RODI Phosphate Overload

MelindaP

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I would appreciate any inisght or guidance about this issue; I've been in the hobby for ~8 months, having down freshwater for a while before finally giving in. When I started out, I immedaitely went to making my own RODI, but I have been struggling as of late.

Issue: My BRS RODI system is seeming to struggle to filter out phosphates, with the Hanna reading continuously showing >2.5ppm both from the product water and at the post-RO, pre-DI stage. I have installed a booster pump (AquaTec) and have it working at about 73 PSI, but I cannot get it any higher because the ratio of waste to product water is low (~2.3:1, rather than 3:1). No amount of fiddling with it has worked, even adding in a bypass loop on the waste line to help alleviate pressure so I don't have to sacrifice ratio or PSI. I really need help!

The System: I have a 4 stage BRS RODI with a water save upgrade (two RO membranes plumbed in series), and an additional DI resin. As mentioned above, my waste line is Teed into a main waste line and a bypass loop back to the booster pump, which is plumbed between the carbon block and RO membranes. My TDS is reading 6ppm at the pre RO, post carbon stage, and 0 at the post RO, pre DI stage. I just replaced all media ~10 days ago (new RO membranes, sediment, carbon, and DI's. I use a combination of BRS and SpectraPure media, and I'm using the MaxCap high rejection DI resins from SpectraPure.

Source water is very hard and very high in phosphate and Copper. I have gotten the Cu under control, as well as everything else (parameter wise). But P is the bane of my existence and I am going crazy trying to figure it out!
 

Fish Fan

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Welcome to Reef2Reef!

Sorry you didn’t get a reply here, I’m not sure how to help you, but I’ll bump this so hopefully others will see it.

Good luck!
 

BryanM

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I use a combination of BRS and SpectraPure media, and I'm using the MaxCap high rejection DI resins from SpectraPure.
This is what I was going to suggest.... I'd probably start conversations with BRS and SpetraPure to see if there's another solution.
 

Reeferbadness

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How are you testing for Phospate? Are you sure it also works on fresh water?
 

DanyL

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I believe the Hanna checker expects the sample to be saltwater at 35 ppt, and thus gives an inaccurate result.
 

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