RODI experts: Booster pump install on Dual purpose RODI system

[cgripp256]

So, I have an Express Water 50 GPD RO system installed under my kitchen sink.

When I began my saltwater journey with a 32 gallon Biocube I realized I could probably just add a DI cartridge to my existing system and have a dual purpose unit. I don't make RODI water for the aquarium automatically. I manually direct water through the DI and into 5 gallon jugs a few times a week and this works fine for me as I usually store them and make 30 gallons of saltwater at a time.

However, I recently added a 3 probe TDS meter and pressure gauge and realized that 1) my incoming pressure is around 50-55 psi and my TDS is 450 (incoming) 30 (post RO) and 2 (post DI). I am pretty sure my DI was 0 initially and I have only made about 50 gallons of RODI water.

I have the DI cartridge connected to the yellow line to the pressurized reservoir tank with a ball valve on the DI side to turn it on and off. When this valve is closed to the DI cartridge the RO water is stored into the tank and when needed it feeds into a carbon filter and then an Alk filter and out a drinking water tap at the sink. When it is open it pushes water from the tank initially, out the DI and then once the tank is depleted, from the RO membrane directly to the DI (Noticeable flow decrease)

Im not sure if Im getting any backflow from the carbon and alk at the end of the chain or bypass to the tank though.

I am looking at adding the aquatic life RO buddy booster pump to my system to improve the incoming pressure and hopefully increase efficiency. All the diagrams I have seen show it used for a single purpose RODI system.

Are there any gotchas to installing this with my setup? For instance, should I install any check valves anywhere? And could I just swap to a higher production rated RO membrane (100gpd to match the max of the pump unit). And would this speed my production when I do go to make DI water after the initial tank water empties.

Thanks!

 

[JoshH]

Honestly, purchasing a better membrane would get you further along than a booster pump. Your current membrane is only rejecting 93ish % and more pressure might help a touch, but nowhere near as good as a high quality membrane will.

 

[KStatefan]

You do want a check valve

 

[cgripp256]

You do want a check valve

Thanks! Do you concur that a better membrane would be a wiser choice than a booster? And if so any recommendations?

The above diagram is exactly my current setup minus the check valves. And given that I currently see 2 TDS after DI should I change the resin as well? It is color changing and shows no change yet.

 

[outhouse]

Do you concur that a better membrane would be a wiser choice than a booster? And if so any recommendations?

No if you have a 75g they tend to do the best job over a 100 membrane. As far as a booster pump, yes you should use one, I had similar pressure and have been over a decade with teh 8800 unit. get that exact one and you will thank me later. another trick you can try is different restriction amounts, I like to tune my system. The other reply correct you want multiple check valves.

 

[cgripp256]

No if you have a 75g they tend to do the best job over a 100 membrane. As far as a booster pump, yes you should use one, I had similar pressure and have been over a decade with teh 8800 unit. get that exact one and you will thank me later. another trick you can try is different restriction amounts, I like to tune my system. The other reply correct you want multiple check valves.

I have a 50 gpd.

 

[KStatefan]

Thanks! Do you concur that a better membrane would be a wiser choice than a booster? And if so any recommendations?

The above diagram is exactly my current setup minus the check valves. And given that I currently see 2 TDS after DI should I change the resin as well? It is color changing and shows no change yet.

I would start with a membrane. Your is not rejecting enough as @JoshH said. With the changes Dupont has been making in their membranes I think the Filmtec TW30-1812-50HR membrane is currently the best one. This membrane is speced at 99% stabalized salt rejection at 50 psi and 77° F. You wont get all the way to 99% with has high as your source TDS is but if you got to 97% it would double your resin life. If you want more a booster pump would increase production rate and rejection rate. I have been running this membrane since Aug of last year. I have been recording data each month after running the system for 30 minutes see chart below. After I have a year of data I plan on purchasing a new SpectraPure SpectraSelect Plus membrane and do the same test for a year.

 

[cgripp256]

I would start with a membrane. Your is not rejecting enough as @JoshH said. With the changes Dupont has been making in their membranes I think the Filmtec TW30-1812-50HR membrane is currently the best one. This membrane is speced at 99% stabalized salt rejection at 50 psi and 77° F. You wont get all the way to 99% with has high as your source TDS is but if you got to 97% it would double your resin life. If you want more a booster pump would increase production rate and rejection rate. I have been running this membrane since Aug of last year. I have been recording data each month after running the system for 30 minutes see chart below. After I have a year of data I plan on purchasing a new SpectraPure SpectraSelect Plus membrane and do the same test for a year.

Wow. I take it you’re in the business :) I appreciate the guidance and advice and will source that membrane today.

Is there any downside to adding a booster? I don’t mind the minor investment if it helps even a little.

 

[cgripp256]

Also, I’m at 3 months of use and I know that the manufacturer recommends a 6 month or 1 year replacement cycle depending on which filter in the system.

Do you have a better way of determining when to replace the pre and post filters? Time seems so “one size fits all” and not very accurate.

 

[YOYOYOReefer]

both good suggestions better membrand and the ro buddy is a good choice. I got one about a year ago its been super solid. Ive had home made booster/backflush setups and spent more to make similar.
ive left mine running for 3 days straight at the longest and it didnt break.

 

[KStatefan]

Wow. I take it you’re in the business :) I appreciate the guidance and advice and will source that membrane today.

Is there any downside to adding a booster? I don’t mind the minor investment if it helps even a little.

I am not in the business just have to make 0tds water at work and have done some research.

The only downside I see is cost. If I did not have high water pressure I would have a booster pump.

 

[redfishbluefish]

Agree with what @KStatefan posted above of the Buckeye Hydro diagram with a slight variation. I'm not a fan of check valves, so instead of the Tee right before the check valve, I'd use a Three way valve (BRS sells them):

With this valve, you're either making tank water or flipping the valve and using it for drinking.

Now I'd do one more thing to save your DI resin. On startup of any RO system you have breakthrough TDS that occurs when the membrane sits unused. It takes a couple minutes of running to clear this breakthrough TDS. So what I'd do is run your drinking water faucet for five minutes to clear the TDS and then flip the valve and start making tank water.

This breakthrough TDS is the reason you don't want to use that reserve tank water to make tank water. It has some level of TDS, and this TDS is what makes the water drinkable (tasteful).

Hope this helps.

And also agree with others....get a membrane that gives you 98%+ rejection.

 

[cgripp256]

I went to make water this morning after emptying about 2 liters of water for coffee making from the drinking tap and got 425 in, 15-20 post RO and 0 post DI. I did shut off the tank first which I normally don’t.

checked again after 45 minutes and 425/14/0

If my math is correct that means I’m getting 96.7% rejection, correct?

I’m guessing those initial results were due to having the tank opened?

also included a pic of my DI resin for reference.

 

[cgripp256]

Agree with what @KStatefan posted above of the Buckeye Hydro diagram with a slight variation. I'm not a fan of check valves, so instead of the Tee right before the check valve, I'd use a Three way valve (BRS sells them):

With this valve, you're either making tank water or flipping the valve and using it for drinking.

Now I'd do one more thing to save your DI resin. On startup of any RO system you have breakthrough TDS that occurs when the membrane sits unused. It takes a couple minutes of running to clear this breakthrough TDS. So what I'd do is run your drinking water faucet for five minutes to clear the TDS and then flip the valve and start making tank water.

This breakthrough TDS is the reason you don't want to use that reserve tank water to make tank water. It has some level of TDS, and this TDS is what makes the water drinkable (tasteful).

Hope this helps.

And also agree with others....get a membrane that gives you 98%+ rejection.

If I have a ball valve at the tank and just before my DI isn’t that equivalent to this valve? I know I have to turn two valves on and off but it would work the same, yes?

 

[cgripp256]

I just want to express my appreciation to all who respond and continue to do so. I know it probably gets old answering the same questions but I have really learned a lot from this thread and forum in general.

 

[MichaelReefer]

My house has very low water pressure, I was around 30-40 before...got the pump and now Im over 80. Makes a big different once my RODI production.

 

[redfishbluefish]

If I have a ball valve at the tank and just before my DI isn’t that equivalent to this valve? I know I have to turn two valves on and off but it would work the same, yes?

Yes that could work as well. But I'm an idiot and I'd forget and either have both valves open or both valves closed. The single three way can't be screwed up. :beaming-face-with-smiling-eyes:

 

[JOECANADIAN]

So, I have an Express Water 50 GPD RO system installed under my kitchen sink.

When I began my saltwater journey with a 32 gallon Biocube I realized I could probably just add a DI cartridge to my existing system and have a dual purpose unit. I don't make RODI water for the aquarium automatically. I manually direct water through the DI and into 5 gallon jugs a few times a week and this works fine for me as I usually store them and make 30 gallons of saltwater at a time.

However, I recently added a 3 probe TDS meter and pressure gauge and realized that 1) my incoming pressure is around 50-55 psi and my TDS is 450 (incoming) 30 (post RO) and 2 (post DI). I am pretty sure my DI was 0 initially and I have only made about 50 gallons of RODI water.

I have the DI cartridge connected to the yellow line to the pressurized reservoir tank with a ball valve on the DI side to turn it on and off. When this valve is closed to the DI cartridge the RO water is stored into the tank and when needed it feeds into a carbon filter and then an Alk filter and out a drinking water tap at the sink. When it is open it pushes water from the tank initially, out the DI and then once the tank is depleted, from the RO membrane directly to the DI (Noticeable flow decrease)

Im not sure if Im getting any backflow from the carbon and alk at the end of the chain or bypass to the tank though.

I am looking at adding the aquatic life RO buddy booster pump to my system to improve the incoming pressure and hopefully increase efficiency. All the diagrams I have seen show it used for a single purpose RODI system.

Are there any gotchas to installing this with my setup? For instance, should I install any check valves anywhere? And could I just swap to a higher production rated RO membrane (100gpd to match the max of the pump unit). And would this speed my production when I do go to make DI water after the initial tank water empties.

Thanks!

I know this is 3 years after the last post, but thought I'd add my recent experience for others. I ran a 4 stage RO for many years, and this worked fine for dringking water and top off water. However as my hobby and the need for more filtration for housing Reef inverts etc. both increased, I had more need for larger quantaties and on demand of RO water. Being an electrician, I built a DIY system on a timer and a float valve on a 20 gallon "open" storage tank (besides the RO tank) for storing the top off water, that would run for about 1 or 2 minutes about 4-6 times a day. This was because the system would produce about 3 gallons from the tank storage then obvioulsy drastically drop in flow, then take about 15-20 minutes to re-fill / recharge. Therefore in the mean time, I found myself buying 5 gallon jugs of R.O. water from the dealer. about 6 to 8 at a time. Although not too expensive, this gets a bit tiresome when driving to get them, loading them, driving home and carrying 2 at a time from the garage and all the way downstairs to the basement, then for "convinience" lifting and pouring into the tanks (after trated). Although it was a very good workout, I hurt my back a few times as i'm not a young buck anymore although my mind thinks otherwise. Recently my R.O. system failed and wasn't worth buying multiple parts (if available) for a 20 year old system, which by the way, had a waste water ratio of about 4:1. So I recently purchased a new 6 stage RODI "rated" 200 Gallons Per Day, with a booster pump. I used my existing tank as I only just replaced it a year ago when the other tanks membrane failed. I now mounted the new system and tank in the basement, so as to not take up all the space under the sink in the kitchen where it was before, but also we do not need to tap on the sink as I have always ran the "drinking water" line through my fridge for cold water and ice making anyway. It works fine but i'm still not getting the desired pressure and what I feel is enough volume both at the tap on the fridge, and for filling in the storage tank and for "on demand" uses. I have been researching permeate pumps and with that, updating my knowledge on RODI systems etc. It seems like a permeate pump witll both make the system work more efficiently and most likley reduce the stress on the RO membrane as well as help the water quality that sits in the tank,especially if only dispensing the odd coffee cup of water etc. This is not a concern as we all drink a lot of RO water in the house as well as it produces a lot of Ice in my fridge, and again, I use it for all my water top off's as well as now water changes. Then simply add anything that's needed afterwards for my specific tanks. i.e. Marine Reef, Fresh Planted, etc. BTW, For the fridge drinking water, I tee'd off the line, after the 6 stages, one to the "fish tank usgage" and one through a re-mineralization filter, to put all the good minerals back into the drinking water for our health. I put flow checks in the lines to prevent any back flow etc. Back to the permeate pump. I will install one and will see if A: As it should, make the system more efficient, and B: See if I get a measurable increase in pressure/flow at my fridge tap. Now I totally understand there are factors at play here that effects that such as, Gravity...AKA head pressure from having to go from the basment to my fridge upstairs, and also additional filters including the re-mineralization filter, and the existing filter in the fridge. (Which BTW I haven't changed in quite a while as it has only ever had RO water fed through it). Regardless, I may change that as its been many years. The new system now has all 1/4 inch lines on it. But after that, including to the RO tank and upstairs etc, it switches to 3/8 which if anything should help. I was getting better flow with my old system and same tank when it was under the kitchen sink on the same floor same room obviously. So depending what results I get with adding the permeate pump, I may also add a larger tank on the system, as well as possibly a pump on the very out going line. That would make 3 pumps on the system itself. Seems like there should be a simpler solution? I will update this thread as I move forward. Hopefully this helps others as it is intended.