Neoterics Blaster 1000 Automatic Pool & Spa Cartridge Filter Cleaner

I was sceptical about this, especially for the high price. But it works very well. By blocking off some jets with the supplied "blockers" you can adapt it for different lengths of filters. Just leave it on for 10 mins and it does a great job. I'm in the UK and have normal water pressure - which is quite sufficient. Slow rotation and strong jets.