Rodi help

[Wildreefs]

Can someone please explain in layman’s terms how to tune or run a rodi with a valve that controls waste water

I’ve had this unit for 2 years and still can’t figure out the proper way to set it up. It’s the aqua fx, 100 gallon per day with 7 stages.

It has 1 sediment, 2 carbon, then into membrane, followed by a di and then I added on two extra di’s to have the different di resins (cation, etc) it has an aqua tech booster pump.


I have the booster pump turned all the way to the right, which i believe is high . The waste water valve (knob you turn that control the waste and subsequently the good water ) is mostly open, and my psi reads at 40. Right now I’m at about a 3 to 1 ration of bad to good water. Even with booster pump, I’m at 40’psi. To bring pressure up to 80, I close off waste valve, but then my ratio is closer to 1 to 1 .

Always thought with RO, you wanted 3 to 1 or 4 to 1
Ratio.

Please advise

 

[lapin]

To bring pressure up to 80, I close off waste valve, but then my ratio is closer to 1 to 1 .

Always thought with RO, you wanted 3 to 1 or 4 to 1
Ratio.

Don’t worry about the ratio. You want to keep the waste closed off. It is only used to flush the gunk off the outside of the ro membrane , once every so often. 80 psi is very good

 

[Wildreefs]

Don’t worry about the ratio. You want to keep the waste closed off. It is only used to flush the gunk off the outside of the ro membrane , once every so often. 80 psi is very good

So with the waste line closed, where does the rejection water go?

 

[UncommonSense]

Wait… this system runs a needle valve or gate valve on the waste line? Odd…

Why not just replace that novelty with a much more common metered orifice flow restrictor?

 

[Justdrew]

3-1 or 4-1 is the correct ratio for a single membrane unit. Do not close off the waste valve.

 

[Wildreefs]

Wait… this system runs a needle valve or gate valve on the waste line? Odd…

Why not just replace that novelty with a much more common metered orifice flow restrictor?

It’s a knon you turn, tighten it and less water goes thru waste, more to good (builds more pressure on membrane) turn to loose it and more water runs out to waste, less pressure in membrane.

 

[UncommonSense]

It’s a knon you turn, tighten it and less water goes thru waste, more to good (builds more pressure on membrane) turn to loose it and more water runs out to waste, less pressure in membrane.

Yes, so its a valve; likely needle type, possibly gate type…

I’ve never personally seen one of these used on a RO waste water line… the common solution is a flow restrictor, usually with a bypass valve for membrane flushing!

 

[Malum Argenteum]

That sounds odd. Have you contacted the company to see what they say about it?

 

[Wildreefs]

I did call, they called me back, little
To no instruction. Basically said people adjust then as they want to make the most water out of them. No mentioned ratio,

 

[Malum Argenteum]

little
To no instruction

That's lame.

@Buckeye Hydro , wanna make a new customer? Maybe you know what's up with this.

 

[Shirak]

3:1 or so for waste:RO is about right. 40psi sounds low. That sounds like normal water pressure. I would look into the booster pump. Turning the waste down further to boost pressure is bad for the membrane.

 

[Malum Argenteum]

I think I found the part:

AquaFX Adjustable Quick Connect Flow Restrictor

www.aquariumwaterfilters.com

That seems oddly complicated. Personally, I'd remove that and just get the appropriate flow restrictor and get on with life. Buckeye should be able to advise on proper sizing for your situation to get the pressure where it should be.

 

[Wildreefs]

3:1 or so for waste:RO is about right. 40psi sounds low. That sounds like normal water pressure. I would look into the booster pump. Turning the waste down further to boost pressure is bad for the membrane.

I think it’s 3 to 1 because I have the valve so open the water just shoots out the waste line and leaves little to get thru the membrane. Path of least resistance or something like that. Kinda like have no restrictor in there at all.


I guess my problem is with a manual restrictor in there you just set and defied, this one gives a lot of play

 

[UncommonSense]

I guess my problem is with a manual restrictor in there you just set and defied, this one gives a lot of play

Normally you sorta want to just set and forget once you find the correct product:waste ratio to reach Your RO membrane’s manufacturer specified rejection rate!

Conveniently, many these flow restrictors also just drop into the end of the waste tubing before reinstalling it into the RO membrane housing’s waste fitting! — that said, you just swap size if you ever change RO membrane spec!

Capillary Flow Restrictors

At Buckeye Hydro we specialize in providing the highest quality water filtration systems and accessories for every potential need.

www.buckeyehydro.com

 

[lapin]

I guess my problem is with a manual restrictor in there you just set and defied, this one gives a lot of play

One of these is a complete solution. Pick the one closest to you units gph

Reverse Osmosis Membrane Flush Valve

The Membrane Flush/Flow restrictor valve is an all in one flow restrictor equipped with a flush valve for easy worry free use. Keeping the flush and flow restrictor in a single package keeps fitting count down which means less chance for possible leaks or failures down the line. 550 mL/min for...

fresh.bulkreefsupply.com

 

[Buckeye Hydro]

Don't adjust your concentrate flow in an effort to achieve a better pressure.

MEASURE the ratio of concentrate to permeate. Can't be estimated accurately.

If you have a 100 gpd membrane, AND if you're at something near a 4:1, AND your booster pump is only putting out 40 psi... then something is wrong with the booster pump. Or maybe the placement of your pressure gauge is incorrect.

An adjustable flow restrictor (small needle valve) is not practical on these residential-scale rodi systems. We use them on commercial/higher volume units but not the small units people in this hobby typically use.

The devil is in the details here. Feel free to give us a call when you are in front of the system.

Russ
513-312-2343

 

[Wildreefs]

Don't adjust your concentrate flow in an effort to achieve a better pressure.

MEASURE the ratio of concentrate to permeate. Can't be estimated accurately.

If you have a 100 gpd membrane, AND if you're at something near a 4:1, AND your booster pump is only putting out 40 psi... then something is wrong with the booster pump. Or maybe the placement of your pressure gauge is incorrect.

An adjustable flow restrictor (small needle valve) is not practical on these residential-scale rodi systems. We use them on commercial/higher volume units but not the small units people in this hobby typically use.

The devil is in the details here. Feel free to give us a call when you are in front of the system.

Russ
513-312-2343

Didn’t read this until just now.

As of right now I am at approximately a 2:1 waste to good water ratio. (Used two Home Depot paint cups marked with ounces, ran waste line in one, clean in the other, started filling at same time, by the time the waste hits 20 ounces, the good was at 9.5).

The pressure gage read 60 with booster pump on with this ratio. If I made it more like a 1:1 ratio, then I could achieve 80
Psi, but it sounds like I shoud not do that and leave it at a 2:1 with 60 psi at the gauge.

If I opened up the waste water line to achieve a 4;1, I believe the pressure gage would go down in the 40’s. I am in NJ, temps have been in the 20s at night and 30s in the day

 

[Buckeye Hydro]

If you have hard water, a 2:1 ratio of concentrate to permeate is too tight and you will shorten the lifespan of your RO membrane.

How is it that your pump won't provide decent pressure? Something is wrong. Give us a call when you are in front of the system if you'd like.

Russ
513-312-2343