Anyone`s input would be awesome

I haven't checked my RODI phos. The TDS is always 0. What is yours?

 

Also some people say that the vials of the Hanna P checker can get stained and that you should swap them out every once in a while, but I've never had a problem as long as I empty them and rinse in hot water right away after the test is complete.

 

Also, why would you put a DI Resin before the RO membrane? That's going to burn out in no time. Then after that, why more carbon and sediment?

Your cartridges should go in order of micron, largest to smallest. usually all you really need is sediment, carbon 1, carbon 2, then right into RO membrane, after that, just DI. This is what I run, with 2 DI sections (standard canisters with inserts, not horizontal ones that sometimes come with cheaper DI units)

If you are really producing water at the 150 GPD rate, then this could be part of the issue I suppose - not enough contact time.

My membrane is a 150 GPD but my water pressure is relatively low, so I never get 150 GPD, more like 40, so my rejection rate is huge, I bet I put 5 gallons down the drain for every gallon of RODI I make. So I am putting that water very slowly through 2 canisters of DI resin (BRS color changing) and after probably 400 gallons since I added the 2nd one (and refilled the first) the first DI canister is just starting to show signs of changing color over, the second one is still solid blue.

I also made a DIY flush valve for my reject water off my membrane, a couple T's and a valve and wen you first fire up the production you open the valve to bypass the flow restrictor to flush it for 30 seconds, this gets all your built-up TDS out of the RO membrane houusing (dirty side) from it sitting there not running. Then let your RO production water run down the drain until the TDS stabilizes (preferrably really low, like 10 or less) and then engage the DI. Your RO output will be like 200 TDS (from the CLEAN side!) for the first half gallon or so until the RO housing is flushed out completely. If you don't do this, you'll burn out your DI resin that much faster.

DI resin is oppotunistic, so it will grab on to ions that have a stronger bond. When part of your resin is used up, or if your resin is packed too tight, along with other factors, possibly flow being one, you can get channeling which means you will have a low-resistance pathway and your RO water is not getting enough contact time in your DI. This can mean that when this part of the DI is saturated, then it will release ions with a weaker bond in preference for those with a stronger bond. Someone may correct me if I am wrong, but I believe that Phosphate is one of the weaker ions, thus it will be released more easily in such a situation.

I have a Hanna combo TDS/mS/pH meter and all calibration liquid, I use it all the time (indispensable), I could try to stop by sometime, I work near MHM, when are you around? I have an uber-busy week...might just have to loan it to you

 

Have you checked phosphates from the water strait out of the filters? Never touching any other container? What about just straight from the tap?

I've never checked phosphates from my RO/DI water, but after mixing up my saltwater for 24hrs it tests 0 for phosphates.

 

Was going to drop off meter today but was a long day...

 

Wow. Something is really wrong with your DI if you're getting that much out of your production water.