Rodi makes less than half of the advertised amount. Advice needed

[firebirdude]

I didn't read every single reply, so pardon.

But what's your question? You know why you're getting the poor output levels. You've got very low pressure. Additionally, the water temperature will affect output. There are switches for both the booster pump and to auto-shut off the RO system. Sounds like you've got no problems and all your needs have been met by the industry. lol

And as I saw mentioned, the 3:1 and 4:1 rejection ratios are a must. I could force mine to do 1:1 if I wanted. But then I'd have to replace my DI resin every other day....

 

[Buckeye Hydro]

Long story short, my water pressure is 40psi and that equals out to maybe 40 gpd.


They recommended a booster pump for 150$ but since I'm using food grade containers w a float valve, I have to manually turn the pump off when I make enough water . I know there are some pressure sensors that can be used but am not sure whether it would work for me.
As a side note , the rodi set up apparently does not have a auto shutoff valve so the water just keeps running and running into waste when The containers are filled

Your situation is easily addressed.
1. Booster pump will increase your pressure.
2. If you get a Booster Pump Kit, it will include a pressure switch, which will automatically shut the pump down when your reservoir is full.
3. It's a good thing that you don't have an ASOV. If you get a Booster Pump Kit with Shut Off Solenoid, not only will the system shut itself off, it will also stop the flow of water to the system when your reservoir is full.

Here's a graphic to depict how the various components go together:

Russ

 

[Buckeye Hydro]

Do you withdraw small amounts of water at a time from your reservoir? This might happen if the reservoir has no lid and evaporation slowly occurs, or if water in the reservoir is transferred by gravity flow or pump to make up for evaporation in your system (a.k.a. top off water). If so, your system, now including the pump etc, will short cycle - meaning it will kick on and off frequently. This should be avoided for a number of reasons. I can provide more info/details if you'd like.

Russ

 

[Buckeye Hydro]

How do you know how many gallons you should expect from your membrane if your pressure and water temperature don't perfectly match the membrane manufacturer's specs? Use our calculator.

Remember that the "90 gpd" membrane mentioned earlier is actually a 75 gpd membrane the vendor tells customers to run at 10 psi over the manufacturer's spec. That is, ANY Filmtec 75 gpd membrane can be called a 90 gpd membrane if you run it at a temperature and or pressure higher than the product specs. For example - look at the expected output from a 75 gpd membrane ran at 60 psi (10 psi over the spec) and 77F (factory spec).

Russ