RO/DI system upgrade

[RTFinerfilters]

Oh okay! I obviously hadn't paid attention to the rest of that pdf as we only stock the EC-103-100 and EC-802-(50/75) presently. That's not to say we won't stock others in the future though!
Absolutely worth you doing your due diligence before committing to any further investment!
90ppm max is very soft, we're based in Southport, UK, and are used to TDS levels of around 250.

Do you know that your water board uses chloramine as a disinfectant to warrant the Chlorplus cartridges?
These 'Matrikx' cartridges may be worth considering as a cheaper alternative to the ChlorPlus for chloramine and/or heavy metal removal.
Matrikx Chloramine Removal Filters

Re. flow restrictor size; it depends on what size membrane you're going to be using. Some others in this forum might have more experience with this than I but these are the general guidelines we suggest.
Finerfilters Large RO Membrane Upgrade Kit

• 300cc ml/min - for use with 50 - 75 GPD RO membranes.
• 450cc ml/min - for use with 75 GPD RO membranes.
• 500cc ml/min - for use with 75-100 GPD RO membranes.
• 600cc ml/min - for use with 100 - 150 GPD RO membranes.
• 800cc ml/min - for use with 150 - 200 GPD RO membranes.
• 1000cc ml/min - for use with 200+ GPD RO membranes.

And yes you can install RO membranes vertically but we'd recommend horizontally as it should hold a more consistent pressure this way.

 

[gcodrutv]

From what manged to find, ec-204 50-400GPD is the only pump that can handle low incoming water pressure.
All other pumps form E-chen require minimum 30psi incoming pressure.

Matrikx 1 micron has a very good price. Definitely is an alternative to Pentek.

If I upgrade to 2 150 GPD RO membranes in series, do I need a 800cc flow restriction ?
I'm planning to feed the waste output from the first membrane to input of the second and the waste from the second to have a flow restriction.