These cistern blocks are a bargain - 30 pence for a pack of two. This compares to the branded version "Bloo blocks" which are up to £1.85 for two. I bought a pack of the Tesco value ones last time I went shopping, thinking that it's a pleasant way to keep the toilet fresh without having to use bleach every day. In the name of Dooyoo research I actually made a note in my diary of the date I put the block in the cistern to see how long it would last. Sadly, I needn't have bothered because about three days later the water in the toilet was running clear again and the block had run out.

The blocks are easy to use, you simply drop them into the cistern at the top of your toilet, the opposite side to the flush handle, wait five minutes and then flush the toilet to get the water running blue. After that, you just leave it to do its work and every time you flush the toilet the water goes blue and soapy and although it doesn't really smell of anything, it just makes you feel confident that your toilet is fresh and clean. The idea is that the block cleans the toilet each time it is flushed without the need to use bleach, so it's kept clean all the time. This is especially nice when you have visitors because if they pop to the toilet you're not sitting there thinking "I hope the toilet looks clean"!

The staying power of these bloo blocks is not great. It lasted about three days before the water ran clear, which was disappointing because I thought the idea was that it would last a while without me having to do anything. I may as well just keep using bleach every day. Although the branded products are more expensive, they do claim to last for up to four weeks, so I think next time I would pay a bit more because for a product that works it probably works out cheaper in the long run.