I need to descale my combi boiler as the throughput is now down to trickle. The only descaling pump I can find is the Kamco Eco-scale C10, which retails at around £300. Does anyone know of any other manufactures, which come in below this price or know of a DIY method to do the job. I guess if I use the proper equipment I can use a more corrosive agent, whereas if it's a DIY method then something like Fernox DS-3 would be more appropriate.