"Per-filters" for hot water heaters

Aug 19, 2010
Champlain/Hudson Valley
The plumber added a canister type chemical treatment product before our electric water heater.
While it appears to be a filter, it deposits a compound which keeps the water's minerals from precipitating out, so I understand.
These appliances are apparently more common (or required?) before tankless water heaters.
I read a lot of "reviews and comments" online but came out with no comparison.

It takes the 3M Aqua-Pure AP-431 canister. $36 each is the price.
Substitute (cheaper) replacement canisters bare names like Aquaquest, Waterdrop, Fetta Filter and Pure-Up.
These substitutes cost 1/2 down to 1/3 the price of the 3M Aqua-Pure.

My question is is anyone knows if the cheaper ones are good or not.
I know 3M is a good name and I don't want to be foolish with a purchase decision.
I'm not familiar with this specific filter but what I've found before is the cheaper ones work just fine but have significantly less of the active media inside.

Just for example we have high chlorine at my house so I use a whole house carbon filter. The pentek filter is about twice as much but last a bit more than a year. The off brand filters only seem to last about 3-6 months max. Even just weighing them out of the box the pentek is much heavier.

Same with the fridge filters. Cheap ones work fine but last less time. Those are so easy to change and so much cheaper I do use the off brands. Though with the whole house filter I don't worry about them these days.