RO/DI... Need advice

[Dj City]

I've had my tank up and running for about 3 years.
I've battered nitrates the entire time. No matter what, I can't get below 40ppm. All other parameters are great.

I've never used RO/DI and I'm beginning to think that's been my problem.

I can get a brand new BRS unit or I can get this used unit...
https://washingtondc.craigslist.org/nva/hsh/6081044806.html

I have a 110gal display with about 15 to 20 gal sump.

Please advise...

 

[red13]

Sorry got click happy

 

[red13]

And again.

 

[d2mini]

Personally, I'd go with a 5 stage instead of 4 stage, with flush valve to extend the length of the membrane, and a dual TDS meter that checks the input and output at the DI.

 

[nervousmonkey]

+1. D2 right on target. RODI units are one thing to spend the extra money on. You want 0 TDS water, and only way to know is by having a TDS meter built in. I would add to get one that comes with a pump to help get your pressure up if your RODI needs it. You can add a pump later, but it's really nice having a built in one that kicks on when it's needed. Either way, listen to R2's advice and get at least the flush capability as well as the dual TDS meter function. Make sure you have 0 TDS water.

 

[Dj City]

The guy selling it has the in-line tds meter and the flush valve kit.

This is a 4 stage ro/di unit.
I'm thinking for $60 (price I'm getting it for) I can't go wrong.

I can replace the carts with brs carts and I can upgrade the DI to 100gal per day from aquafx.

If I'm looking at this wrong please let me know where I'm going wrong (as long as it does not leak).

He has all the fittings.

 

[nervousmonkey]

sounds good, just make sure you factor in the cost of new cartridges and RO membrane into the total cost. It's not really just $60, but the rest sounds good.