Question: How do I remove the A-cartridge from the AQ-4000 if it is stuck?
Answer: Because it is very important that the A-cartridge not be bypassed by the untreated water, the AQ-4000 forces a strong seal on the A-cartridge. If you are having difficulties removing your A-cartridge, all you need to do is fold up a towel on your kitchen counter, and with the A-cap removed, give the filter a couple of turns (with your fingers), then a light tap or two on the counter, and the cartridge should jump right out. If this does not work for you, please call Sun Water Systems tech support at 1 (877) FDA-PURE.

Question: If I'm the only one using the filter, can I wait 12 months to change the cartridges?
Answer: The AQ-4000 is certified to treat 500 gallons, which means that we had to prove the performance through 1000 gallons to give you a built in safety window. Even a family of 6 is unlikely to use a full 1000 gallons in a six month period. However, carbon is the building block of life, and will allow bacteria to colonize on its surface as soon as it gets wet. Unlike the AQ-4100 and EQ-300 which use KDF-55 (55% copper, 45% zinc), the AQ-4000 does not contain anything to inhibit bacteria growth. We use B.A.S.F. ATS Sorbent Medium ion exchanger in place of KDF-55 in drinking water filters because it has better 2+ ion affinity at low flow rates and low temperatures. Some companies use silver to prevent bacteria build-up, but recent studies have shown that silver has similar health effects to lead. Silver collects in the left testicle or the left ovary and can cause hypertension, brain damage, and other negative health effects. Companies that use silver in their cartridges must register their products with the FDA as a pesticide. Because there is nothing toxic in our cartridges to prevent bacteria growth, the AQ-4000 will reach detectable levels of heterotrophic bacteria after 7-8 months, and dangerous levels after 12-14 months. To prevent bacteria build-up, the AQ-4000's cartridges should be changed every 6 months, regardless of use. The KDF-55 used in the AQ-4100 and the EQ-300 prevents them from growing bacteria, so a single person using the AQ-4100 Pure Shower System can go a full year between cartridge replacements, and the Rhino EQ-300 can be used until your water bill shows that you've used over 300,000 gallons.

Under-Sink Installation Video (.wmv)