Pool rules for baby 💦

When can you put your baby in the pool? Ive heard some ppl say right away, others not til 6 months cuz they cant wear sunscreen or something? It was 115 here in California yesterday and I was planning on putting baby in pool as soon as we are able. I have the highest baby spf, full coverage bathing suit/hat but just cant find small enough swim diapers anywhere. Just curious what you mamas are doing and where to find those swim diapers!!