RODI question

neil82

Sting ray
M.A.S.C Club Member
#1
My RODI system sat dormant for about 3 months. There was water sitting in the canisters, but it was not hooked up to the main water line. What steps should I take to bring the system back online? The color changing DI resin indicates there should still be some life left. One other question, is the system supposed to remain under pressure when not in use? I shut mine off from the input so there is no water pressure going to it when not in use. Is that okay? Thanks in advance.
 

halmus

Registered Users
M.A.S.C Club Member
ex-officio
#2
Following along to see other opinions.

Do you have an in-line TDS meter? If you turn the system on and TDS is still acceptable, seems like it should be fine.

I use a small valve and shut off the supply when not in use. So, there is no pressure on my system when not active. Any pressure just bleeds off although it probably maintains a little water in the system since the input isn’t entirely disconnected.
 

neil82

Sting ray
M.A.S.C Club Member
#3
Following along to see other opinions.

Do you have an in-line TDS meter? If you turn the system on and TDS is still acceptable, seems like it should be fine.

I use a small valve and shut off the supply when not in use. So, there is no pressure on my system when not active. Any pressure just bleeds off although it probably maintains a little water in the system since the input isn’t entirely disconnected.
There is a tds meter. I don't trust it since it often reads zero on the 'in' setting. The system is at least a few years old. Another potential issue is water pressure. The gauge is reading 40 psi. At the old house it was about 60. Might need to look at adding booster pump. I'll probably try replacing the filter media beforehand because I have read that clogged filters can drop pressure.
 

scmountain

Administrator
Staff member
M.A.S.C Club Member
M.A.S.C. B.O.D.
B.O.D. Member-at-Large
#4
agree on the TDS meter not being a great indicator for system "health"
pressure should gradually fade away once the source is disconnected so no concern there.
3 months isn't a terrible length of time, but 3 approaches you could take...
Most expensive: replace all filters and media, clean all housings. The best peace of mind and no doubts about your water
Semi-expensive: replace sediment and carbon block, clean those housings. In theory, your RO permeate should be relatively clean so anything downstream of the membrane should be fine.
Least expensive: rinse everything out (minus the DI resin) and believe in your TDS readings

If you really want to nerd out...

Assessment of the extent of bacterial growth in reverse osmosis system for improving drinking water quality.
https://www.ncbi.nlm.nih.gov/pubmed/20512722

Great chart and the Scale at the bottom...
TYPICAL REJECTION CHARACTERISTICS OF R.O. MEMBRANES Elements and the Percent R.O. Membranes will remove
https://www.espwaterproducts.com/ro-contaminant-rejection-table/
 

neil82

Sting ray
M.A.S.C Club Member
#5
agree on the TDS meter not being a great indicator for system "health"
pressure should gradually fade away once the source is disconnected so no concern there.
3 months isn't a terrible length of time, but 3 approaches you could take...
Most expensive: replace all filters and media, clean all housings. The best peace of mind and no doubts about your water
Semi-expensive: replace sediment and carbon block, clean those housings. In theory, your RO permeate should be relatively clean so anything downstream of the membrane should be fine.
Least expensive: rinse everything out (minus the DI resin) and believe in your TDS readings

If you really want to nerd out...

Assessment of the extent of bacterial growth in reverse osmosis system for improving drinking water quality.
https://www.ncbi.nlm.nih.gov/pubmed/20512722

Great chart and the Scale at the bottom...
TYPICAL REJECTION CHARACTERISTICS OF R.O. MEMBRANES Elements and the Percent R.O. Membranes will remove
https://www.espwaterproducts.com/ro-contaminant-rejection-table/
Hey thanks for the reply. I did end up replacing the sediment, carbon, and DI media and cleaning out the housings. I left the RO membrane for now because it wasn't very old (in use for about a year) but I have a replacement on standby. The water pressure is still 40 and water production is slow. Considering a booster pump. Water prices are high here in Erie. Anyone good with interpreting water quality report? Just curious how good or bad the source water is. Here is the link to water quality report: https://www.erieco.gov/Archive.aspx?AMID=82
 

scmountain

Administrator
Staff member
M.A.S.C Club Member
M.A.S.C. B.O.D.
B.O.D. Member-at-Large
#6
Hey thanks for the reply. I did end up replacing the sediment, carbon, and DI media and cleaning out the housings. I left the RO membrane for now because it wasn't very old (in use for about a year) but I have a replacement on standby. The water pressure is still 40 and water production is slow. Considering a booster pump. Water prices are high here in Erie. Anyone good with interpreting water quality report? Just curious how good or bad the source water is. Here is the link to water quality report: https://www.erieco.gov/Archive.aspx?AMID=82
40 psi is average residential pressure. IIRC it takes me about 15hours to fill 55g
Make sure you add a "waste water saver" it will increase your water production and is very cheap DIY (https://smile.amazon.com/gp/product/B07QTGYHB3/ref=ppx_yo_dt_b_asin_title_o02_s02?ie=UTF8&psc=1)
 
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