I have 6 litter trays and rarely notice any smell from them, have asked others too and they can't smell them either. I use Cat's Best OKO, scoop thoroughly daily and scoop poo when I see it. I keep a Litter Locker in the house which makes it easy and keeps all smells locked in. Once a week they're emptied, washed with hot soapy water then I use Clean & Safe coconut discinfectant that's safe for litter trays.