I've just seen this for the first time now. I used the filter posted earlier in the thread for the first time over the weekend- the in laws bought one as the water marks on their black and dark blue cars were awful. To be honest I thought it was rubbish. The flow from the hose was greatly restricted and it took ages to rinse the car plus you have all the hassle of changing over the power hose to the filtered hose pipe water. I think I could have used a good drying towel in the same amount of time and get better results.