RO/DI Questions

[KingRicky]

I have an Air, Water and Ice Compact III 75GPD with DI Bypass Assembly and TDS Meter that I bought used about a year ago. My questions have to do with the DI. As I said, I bought the unit used and can't remember how long it was used before I got it. I would guess that the unit is close to 2 years old.

1. Can the DI resin spoil or go bad enough to contaminate the water?
2. Can running used up resin hurt the tank?
3. How long does DI Resin last?

I tested all my water this morning with the following results.

Raw Water 99.4ppm
RO Out 00.0ppm
RO/DI 00.0ppm

Any comments would be appreciated.

 

[JR's Reef]

Ive always been told that once its used up will start releasing phosphates back into the water. It depends on your water I replace mine around every 6 months. I get my from bulkreefsupply and get the cartridge that can be refilled the DI refills are cheap like $10. I also replace my carbon block every 6 months

 

[Sharki]

What are you using to test your TDS? If the unit is 1-2 years old and you haven't had to change any of your filters or DI your source water must be awesome or you don't go through much.

1. Yes, it can definitely leach what it's taken out back into your water once the media has been exhausted but usually at much higher concentrations.
2. If you have an sps tank it won't be very happy. Some softies like crappy water.
3. Completely depends on how well your RO is working, what your source water starts out at, your pressure, and other stuff. Best thing to do is be sure to test very regularly.

 

[HighlandReef]

I would double check your Tds, your meter might need to be calibrated, I think I remember brs selling the fluid.
Your water being only 99 at the main is low compared to my water, might be normal
But it's probably would be good to double check just incase the meter is off

 

[AZDesertRat]

1. Yes
2. yes
3. It all depends on how much water you make, what your RO only TDS is and if your water contains dissolved CO2.

I am only aware of one hobbyist grade TDS meter that reads in tenths and that is the HM Digital COM-100 so you may waht to check your TDS numbers again.
How and where are you testing and with what? It is entirely possible your tap TDS is only 99 but even then I would expect to see a RO only TDS in the 2-3 or higher range with a used membrane.

As long as DI resins stay wetted and used on a frequent basis its possible to get a year or more out of them but thats not common. New resin usually has a 6 month shelf life even when shipped in a vacuum sealed mylar bag and stored properly, after that it tarts to lose its electrical properties as in anion and cation charges.

If your TDS meter is a handheld model try testing various waters such as bottled distilled, water from the LFS and maybe bottled spring water which should register pretty high due to the mineral content. You my a need to buy a calibration solution and calibrate the meter. Hs it always been rinsed in RO/DI afte reach use and stored with the cap in place? TDS probes can get dirty and go bad if not cleaned after each use.

Hopefully you are right and all is well!

 

[KingRicky]

I tested my water again this morning.
Raw Water 081ppm
RO 002ppm
RO/DI 000ppm

I make roughly 45 to 50 gallons of RO/DI and 10 gallons of RO Drinking water every 2 weeks. 5 gallons a week for top off and 35 gallon water changes every other week.

The water here in Birmingham is really good and clean.

I have noticed an outbreak of algae in the last couple of weeks. All my parameters test out.

I reckon it's to order a replacement DI. Better safe than sorry.