Have just purchased a shower thermostatic mixer from Screwfix.
Instructions mention the need for a scale inhibitor if temporary
hardness more than 200 ppm. Local water has hardness of nore than 400
ppm!

Triton scale inhibitor costs £50 + £25 for replacement cartridges. I
already have a magnetic device fitted (? Ecoflow). Ebay has two on
offer - a Calmag scale inhibitor that requires regular cartridge
replacement, and a Salamander Sesi electrolytic scale inhibitor.

My question is - do these things work? Are they worth fitting? Are
they a con?

All comments gratefully received.

Keith