It just depends on the TDS out of your tap. Your pressure the unit will run at. Even the temperature will effect how long the filters will last. The DI resin I change every 3 months or when I see 5 TDS after making water. It's 35 bucks in bulk on Amazon and I can refill my cartridge 6 times. The Ro filter lasts me about 2 years. Carbon and sediment about 4-6 months. That's making 30-40 gallons of water weekly.
Which RODI system?
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I use Spectrapure and in SoCal we have about 400-500TDS out the tap so I replace my carbon and sediment filter every 6 months like clockwork. For how cheap they are it is great peace of mind.
if you are exhausting your DI resin that fast you may want to consider a better membrane or running more pressure. I make less water per week but I haven't had to touch my DI resin in nearly a year. Even with our bad socal water I get less than 10 TDS after the RO membrane and that is with 400-500 going in.
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Dominat0r
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Does it shorten the life of the filters/resin if you have it turned off? As in no water in the unit for a few weeks to a month? (unless there is a way to flush, which still leads me back to the original question.
Also, at what TDS rating does it become unsafe to use for reef?
Thanks for the info.
Also, at what TDS rating does it become unsafe to use for reef?
Thanks for the info.
Letting the membrane completely dry is not good for it, no. Flush kits seem to be a debated topic still in terms of efficacy, but you will want to use your system at least weekly and for more than a gallon at a time for it to stay in optimal condition. In terms of what TDS rating does it become unsafe? Anything above 0 after the DI resin is when either prefilters (sediment and carbon), DI resin, or the membrane, in that particular order, needs to be replaced. You can find out the rejection rate of your membrane by measuring TDS from your source water and TDS after the membrane but without any DI resin and take the output/input TDS values to calculate. A well functioning RO system should have 96%+ rejection rate, and DI resin should bring it down to 0. 50-60 PSI is considered the minimum for them to work right, and 75-95 psi considered ideal. Booster pumps can help with this if your source pressure is low.
