This tool tells you about how long your water filter cartridge will last before you need to swap it out. Water filters get used up over time. This gives you a number so you can plan ahead instead of finding out the hard way when your espresso machine or steam oven starts having problems.
Restaurant owners, foodservice operators, equipment installers, RV owners, or anyone who has a water filter cartridge protecting equipment and wants to know when to change it.
- Your cartridge's grain capacity (or pick it from the dropdown if it's an Aquamor cartridge)
- Something that tells you about your water, even a cheap TDS meter is fine to start
Pick from the Aquamor catalog and we'll auto-fill the capacity below. Or skip and enter your capacity manually.
Auto-filled when you select from the catalog above. Override anytime, or enter manually if your cartridge isn't listed.
Select the measurement type that matches your test report or meter.
If entered, the calculator will also show approximately how many days until replacement.
| Measurement | What it actually measures | How good is it for this cartridge? |
|---|---|---|
| Total Hardness (gpg or ppm) | The calcium and magnesium dissolved in your water, the minerals that form scale and that this cartridge is designed to remove. | HIGH, tells the cartridge exactly what it's up against. |
| Alkalinity (ppm) | The carbonate part of your water's hardness. Think of it as the fraction of hardness that "activates" the cartridge. (Alkalinity is the carbonate and bicarbonate dissolved in water.) | HIGH, often even more precise than Total Hardness, because this cartridge only treats the hardness tied to alkalinity. |
| TDS (ppm) | Total Dissolved Solids, every single thing dissolved in your water, lumped together: hardness minerals, salt, chloride, metals, and more. It doesn't separate the stuff this cartridge removes from the stuff it can't touch. | MEDIUM, a useful ballpark, but can be misleading. See below. |
| EC (µS/cm) | Electrical conductivity: how well your water carries electricity. The meter doesn't measure hardness at all; it takes a conductivity reading and then guesses at TDS, which then gets converted to a hardness estimate. That's two guesses in a row. | LOW, the roughest option. Still better than nothing, but treat the result as a wide range, not a precise number. |
This cartridge works by swapping out calcium and magnesium, the minerals tied to alkalinity (the carbonate fraction of hardness), for something harmless. That's all it removes. So when you tell it exactly how much calcium and magnesium you have, it can give you a tight estimate of how long it will last.
TDS and EC count everything dissolved in the water, including things the cartridge never touches: salt, chloride, trace metals, and more. If your number is driven by those other things rather than by hardness, the estimate will be off.
Think of TDS like weighing a grocery bag without knowing what's inside. Sometimes the weight is mostly the stuff your cartridge handles, calcium and magnesium. Sometimes it's mostly salt or minerals the cartridge can't touch. The number is real. It just doesn't always mean what you'd hope it means. Hardness and alkalinity tests open the bag and weigh only what matters.
Softened water: A water softener trades calcium and magnesium for sodium. Your TDS barely changes, but the cartridge load drops to near zero. A TDS-based estimate will make it look like the cartridge is working hard when it's barely doing anything.
Coastal or high-sodium water: Some groundwater and city supplies naturally carry a lot of sodium. Same problem: sodium pushes TDS up, but the cartridge doesn't see it at all.
Reverse osmosis (RO) blends: RO strips almost everything out, then some systems blend a little untreated water back in. The mix can be unusual, and TDS won't tell you which part is hardness.
EC meters specifically: Two meters measuring the same glass of water can show different numbers if they were calibrated differently. The default conversion factor in this tool (0.50) works for most meters. If yours was calibrated with a different solution, adjust the EC factor field above to 0.67, or better yet, switch to a TDS or hardness reading if you can get one.
1 gpg = 17.1 ppm (this conversion is exact). TDS to hardness uses a ratio of roughly 1:40, an average that holds for typical groundwater but breaks down in the situations described above. EC to TDS uses the factor you see in the form (default 0.50). These are real numbers; the uncertainty is in whether your water fits the average.
When in doubt, ask your distributor for a hardness test strip. It takes 30 seconds and gives you a HIGH-confidence number.
An Aquamor DI system uses mixed-bed ion exchange, which removes essentially all dissolved ions (sodium, chloride, sulfate, silica, and the rest), not just the hardness a scale cartridge targets. That makes DI right for spot-free rinse, process, and high-purity water.
Because a DI system removes everything dissolved, its service life is driven by your total TDS or conductivity, not hardness. When you pick a DI model from the dropdown, this calculator switches to DI mode automatically: it treats your TDS reading as the full ionic load and converts it directly (1 grain per gallon = 17.1 ppm), with no hardness discount. Entering hardness alone for a DI system would badly overstate its life. The math is simply rated capacity in ppm-gallons divided by your feed TDS in ppm, for example, a DI21 rated 7,900 ppm-gallons at 200 ppm feed TDS gives roughly 40 gallons of deionized output. DI cartridges are replaced (not regenerated) once exhausted.
Quick capacity estimator. Actual life depends on hardness, alkalinity, flow rate, and water chemistry. Designed for equipment protection (70 percent-reduction endpoint), not drinking-water polishing.