Rodi storage using float valve to keep storage tank full

[Jej34]

A bit confused, a lot of folks run their rodi unit for a few minutes before making a batch of RO to flush out any contaminates due to the system sitting idle for a few days.

When you build a storage unit that automatically tops off your storage tank, you would lose that "best practices" step.

Am I missing something?

 

[ngvu1]

Good question.

The booster pump from aquatic life will flush the membrane for a few seconds every time it is turned. It shuts off automatically when the intake water is cut off. I don't know if this booster pump will flush the membrane again when water intake is back on.....after turning off for sometime

 

[cromag27 Verified Sponsor]

You aren't missing anything. that's why I never recommend such setups. you will experience tds creep and foul your filters/membrane prematurely.

Even worse is when people have their rodi set up to directly top off their tanks.

A bit confused, a lot of folks run their rodi unit for a few minutes before making a batch of RO to flush out any contaminates due to the system sitting idle for a few days.

When you build a storage unit that automatically tops off your storage tank, you would lose that "best practices" step.

Am I missing something?

 

[redfishbluefish]

I'd never do this. What you do is eat through you DI resin quickly because of the constant ON/OFF, and each time, the breakthrough TDS has to be removed by your DI resin. Not recommended.

 

[Waterjockey]

My Rodi storage tank is 30 gallons with a float valve and a manual isolating valve in between. I fill it once every few months. I run the rodi to drain for a few minutes then open the manual fill valve. The automatic float valves lets me wander off and forget about it. Next day or two, I'll shut the manual valve again. No loss of "best practices"

 

[AZDesertRat]

If you use a float valve which I discourage, fill the vessel then manually shut off the RO/DI so it does not come on again until the level drops at least 5-10 gallons or more when you manually turn it back on again. This minimizes the effects of TDS creep or you can even open the DI bypass valve when you turn it back on to eliminate TDS creep water altogether.
I use and recommend a solenoid valve and float switches which you set a good distance apart so the volume drops the 5-10 or more gallons before it restarts automatically. I have used this configuration for 9 years now. DI lasts a long long time that way.

 

[SoftballReefer]

I ise float falve system but it doesnt constatly run its more there to keep water from spilling out if i leave or forget to turn off.

 

[Tastee]

I run a float valve on my system connected to a pressure sensitive solenoid. This shuts off the inlet supply once the RODI reservoir fills. I run this manually every 2 weeks or so (turn on the inlet tap, let it fill, solenoid shuts it off, I then turn off the inlet tap). Mine is an Aquatic Life system using their float valve kit.

I do fill my ATO from my RODI reservoir but in 2 stages - once a day a pump fills my gravity fed ATO from the RODI. This is a Neptune ATK driven by Apex filling a stock RSR ATO.

I can run this automated if I want (e.g. if we go away for an extended period) but in that case the RODI runs every day. I would get a little TDS creep from this. In my case my incoming water is fairly good (70-90 TDS, no Chloramines) so that’s not a big issue. Yes I will burn a little more DI resin, but not a lot.

If I was installing a system to run consistently more frequently and/or had worse source water I would ensure I had a flush cycle after the RO membrane before the DI reservoir to stop TDS creep exhausting my DI quickly.

 

[KStatefan]

I use float switches to control my RODI tank. System does not come on until the lower level switch is activated. When that comes on the first minute of RO water is sent down the drain then water is sent to the DI filters.