RODI

jtl · Oct 18, 2018

Crabs Mcjones said:
one pre-filter and one carbon block? my guess is the carbon block is getting used up quickly, chlorine will eat away at an ro membrane

That is pretty low chlorine from what I have read.

jtl · Oct 18, 2018

Crabs Mcjones said:
Another question, what restrictor valve do you have on the system, any way you can share a picture of the whole RO/Di unit for us?

Not sure what you mean.

Fin · Oct 18, 2018

Do you know if you have chloramines in your city water? If any chlorine gets by that block, it will damage your membrane. Our municipal water supply has chloramines, so I use this Spectrapure 1 micron ChlorPlus cartridge.

Crabs McJones · Oct 18, 2018

jtl said:
Not sure what you mean.

There should be a restrictor valve of some type on the waste water line on your ro membrane

jtl · Oct 18, 2018

Crabs Mcjones said:
There should be a restrictor valve of some type on the waste water line on your ro membrane

550

jtl · Oct 18, 2018

Fin said:
Do you know if you have chloramines in your city water? If any chlorine gets by that block, it will damage your membrane. Our municipal water supply has chloramines, so I use this Spectrapure 1 micron ChlorPlus cartridge.

No chloramines. Believe it or not our little town uses RO water and then adds chlorine back to kill the bacteria in the old pipes.

Buckeye Hydro · Oct 18, 2018

jtl said:
I have been fighting a problem with my RODI for a year. I burn through RO membranes way too fast and the reason is unknown. I am lucky to get 400 gallons out of a new one and as they go south my DI resin is trying to compensate. For example I just changed the DI and after making 50 gallons it is 1/3 used. My incoming water is 210 ppm and afte the RO is is still 39 so you can see the problem. Just for reference I have researched this, talked to experts and even replaced the part that hold the membrane thinking it may be cracked all to no avail but I am still looking for suggestions. I religiously back wash the membrane and do not run hot water through it. Maybe I am just going to have to live with replacing the membrane every 7 months.

Feel free to give us a call when you are in front of your system if you'd like help troubleshooting it. Also, you can send us one of your old/bad membranes and we can do some autopsy work on it for you.

Russ

Joe148 · Oct 18, 2018

Do you have very hard or very soft water?

JoshH · Oct 19, 2018

Can you take a picture of your system? And your membrane housing as it is right now?

Buckeye Hydro · Oct 19, 2018

Do you EVER get good performance from the membrane? In other words, what is the TDS of your RO water right after you put a new membrane in?

Buckeye Hydro · Oct 19, 2018

Please MEASURE your ratio of permeate to concentrate (RO water to waste water). Line up 8 identical glasses (solo beer cups work great). With your RO water tube in one hand and your waste water tube in the other, how many glasses do you fill with waste water in the time it takes to fill one glass with purified?

Buckeye Hydro · Oct 19, 2018

Stonekeg said:
@jtl It looks like your filter is awesome, and your temperature is great, too. That leaves the weakish 40 PSI as the culprit in my mind. My 2 cents? Look into a booster pump for your unit. It might save you money (in the long run) if you can't get that PSI up to at least 50ish.

He has 50 psi feedwater - this is not the source of membranes repeatedly going bad in 7 months.

Buckeye Hydro · Oct 19, 2018

Crabs Mcjones said:
one pre-filter and one carbon block? my guess is the carbon block is getting used up quickly, chlorine will eat away at an ro membrane

Although your 5 mic carbon block is not top of the line, it is ok. It has a Chlorine Capacity spec of 6,000 gallons. So I'd change it out when you reach about half that total (3,000 gallons). Remember that all your purified water and all your "waste water" goes through that carbon block.

Russ

jtl · Oct 19, 2018

Buckeye Hydro said:
Please MEASURE your ratio of permeate to concentrate (RO water to waste water). Line up 8 identical glasses (solo beer cups work great). With your RO water tube in one hand and your waste water tube in the other, how many glasses do you fill with waste water in the time it takes to fill one glass with purified?

Hi Russ, You tried to help me several months ago and we never did figure out the problem. The ratio right now is horrible one glass of RO to 2 of waste water. I wish there was a simple solution but it doesn't appear to be that easy. Thank you.

jtl · Oct 19, 2018

Buckeye Hydro said:
Although your 5 mic carbon block is not top of the line, it is ok. It has a Chlorine Capacity spec of 6,000 gallons. So I'd change it out when you reach about half that total (3,000 gallons). Remember that all your purified water and all your "waste water" goes through that carbon block.

Russ

I don't think mine is set up that way. tap water>pre-filter>carbon>RO>DI. The waste line goes from the RO housing to a Y with a flow restrictor on one leg and the shut off for back washing on the other leg then to the drain. Is this right?

Buckeye Hydro · Oct 19, 2018

jtl said:
Hi Russ, You tried to help me several months ago and we never did figure out the problem. The ratio right now is horrible one glass of RO to 2 of waste water. I wish there was a simple solution but it doesn't appear to be that easy. Thank you.

You'll want to change your flow restrictor to improve that ratio. Good news is that flow restrictors are only $4.

jtl · Oct 19, 2018

Buckeye Hydro said:
You'll want to change your flow restrictor to improve that ratio. Good news is that flow restrictors are only $4.

Mine is 550, what size do I need?

Buckeye Hydro · Oct 19, 2018

jtl said:
I don't think mine is set up that way. tap water>pre-filter>carbon>RO>DI. The waste line goes from the RO housing to a Y with a flow restrictor on one leg and the shut off for back washing on the other leg then to the drain. Is this right?

Well... nothing in your description of the plumbing of your waste line affects the order of water flow through your system.

Buckeye Hydro · Oct 19, 2018

jtl said:
Mine is 550, what size do I need?

If the 550 isn't allowing enough waste, then you'll want to jump up to the restrictor for a 75 gpd membrane: https://www.buckeyehydro.com/capillary-flow-restrictors/

BTW, Because you have conditions that are close to factory spec (77F and 50 psi), I'd expect a 550 flow restrictor - intended for use with a 50 gpd membrane - to not give you enough waste water.

Russ

Forsaken77 · Oct 20, 2018

Crabs Mcjones said:
one pre-filter and one carbon block? my guess is the carbon block is getting used up quickly, chlorine will eat away at an ro membrane

This is my thought as well. BRS sells test strips that you can test either the waste or product water and if you get any reading, you need a new carbon block. These are just for chlorine. They have different ones for chloramine.

I would also suggest the 1 micron sediment and 1 micron carbon block. I've linked to the ones I use.

More gets through the 5 micron. I usually run a 1 micron and ran out and used a 5 for both and the tds going into the membrane is higher by almost 10.

The 50 psi going into a 75gpd shouldn't be an issue.

When you get a new membrane, you don't bypass the prefilters to rinse it, right? Because like Crab said, chlorine will destroy a membrane.