Thanks mike and Darren I totaly agree with what you are saying but I accept compared to some of the very knowledgeable people on hear I know very little and am very willing to adapt and learn/ use new things but the results we have been getting for years with hypo are instant and very good that’s what my customers want : I have used algo clear and yes it’s good stuff but slow working and the dirt is still on the walls , personally I prefer using it as an after treatment as I have found this works well , but again like you say there are health and safety issues with bio products I was talking to a guy the other day who used to use a lot of bio stuff and he has stoped using it due to a constant sore throat and severe headache s since he’s stoped using it the symptoms have gone away he swore it was the bio causing this , and yes he was using the approved ppe according to the data sheets provided by the manufactures , thanks for your comments it’s greatly appreciated