R/O water smells skunky

[mike31154]

If you like spending money on replacing DI resin often, then go ahead & plumb your system to your ATO. I think it's been fairly well documented that short runs of an RO system with high input TDS is going to burn through DI media in a hurry since the RO membrane rarely gets a chance to stabilize at a low TDS output.

So yes, disconnect the system from the auto top off & only run it when there's an opportunity to produce at least 10 gallons or more in a single session. Another good idea is to produce at least 5 gallons of RO water only and only after you've done that, start sending the output through your DI stage. You'll need a T-fitting & a shut off valve to divert the RO water before the DI stage. Find something to do with the RO only production water, like making tea or coffee, or beer & bubbly drinking water. This way, the RO TDS has a chance to get to the lowest possible level before feeding the DI stage and your DI media will last longer.

[Reef Pilot]

Originally Posted by mike31154

If you like spending money on replacing DI resin often, then go ahead & plumb your system to your ATO. I think it's been fairly well documented that short runs of an RO system with high input TDS is going to burn through DI media in a hurry since the RO membrane rarely gets a chance to stabilize at a low TDS output.

I've heard that, too, but not so sure if that is true. I say that because I run an RO/DI system, and haven't changed out my DI media in over 2 years, and it is still good. Not only do I feed my RO/DI directly to my sump with my own DIY ATO dual float fail/safe system, but I also have 2 pressure storage tanks before the DI (but after the RO) in my system. So I always have about 10g or so of ready RO water, which quickly filters through the DI on demand. We use the RO side for house water in the kitchen too, and those storage tanks always ensure a ready supply for that, too.

My RO membrane is also more than 4 years old, and still working good. I have dual TDS gauges, one after RO (but before DI) and the other measure after RO/DI. However, I have a flush bypass valve (and DI bypass, too), and whenever my TDS from the RO gets over about 2 or 3, I do a flush (about every couple months). After DI, the water tds is still always 0.