Air Water and Ice RO/DI unit

[Chyendra]

I'm looking to buy this unit used from someone in my local club and I'm wondering if anyone else out there has used this RO/DI unit before, and you got good water results.

 

http://www.airwaterice.com/product/1COMPAC...eeper_RODI.html

 

Air Water and Ice

Compact 75GPD Reefkeeper

4 stage + DI

 

Thanks!

[Rockfish]

i have it and i love it.......0TDS always!!! buy it!!!

[AZDesertRat]

It really depends on what condition the filters are in and how much they want. New that unit is $139. If they can assure you the unit has been in use right up until you buy it and when the filters were last replaced and what the TDS is running it might be worth it. If it has been sitting and the membrane and DI resin have dried out then you need to look at the cost of a replacement membrane and DI at a minimum and its probably wise to replace the prefilter and carbon at the same time. Now it starts adding up.

The key is RO membranes need to stay wetted once they are in use, if they are allowed to dry out they go bad.

[Chyendra]

Thanks for that advice, I didn't know that about RO filters. So, do I need to make sure that I'm running the filter a lot if it's hooked up? or can it be hooked up to the water source but not be used for a few weeks.

 

The guy said that the membranes are brand new, and he would put them in for me. he's asking $75.

[AZDesertRat]

You need to use an RO at least every 10-14 days or so. If its going to be down much longer than that the manufacturers recommend you remove the membrane, place it in a ziploc bag with some water and store it in the back of the refrigerator. If you use it portable, by that I mean hook it up to a faucet when making water then store it out of the way until next time, make sure you keep water in the housings so the membrane and DI resins stay wet, don't drain it out.

You say membranes but I imagine what he is referring to are replacement filters such as the prefilter, carbon and possibly a DI cartridge. Membranes are not usually kept around since they are somewhat expensive and usually last 3 years or so. Hopefully you are getting a TDS meter with it, you will need one to monitor the RO and DI condition and when to replace both the membrane and the DI resin. A TDS meter does not tell you when to replace the prefilter or carbon so most suggest following the 6 month rule, replace them every 6 months regardless of usage and always disinfect the system when replacing filters. If he replaces the filters make sure he follows disinfection procedures as recommended by AWI and others.

 

See if he will give you TDS readings before you but it. You want to know his tap water TDS, RO only TDS before DI and the final RO/DI TDS. The tap water reading and RO only readings are important as they tell you the condition of the RO membrane, the most expensive part of the system, $35 to $50 or more. The RO only TDS should be 96-98% less than the tap water TDS or it needs a new membrane soon. The final RO/DI TDS tells you the condition of the DI resin cartridge and should always be 0 TDS or very close to it, if it gets to 2-3 change the DI resin.

[Chyendra]

So I got this unit and so far I love it!

 

Tap water: 370 TDS

RO: 0-1 TDS (This was the very 1st gallon of output, so it might actually be 0)

RO/DI: 0 TDS

 

This is a great improvement from the grocery store water I was buying at 8-27 TDS.

 

So far, I highly recommend.

[AZDesertRat]

Excellent! RO only will not produce 0 TDS since it is not an absolute barrier but it should get you in the 98% removal range. What are you testing with and how are you testing? If its a handheld is it temperature compensated and calibrated. If its an inline there is not much you can do but they are close enough.

[Chyendra]

I have a handheld TDS meter that I bought used from another reefer. It doesn't have any thing on it to calibrate it with, but it's from Hanna Instruments. There are two valves on the RO/DI unit and I can't quite figue out how they are suposed to work. One is labeled RO only, and when I open it, nothing comes out. and the other is labeled DI bypass... Which in my mind means the same thing as RO only?? either way I turn the valves, the water coming out the other end is 0 TDS, so I'm happy. Maybe I'll see a difference down the road.

[Weetabix7]

I have one, I like it.

[Rockfish]

I have the 75 GPD unit with the D/I bypass as well and i love the thing......i'm 6 months in to using it and still 0 TDS even the micron has turned a lovely shade of brown