Rodi help

[Wagonpitt]

I want to set up a permanent rodi holding reservoir that will fill itself. wondering how people fight tds creep from ro membrane and di resin.

out of tap 500+ tds
when i start the rodi i flush ro membrane for couple min.
then i let water run through prefilters and membrane and down the drain untill 4-5 tds
then i finally let it run through di resin but even that water comes out 1-3tds for first couple min so i also let that go down the drain.
Once it hits 0 i hook it up to ro reservoir.

so im worried if its always running to fill reservoir. How do people flush the ro membrane and what about first few min of 1-5 tds from tds creep.

not sure if im explaining right.

End goal is
1. 40gal ro reservoir automatically filling 5gal reservoir under my tank for top off. will do this through solenoid and float switch
2. awc that gets water from 40gal ro reservoir.

 

[AJsReef]

T ball valve on the file line, with one end down the drain. When you go to make water set it to flow down the drain until your happy with TDS. Once your happy switch the flow to the display.

That said, TDS creep is much less of an issue if you’re only cycling it once every 40 gallons. The impact on your DI resin will be negligible. I’ve ran my reservoir on auto fill in 25 gallon intervals for many years without any noticeable change in DI usage. My incoming TDS is in the mid 300s.

Edit - just realize you want to auto fill and auto empty. If that’s the case do you have a controller? You’ll want high/low optical or float sensors. If not, Avast sells a product called a “barrel tender” that will automate without the need for a controller

 

[Wagonpitt]

hey thanks for the help. Yes i have the hydros i was planning on using solenoid and float switches. If the quad cable ever comes in stock.

my issue is that after di resin i get 1-3tds coming out for first minute or two. Then goes to 0. Not so much worried about di resin being exhausted. Just dont want that tds in ro reservoir.

Not sure how much impact .5gal of 3tds has on 40gal. Likely very little. Probably overthinking this.

if you could post a pic of your setup that would help me visualize it better.

 

[Wagonpitt]

Is it normal for tds to come out of di then drop to 0. Mostly i read about tds creep in ro membrane not so much di resin

 

[KStatefan]

I have a delay relay on the output of my High-Low tank controller. When the controller turns on the system the first few minutes of permeate is routed to the drain.

 

[AJsReef]

hey thanks for the help. Yes i have the hydros i was planning on using solenoid and float switches. If the quad cable ever comes in stock.

my issue is that after di resin i get 1-3tds coming out for first minute or two. Then goes to 0. Not so much worried about di resin being exhausted. Just dont want that tds in ro reservoir.

Not sure how much impact .5gal of 3tds has on 40gal. Likely very little. Probably overthinking this.

if you could post a pic of your setup that would help me visualize it better.

If you have TDS coming out of your DI I’d just add another DI canister assuming you only have a single one. Should be good after that

 

[DopamineKata]

Isn't that what an auto flush/flow kit is for?

 

[AJsReef]

Isn't that what an auto flush/flow kit is for?

They don't do a true autoflush at start up, its a periodic autoflush every 60 min

 

[vetteguy53081]

With high TDS, consider a whole house filter and even softener

 

[Woodyman]

A permeate flush setup would reduce the initial startup TDS creep.

 

[Snoopy 67]

For years I never worried about it, never realized it either.
Then I thought about it -- if you make a significant amount of water & say 40 tds for 10minutes into 30 or more gallons that takes 6 or more hours to make equates to what? Miniscule would be my answer.
However in the new place I do flush before & after a run.

 

[AJsReef]

For years I never worried about it, never realized it either.
Then I thought about it -- if you make a significant amount of water & say 40 tds for 10minutes into 30 or more gallons that takes 6 or more hours to make equates to what? Miniscule would be my answer.
However in the new place I do flush before & after a run.

If you're getting 40 TDS post DI stage you need additional DI stages. Regardless of TDI into your DI assuming your DI isn't spent you should be getting 0 out.

 

[DopamineKata]

They don't do a true autoflush at start up, its a periodic autoflush every 60 min

They do a flush every time it powers up. Which could be every time the float valve opens due to the pressure switch. That's pretty much the whole point.

 

[Snoopy 67]

Referencing TDS meters before & after the membrane on my post.

 

[AJsReef]

They do a flush every time it powers up. Which could be every time the float valve opens due to the pressure switch. That's pretty much the whole point.

Per BRS "The system will be flushed when the unit turns on for a few seconds, and then for 15 to 20 seconds per every hour of use"

A few seconds likely isn't sufficient to flush the membrane completely.

 

[Wagonpitt]

I have a delay relay on the output of my High-Low tank controller. When the controller turns on the system the first few minutes of permeate is routed to the drain.

Thats a good idea for my di outflow. How does the relay switch/change outflow from drain to your container ? A pic would realy help. I think of relay as on off like a car relay. But how would that relay change outflow instead of just turning a outflow on or off.

If you have TDS coming out of your DI I’d just add another DI canister assuming you only have a single one. Should be good after that

Thats great idea to get more use out of each di refill. But not sure how would solve tds creep in di resin. i guess tds would be trapped by first di canister then by time it comes out of second di canister it should be 0 from the start.

just not sure how/why the tds builds up in my first di canister to begin with. I understand it if it was old and exhausted.
maby there is a problem with my system. is it normal to have initial tds in di outflow. Like i said for first couple minutes ill get 1-3tds coming out of di resin then it goes to 0. Most “tds creep” i read about is concerning ro membrane. Havnt read about people having tds from di resin unless di resin is exhausted.

Isn't that what an auto flush/flow kit is for?

Didnt think about it but if i want it to be automatic i wont be there to turn the flusher on and off. Duhhh. So thanks for bringing to my attention. i will def need one of those to flush ro membrane. And could also be useful for letting some di outflow go to waste before going to reservoir.


i think ill add a second di canister i can atleast extend life of each canister, and maby will solve tds in initial outflow from first di canister. Also will need that auto flush kit for ro membrane flush.

 

[Wagonpitt]

With high TDS, consider a whole house filter and even softener

Whole house filter ? I have softener and will install rodi after softener. i have it hooked up under the sink for now so still after softener but i want to turn furnace room into kind of a fish room-ish. Softener is in furnace room. I planned on adding a T to output of softener and run rodi unit from there. Hopefully get more psi aswell.

They do a flush every time it powers up. Which could be every time the float valve opens due to the pressure switch. That's pretty much the whole point.

Per BRS "The system will be flushed when the unit turns on for a few seconds, and then for 15 to 20 seconds per every hour of use"

A few seconds likely isn't sufficient to flush the membrane completely.

interesting points Ill have to look more into. Currently tap is ~500 (softened water). i usualy flush around 5min Tds goes really high. Then starts dropping after 5 min flush its gets to <100. When i turn flush off and it actually goes through ro membrane i get output of 3-4 tds that then goes into di resin.

what alternatives are there to this flush kit? For people who dont use that but have automated rodi reservoirs. How do you guys flush your ro membranes. ?

 

[AJsReef]

Trying to understand - you’re saying your getting 1-3 TDS out of the membrane on starting filling? I wouldn’t even worry about that as “TDS creep” at all if you’re making 40 gallons at a time. Seriously, you will notice no difference in the depletion of your resin. You’d have to be cycling your RO on/off tens of time a day to even have a noticeable impact.

maby there is a problem with my system. is it normal to have initial tds in di outflow. Like i said for first couple minutes ill get 1-3tds coming out of di resin then it goes to 0. Most “tds creep” i read about is concerning ro membrane. Havnt read about people having tds from di resin unless di resin is exhausted.

 

[vetteguy53081]

Whole house filter ? I have softener and will install rodi after softener. i have it hooked up under the sink for now so still after softener but i want to turn furnace room into kind of a fish room-ish. Softener is in furnace room. I planned on adding a T to output of softener and run rodi unit from there. Hopefully get more psi aswell.




interesting points Ill have to look more into. Currently tap is ~500 (softened water). i usualy flush around 5min Tds goes really high. Then starts dropping after 5 min flush its gets to <100. When i turn flush off and it actually goes through ro membrane i get output of 3-4 tds that then goes into di resin.

what alternatives are there to this flush kit? For people who dont use that but have automated rodi reservoirs. How do you guys flush your ro membranes. ?

Not as bad as it sounds. I use a whole house filter which help tremendously

Dupont unit ( Under $30)

 

[Wagonpitt]

1-3 tds out of di resin for first minute or so.

So tap is ~500.
That goes through prefilters and ro membrane.
out of RO membrane i get 4-5tds.
That then goes into my di resin.
Out of di resin 1-3tds for first minute or so. Then it goes to 0.

for that first minute or so i let the rodi go down the drain. Then after that first minute tds goes to 0 and i put the rodi line into my reservoir

Realistically less then 0.5gal of that 1-3tds comes out. Id prefer if i can keep that very miniscule amount of tds out of ro reservoir.
But as im explaining this now i realize im probably over thinking this and 0.5gal of 3tds in 40gal barrel probably has next no impact.

in my head it was a bigger problem until you guys making me think it through