i've stopped using water in my bongs, now i just use ice... i seem to get much less blazed when i have water in the bong, or it takes more to reach the same level, so i just put some ice in to cool the smoke (works remarkably well, even better then ice water could work, almost makes you feel as if you're smoking menthol, but without the mint taste) crushed ice is even better...

as for hot water and ice, i do believe he's talking about a bong with an ice catcher in it (kink in the neck that won't let something like ice cubes fall all the way down) you put hot water in first, then drop in a few ice cubes.... hot water filters the smoke, then as it passes the ice it cools it down.