There is no best powder, it's user subjective. I currently use a lot of Pureclean from Prochem and get on very well with it. You can vary dilutions which is really handy. I used Alltec's Ultimate for years with no problems. Double clean and Powerburst (Prochem) are great on pubs etc. A lot may say powders are bad for your pump, if you use it in your tank, but i've always diluted well in hot water and had pumps last over 3 years. Crystal Green is good but I kept getting blocked jets.