RO Top-Off for 300 Gal Tank?


New member
My 20-year-old UltraTec-USA four-stage RO unit (UT083?) is suddenly leaking (quite heavily - 5 gals/day) at the first stage. Replacing the O-rings had no effect and I can't begin to imagine what else the problem might be. The unit was originally installed by pros who've since gone out of business, so I'm on my own and sorta overwhelmed by the complexity of the thing. To complicate matters, there's a Flow-Pur 185 in the waste water line that may or may not have anything to do with the problem.

Is it worth troubleshooting or should I simply replace it? I'm sorta hoping the state-of-the-art has produced something more user-serviceable in 20 years. And, do I really need an 18 GPD water filter when my tank only loses a tiny fraction of that per day?

Come to think of it, this setup was originally designed to also serve a gravity-driven water-change sump that never happened. When things were fresh (and unstable), we were doing 40-gal water changes every week. I suppose this still might happen, since my back isn't getting any younger, but it's still well shy of 18 GPD, especially now that they aren't happening weekly.

Any advice is appreciated.


Well-known member
Give Russ a call at I have no doubt whatsoever that he can help you figure out what the problem is and then get you whatever it is you need to get it back up and running. He's bailed me out several times over the years.

Great guy, great customer service, great company.


Could have cracks in either the canister housing or head unit. Switch with adjacent housings to see if its the cause. Housings are standard sized thread and just have to match female or male threading and swop out. I find the clear ones (PE) fail before the opaque (HDPE) type.

If its the head, easy to replace with ones from HD/RONA/Lowe's/etc but can be a PITA with all the tight spatial tolerances and may have to reconfig with MIP-QC fittings.



New member
Thanks, guys!

Sorry for the slow reply - I thought I had subscription notifications turned on.

Yes, it's the clear housing that's failed. Great idea - I'll try swapping them.

Thanks again!