RO/DI Unit Storage

Shep · Jun 15, 2015

So I only use my unit maybe once a week but during the down time the water just sits in unit, is this a problem? Should I take the filter housings off and dump them out or what? Thanks!

143MPCo · Jun 15, 2015

tagging along, always wondered myself on this one... thx for posting @Shep

redfishbluefish · Jun 15, 2015

Tagging as well.....it's what I've been doing since 2007, still with the same membrane. So it works for me. I run my unit to waste for about the first five minutes of startup, bypassing the DI, until TDS is about 2.

143MPCo · Jun 15, 2015

redfishbluefish said:
Tagging as well.....it's what I've been doing since 2007, still with the same membrane. So it works for me. I run my unit to waste for about the first five minutes of startup, bypassing the DI, until TDS is about 2.

Whats your TDS sit at (tap-water wise)?

Gopi · Jun 15, 2015

This is what I do too...With the heat of summer upon us, I should probably at least bring it in from the garage when not in use.

redfishbluefish · Jun 15, 2015

143MPCo said:
Whats your TDS sit at (tap-water wise)?

240 - 250

143MPCo · Jun 15, 2015

Not that this is a complaint because its not but, I sit at 25-35 and wonder if that's a fluke... sorry not trying to hijack this thread.

Shep · Jun 15, 2015

redfishbluefish said:
Tagging as well.....it's what I've been doing since 2007, still with the same membrane. So it works for me. I run my unit to waste for about the first five minutes of startup, bypassing the DI, until TDS is about 2.

What have you been doing? Lol do you let it sit or dump it out?

Gopi · Jun 15, 2015

143MPCo said:
Not that this is a complaint because its not but, I sit at 25-35 and wonder if that's a fluke... sorry not trying to hijack this thread.

I'm curious too. My input tds was 0.07 yesterday so I was wondering where others were too.

redfishbluefish · Jun 15, 2015

Shep said:
What have you been doing? Lol do you let it sit or dump it out?

Oh, I'm sorry....like the OP....let it sit....sometimes, if I've made a whole bunch of water, up to three to four weeks. Again, at any start-up, I flush the membrane and then run the first five minutes or so to waste, until the TDS drops. You don't want to open those canisters up (or the membrane) and let them sit dry.

AZDesertRat · Jun 15, 2015

Always store the system with water in the housings so the membrane and DI resin stay wetted. Once they are wet they must stay that way or they are ruined.
Try to use the system at least every 10-14 days and store it in a climate controlled place out of direct lighting and protected so nothing gets broken off.
When you hook it back up it is wise to open the DI bypass valve if you have one or disconnect the line from the RO to the DI or remove the DI cartridge and flsh the TDS creep out. Flush kits do not do this so don't waste your money on them.

Gopi, there are no decimals in the TDS reading, it is 7 TDS. What appears to be a decimal is really a power on indicator. There are only a small handfull of handheld meters capable of reading down to a single decimal point such as the HM Digital COM-100 which reads in tenths

cdness · Jun 15, 2015

Store wet, but don't store wet in a garage that reaches sub-zero temps in the winter. RODI canisters like to explode

OOPS

AZDesertRat · Jun 15, 2015

Thats why I said "climate controlled" such as a interior closet, under the sink or in a cabinet somewhere. Never ever expose a RO or RO/DI to temperature extremes, either hot or cold. Hot is 113 degrees and can damage the membranes glues and TFC fabric and freezing goes unsaid.

redfishbluefish · Jun 15, 2015

AZDesertRat said:
When you hook it back up it is wise to open the DI bypass valve if you have one or disconnect the line from the RO to the DI or remove the DI cartridge and flsh the TDS creep out. Flush kits do not do this so don't waste your money on them.

I agree that a flush kit does not "flush" what you termed creep (or breakthrough), considering this TDS is now on the "good side" of the membrane. But I always assumed it flushed the "bad side" of the membrane. So are you saying that the flush kit I have on my unit is a waste. I typically open this valve up on startup and let it "flush" for about a minute or so, and then close. I continue bypassing my DI for approximately five minutes to allow the creep to get washed away. Appreciate your wisdom.

dbl · Jun 15, 2015

redfishbluefish said:
I agree that a flush kit does not "flush" what you termed creep (or breakthrough), considering this TDS is now on the "good side" of the membrane. But I always assumed it flushed the "bad side" of the membrane. So are you saying that the flush kit I have on my unit is a waste. I typically open this valve up on startup and let it "flush" for about a minute or so, and then close. I continue bypassing my DI for approximately five minutes to allow the creep to get washed away. Appreciate your wisdom.

This is how I do it, now I'm wondering along with you if I've been doing it incorrectly! Will follow along in suspense.

cdness · Jun 16, 2015

AZDesertRat said:
Thats why I said "climate controlled" such as a interior closet, under the sink or in a cabinet somewhere. Never ever expose a RO or RO/DI to temperature extremes, either hot or cold. Hot is 113 degrees and can damage the membranes glues and TFC fabric and freezing goes unsaid.

Yeah I forgot it was there and it sure made a mess.

Gopi · Jun 16, 2015

AZDesertRat said:
Gopi, there are no decimals in the TDS reading, it is 7 TDS. What appears to be a decimal is really a power on indicator. There are only a small handfull of handheld meters capable of reading down to a single decimal point such as the HM Digital COM-100 which reads in tenths

Thanks for clearing that up for me! I thought the reading was awfully low...

runzwithscissors · Jun 16, 2015

I also use mine just once a week. I let it run into the sink for 15-20 minutes or so just to clear out the water that has been sitting. Back flush after running.

AZDesertRat · Jun 16, 2015

For a flush kit to provide any benefit at all it should be used on shut down, not start up, each and every time the system is used. The theory, which has never been documented that I am aware of, is that it increases the velocity in and arpund the RO membrane scouring the surface and carrying the built up solids away to the drain. Sounds good in theory but the problem is you do not have sufficient pressure, volume or velocity to actually do this with a little 1/4" tube. In large commercial, industrial and municipal systems they do this but also have the ability to inject bursts of air and to inject chemical cleaning agents to aid the clean in place. Very different. When the membrane is sitting dormant the TDS on the waste side is osmosing to the treated side so on start up it is actually lower than tap since much of it is on the other side of the membrane now. Flusing with higher TDS tap water isn't going to help anything.

The other issue is unless this is done each and every time you shut your system off, from day one, you are allowing solids to build up on the membrane and no amount of flusing in the world will ever get rid of them.
Save your money, keep your waste ratio at the manufacturers recommended amount and install the DI bypass valve on the treated side to extend your DI life. This is shown to save you money.