Will these filters fit my current system?
If your system uses standard 10-inch by 2.5-inch cartridges — which covers most iSpring, APEC, Express Water and similar under-sink systems — yes. Measure your cartridge: 10 inches long, 2.5 inches wide. If it matches, ours drop right in. The check takes ten seconds with a tape measure, and it works stage by stage: sediment, carbon block, and membrane housings all follow the same standard sizes, so a match on one stage means the format is standard throughout. If your cartridge is a different size, or your system uses sealed proprietary pods or inline cartridges, our filters will not fit — the standard is generous, but it is still a standard. When in doubt, measure before you order; length and width are the only two numbers that matter. No tools, no disassembly.
How does the subscription work?
Every 6 months we ship a box of 5 filters (3 PP sediment + 2 CTO carbon block) with free shipping anywhere in the US. You are charged $29 per delivery — $58 a year for ten filters. The box covers the two stages you replace most often: sediment every 3–6 months and carbon block every 6–12 months, so a delivery lines up with a real filter change instead of a warehouse shelf. The RO membrane is replaced separately every 2–3 years. There is no commitment behind the schedule: cancel anytime from your email receipt — no phone calls, no retention scripts, no cancellation fee. Prefer no schedule at all? The same box is $15 plus shipping, bought once. A TDS meter tells you when a stage is genuinely spent, so the calendar never forces an early swap.
How often should I replace each filter?
Rule of thumb: sediment (PP) every 3–6 months, carbon block (CTO) every 6–12 months, RO membrane every 2–3 years. A TDS meter is the honest signal — when your filtered water's TDS climbs noticeably above its baseline, something is spent. The order matters as much as the dates: the sediment stage catches sand, rust, and silt before they scar the carbon block, and the carbon block removes chlorine before it can damage the membrane, so skipping a cheap pre-filter change is how an expensive membrane dies early. Change the pre-filters first, retest, and only replace the membrane if rejection stays low. On clean municipal water, stages often run to the long end of their ranges; the meter, not the calendar, decides. Our replacement-schedule guide gives the replace signal for each stage in full.
Is the DIY RO system hard to install?
Most people finish in about 30 minutes with basic tools. Everything uses standard push-fit connections — push the tube in until it seats, tug to confirm, done. The kit arrives assembled on its open metal frame, with the PP sediment, CTO carbon block, and RO membrane already fitted, so installation is placement and plumbing connections, not construction: feed adapter on the cold-water line, faucet in a spare sink hole, drain saddle on the drain pipe, then the tubes. Our step-by-step installation guide walks through each of the nine connections, including the first flush and the leak check — dry every joint, run the system for 10 minutes, and inspect with a dry finger. No plumber, no proprietary tools. If you can use a wrench, you can do this. The printed guide is in the box.
Am I locked into buying your filters?
No. Everything we sell uses the universal 10-inch standard. Buy our filters, buy someone else's, mix and match — your system doesn't care, and neither do we. There is no RFID chip or authentication handshake in the housings, no proprietary cartridge shape, and no subscription you cannot cancel — cancel anytime from your email receipt, no phone calls required. The standard is the contract: any 10-inch by 2.5-inch sediment, carbon block, or membrane cartridge from any supplier drops into the same housings. We would rather win your next order on price — $29 every 6 months for five filters, free US shipping — than on a lock you cannot open. If our price stops being the honest one, switching suppliers changes nothing about your system. That is the design working as intended.