Best litter for second-hand self-cleaning box

Nice find picking up a second-hand self-cleaning unit — they're genuinely useful once you get the right litter in them. The key thing to know is that most automatic rakes rely on tight, firm clumps to work properly: if the litter crumbles or clumps loosely, you end up with a jammy mess and a very unimpressed tabby. Before I point you to the best option, can you tell me which unit you've got? The brand or model makes a real difference — some (like Litter-Robot) need a specific clumping type, while others are more forgiving.

The PetSafe Simply Clean uses a slow continuous rotation rather than a rake, which actually gives you a bit more flexibility than some other units — good news for you. It still needs a clumping litter to work, but it's less fussy about granule size than a Litter-Robot. The main thing to watch with a 6-year-old cat who's used to standard clay is texture: you want something that feels similar enough that she doesn't stage a protest. Has she ever had any litter box avoidance issues, or has she always been pretty reliable about using it?

Perfect — reliable cat, budget to protect, and a unit that isn't overly picky. My clear recommendation is Arm & Hammer Clump & Seal Multi-Cat litter. It forms very hard, tight clumps that the PetSafe Simply Clean handles cleanly without jamming, the granule texture is close enough to standard clay that most cats accept it without fuss, and it has genuine odour control baked in rather than just masking scent. It's widely available on Amazon UK in 14lb and 28lb bags, and the larger bag works out well under £20. The 'Multi-Cat' formula just means stronger clumping — it's perfectly fine for a single cat and actually gives you better performance in an automatic unit. Avoid anything labelled 'lightweight' or 'crystals' for this machine; both tend to cause problems with the rotation mechanism.

Gradual is always safer with an older cat, especially when you're also introducing a new box at the same time — that's two changes at once from her perspective. Start with about 75% her old litter and 25% Arm & Hammer Clump & Seal, and shift the ratio over 10–14 days. If she's using the box without hesitation after a week, you can speed that up. One practical tip: run the PetSafe Simply Clean with the lid off for the first few days if that's an option on your model — the motor noise can spook cats initially, and letting her investigate it while it's moving helps her get comfortable before she has to actually use it.

Good call — the larger bag is much better value and you'll get through it quickly enough that freshness isn't an issue. Hope she takes to the new setup without too much drama. If the mechanism ever starts struggling, the first thing to check is clump depth: fill to about 3–4 inches, no deeper, or the rotation can labour. Good luck with it.