go through the efforts of a water purge and not use it to the full extent.
After the keg is full of water its time to purge. Start filling with CO2 and connect somethign to the liquid QD side. Either collect your starsan for further use or send it to the drain. For sake of time i like to run it at about 30 PSI for the first few minutes, then i'll ramp it down to about 10 to finish. You could go lower but it'll take longer to push the water out. Once the keg starts to sputter tilt it around for a few rotations to get as much water out as you can, then pull off the liquid QD. Wait a moment then pull off the gas QD.
If you are rackign under pressure you can use the remaining CO2 in the tank to purge your racking line! Vent most of the CO2 out through the PRV first. Then attach your racking cane to the liquid side - DO NOT DO THIS WHILE SUBMERGED IN THE BEER. Once almost all of the CO2 has pushed out, pull off the rackign cane from the liquid QD. Attach gas to the fermenter, insert the racking cane and apply a few psi of pressure (or whatever you like within your vessels limits). Once pressure is up, connect the gas QD back and the beer will star to flow. Open the PRV on the keg to allow back pressure to be relieved.
When the beer is almost done racking watch it carefully. The moment you see gas or trub getting sucked in rapidly close the PRV and pop the liquid disconnect off. Immediately pressurize the keg with 10+ pounds of CO2 to make sure it is sealed.
Done.