I've tried everything, from expensive Catsan clumping, to Asda value cat litter and simply emptying the entire tray daily. Nothing has worked and they've all smelt terrible within 3 days or changing the tray, despite me cleaning out the obvious bits every day. I saw this n my local independent pet shop and it was more expensive than the others, but I thought, "Worth a go."
It certainly was. My initial thought as I poured it into the tray was that the litter tray smelt more like a rabbit hutch than a litter tray, with a fresh woody smell. This was Sunday. We're now on Wednesday and it still smells like that! Not a single unpleasant odour to me found. It clumps beautifully for easy removal of wee, and the entire tray still smells fresh and clean.
Due to the set up of my house I have to have the tray in the kitchen, so it was vital I found one that didn't smell at all, and I finally have. This will be the litter we use from now on. I genuinely don't think there is better.
I haven't tried flushing it- I bin it, so can't comment on that, but as for doing its job, it's excellent.