iSpring FA15B Inline Remineralization Filter
Add minerals and a healthy pH back to RO water
Prices checked Jun 2026. Marketplace prices change often — verify the latest price before buying.
Our Review
Reverse osmosis strips the minerals that give water its taste along with the contaminants. The iSpring FA15B is the simplest fix: an inline calcite cartridge that reintroduces calcium and magnesium on the way to your faucet, restoring a rounder taste and a healthier, less acidic pH.
It uses standard 1/4" quick-connect fittings, so it drops into nearly any under-sink RO system in a few minutes. For the price, it's the single best upgrade most RO owners can make.
Pros
- Cheap upgrade with a big taste payoff
- Universal quick-connect fittings
- Raises pH of acidic RO water
Cons
- Adds one more cartridge to track
- Slightly slows flow
The HU Recommendation
If you drink RO water daily and find it flat or slightly sour, add this. It's the cheapest meaningful taste-and-pH improvement in the category.
Prices checked Jun 2026. Marketplace prices change often — verify the latest price before buying.
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