Your pads should be soaked before you install them, and clean water is just fine if you so choose. If you’d like to sanitize your pads and / or the whole filter system, use your sulfite cleaning solution, with or without acid, however you make it. As long as you saturate the pads prior to trying to run wine, you’re on path.
The poorer your filter pad alignment, the poorer job of saturating, the looser the tightening job, the less clear the wine, the more you use pads out of sequence, the longer the pads are pushed past full, and the more you miss the switchover from water to wine as you start filtering, the more wine you’ll lose.
If your wine isn’t clear, that’s not what filtering is for, that’s what clearing / fining / time is for. Even with clear wine, make sure to start with the coarse filters and work your way down to the desired level of filtration. All that said, done properly, you will lose wine through the filtering process, period. The more you run, the lower the loss as a percentage, but if you’re doing little batches, it’ll eat ‘em up. Wine filtering is a big, but not contentious debate, more of a personal preference. If you need to do it, then do it. If not, let your inner procrastinator take over the winemaking, let it sit.