If I already have a spiro at boilor ( can hardly service its that tight) . This magna is mainly to dose and fit Magnaclense is it OK on flow ?For the filter to be most effective, as suggested, you need to have it after the primary return from the HW cylinder where it meets the main return and then before the boiler.
That may require the return to the boiler, in the cupboard possibly, to be rerouted to allow space for the filter to be fitted.
Or would it just be batter dosing chemical from radiator and connecting magnaclense to radiator. ( although not as easy as to filter )

