Think it depends on how confident you are in a child's ability to not poo in a pool. At first, I put one on ds just to be safe. He was 80% ok but still the odd accident. Now I know when he goes and he's fully in control I go without.
Dh always goes on about the amount of chlorine that kills all the germs. But it still makes me feel a bit queasy.
Can't see why if they're properly trained. (or do you mean you're in the process of potty training?). The swim nappy only holds solids anyway - so hasn't been containing wee the entire time you've been using it!
Once potty trained in the day time, should toddlers still wear swimming nappies? I can totally see the 'common courtesy to other pool users' argument but my book says they never go back into nappies except for naps and night time. Any opinions on what's best and what you've done very gratefully received. Thanks.