RO/DI Question.

I bought a slightly used typhoon RODI unit made by airwaterice.com. he says that the filters haven't been used much. A friend of mine is a plumber and hooked it up for me. Water coming in is reading 82 and going out at 49. Does this mean I need new filters and that I kinda got taken? If I need new filters is can I get away with changing the DI filter or should I change all?

Thanks

Jay

 

How long do you let it run?

Also if you only change out your DI it will use it up very fast.

John

 

You can call up Russ at Buckeye Field Supply, Ltd. and he'll take care of you and send you the right filters you need to get 0 TDS. I even bought the inline TDS meter.

 

only ran it for about an hour

 

Running for 1 hour should have helped. Sometimes when a filter is used and then sits for period of time it can harden the membrane. Sounds like you need new filters and that just sucks, but run for a bit longer to make sure.
One other question does it have a bypass? If it does make sure that is off. If it is on then your water is running past the RO filter and then just flying through your DI. That could also give you a bad reading.

?

 

If you need a new DI filter you might as well replace all 3 at the same time. They usually need replacing every 6 months or so. The RO membrane is upto 2 years. At least it is on my Spectrapure.

 

If you're getting 49 out from 82 starting that might mean all the filters are shot or your tester is inaccurate. Your RO membrane should remove at least 90% of the TDS in water and the DI should take out the rest. If the RO membrane is taking at most 30tds out it doesn't sound good to me.

That's the problem buying used RO units, even if you save money on the unit if you have to replace all the filters right away that probably is going to negate any savings.

 

Could be several things.

One, what is the pressure of the water going into the unit?

Where are the test probes taking the readings at? before pre-filters, after? before the ro membrane, after? before the di resin, after?

It doesn't necessarily mean every filter is bad. Your DI might just be exhausted, or the pre-filters be spent, or just the ro membrane. In order to know which it is, its best to have several meters positioned on the unit, before and after each set of filters/membranes.