RODI system questions

[SaltWaterTank_Noob]

I'm not sure I understand what no waste means. Where does the waste water route? People seem to be saying it routes back to the supply. Is that correct?

Thats where I'm getting lost as well hahaha. I didn't know there was waste water, thought there was only clean RODI water coming out.

 

[SaltWaterTank_Noob]

From their website the waste water is plumbed to the hot water side.

An engineer designed the Tacoma Narrows bridge that only lasted a few months.

Wait wait wait, so then that means all the bad unfiltered water will just come out of my hot water when I use it??? So should I be letting the hot water run for a while before using it after installing this system?

 

[SaltWaterTank_Noob]

I have this setup from BRS:

BRS 4 stage Plus: $249

4 Stage Value Plus 75GPD RO/DI System

BRS 4 Stage Systems are perfect for reefers who have water treated with chlorine or relatively clean well water. The 4 stage systems are self-contained on a single bracket making them ideal for tight spaces or where a non-permanent connection may be required. Installing a RO/DI system only takes...

www.bulkreefsupply.com

This kit has everything you need including a TDS meter and a flush valve.

Replacement filters: $28.99
average time to replace them is around 6 months. or until your TDS meter is > than 1.

4 Stage RO/DI Replacement Filter Kit

Works with all BRS 4 Stage RO/DI Systems This kit is designed to treat all primary water sources that are treated with chlorine and wells with low amounts of contaminants. This kit will work with all BRS 4 Stage RO/DI Systems and most other RO/DI units on the market today that use industry...

www.bulkreefsupply.com

Membrane filter: $42
average time to replace them is once a year.

75 GPD Reverse Osmosis Membrane - Dow Filmtec

Why does BRS recommend this? DuPont is a leader when it comes to water treatment and filtration. Their 75 GPD membrane has a 99% rejection ratio, and most other membranes cannot make that same claim. Along with meeting NSF/ANSI standards the 75 GPD DuPont (formerly Dow Chemical) membrane is...

www.bulkreefsupply.com

Float Valve: $18.49

Reverse Osmosis Float Valve

Why does BRS recommend this? Float valves are simple to install and can save a lot of water from ending up on the floor. They can be installed in containers as small 1 gallon pails, sumps, and 200 plus gallon commercial storage containers to shut off the flow of water. Even if you do not have a...

www.bulkreefsupply.com

This goes onto the RO container, itll close the valve when the water is full in your container and stops the RO system. its a must have.

Hook it up via your washing machine cold water line. Install the float valve onto a water container of your choice.
This is all you need.

Yesss thank you, this is what I was thinking of getting after someone said it was only sale but it's out of stock now . I won't be doing the float valve because I'm only going to use it on and off when I need to do my water changes, I dont have enough room to keep a jug hooked up to the RODI or have an ATO system unfortunately

 

[SaltWaterTank_Noob]

No fresh water comes to the RO system some of it goes through the membrane part, the rest is diverted to the booster pump where it is forced back into the water heater. There is no waste line

I think i get it now, so without the booster then the "waste water" from the RODI system will go back into the hot water line BUT if you have the booster, then it allows the "waste water" to just bypass going into the hot water line and will go through the filter again so it cleans it and can be used?

 

[DrkNMighty]

Ohhhh, honestly, I didn't even know water went down the drain. I thought the RODI system just ran your normal water through the filters and spouts into my bucket that then goes into my tank and that's it. How does water go into the drain?

The RODI system does not produce water at a rate of 100%. The waste water rate differs by system and water pressure. It will produce RODI water at a lower rate than the amount of water consumed. The extra is the waste that goes back down the drain.

 

[SaltWaterTank_Noob]

The restrictor you are talking about does not reduce pressure by design anyway. It is called a backflow preventor it stops any containments from your home entering the town water supply. Why would you need a pressure gauge?

Ahhh interesting, I didn't know that. They were able to change the pressure on my house whenever they came with whatever they were messing with. I'm not sure, I thought i needed to know what pressure it was at to determine if I needed a booster pump or not but you're saying it's (booster pump) needed for different reasons.

 

[SaltWaterTank_Noob]

Funny does not mention how much water is wasted. If you look at a system in a store they have to tell you. Some waste 3 gallons and you only get 1 that is treated. Ask brs that

Do you know? I didn't even know these systems wasted water lol

 

[SaltWaterTank_Noob]

The RODI system does not produce water at a rate of 100%. The waste water rate differs by system and water pressure. It will produce RODI water at a lower rate than the amount of water consumed. The extra is the waste that goes back down the drain.

Wow, dang thats crazy, I did not know that. Do you know what is the % of waste water for the BRS 4 stage 75GPD system? So that's why the booster pump is important, cause it will allow for less % of waste water and more % of RODI filtered water?

 

[TastesLikeChicken]

I think the rejection rate is 3:1. That’s 3 gallons wasted for every 1 gallon of clean water made. You can improve it to 2:1 with some mods down the line.

There pump is also important so you don’t have to wait as long to get clean. The rate of water production is increased with the booster pump.

 

[Freenow54]

The booster pump comes with which system?

Maybe others as well I do not know. But Watts fo sure along with tank for water under a sink

Do you know? I didn't even know these systems wasted water lol

Just google any hardware store and search. That is how I found the one that I am talking about

 

[Freenow54]

Wow, dang thats crazy, I did not know that. Do you know what is the % of waste water for the BRS 4 stage 75GPD system? So that's why the booster pump is important, cause it will allow for less % of waste water and more % of RODI filtered water?

No just needed to force water back into water heater has to overcome your supply water pressure ie Town or well system. Don't know BRS system waste % they conveniently don't list it although its obviously made by some manufacturer

 

[SaltWaterTank_Noob]

I think the rejection rate is 3:1. That’s 3 gallons wasted for every 1 gallon of clean water made. You can improve it to 2:1 with some mods down the line.

There pump is also important so you don’t have to wait as long to get clean. The rate of water production is increased with the booster pump.

Is that normal, that seems like a lot haha?
What pump is important?
If the rate of water production is increased, does that mean the rate of waste is also increased? or does it improve with the booster so it could get to 2:1 or whatever.

 

[SaltWaterTank_Noob]

Maybe others as well I do not know. But Watts fo sure along with tank for water under a sink

Just google any hardware store and search. That is how I found the one that I am talking about

Ahh ok then.

No just needed to force water back into water heater has to overcome your supply water pressure ie Town or well system. Don't know BRS system waste % they conveniently don't list it although its obviously made by some manufacturer

And why does it need to do that if it wont improve the amount of waste water/RODI water? Someone said that its 3:1, 3gallons waste to 1gallon RODI, unsure if that's good or bad to other systems.

 

[Sisterlimonpot]

The water that is returned into the cold line by the booster pump does not go through the membrane.

I didn't suggest the rejected water goes back through the membrane. My concern was reintroducing the concentration of minerals and sediment back into the supply water line. It doesn't seem good for any plumbing system.

I get that when the narrow sighted goal is to reuse the waste water this seems to check the box. But does it?

Again read about it.

I'll admit, I was going off of how you explained it and as yesterday dragged on, I had more questions so I did breifly look it up and aside from the initial concerns I had, I now I have more questions.

Does the booster pump run off of pressure differential? Or is it on when the rodi is in operation?

Where does that extra water go when you're not using hot water? Am I to assume that your hot water side is capable of expanding to displace the extra water injected?

From an engineering perspective, my 1st choice would be to over pressurize the hotwater side because hot water heater come equipped with pressure relief valves to deal with expanding water.

Does that mean that this is a gimmick and all that water is really wasting out of the pressure relief?

If not, how does the system prevent over pressure? I guess it can leach backwards into the city supply, which would be a huge red flag. That means your neighbors are getting higher TDS in the potable water supply? How can that be legal? And if true, I don't see any cost savings for the user. You're still paying for the waste water and giving it back for free only to use a small portion when you run your hot water during times that the RODI is on.

I have had it for 6 years nothing has exploded things such as valves are built solid anything tested has to withstand 1.5 times the expected operating pressure.

As long as you're hotwater heaters relief valve is in working order, I would tend to agree with you. In fact, if I had one of these systems, I would put a bucket on the end of the pipe connected to the hotwater relief valve and occasionally check it to confirm/deny my theory.

people would research before voicing personal opinions instead of reading about what an actual ENGINEER developed.

For me, this is the scary part, advertising clouding percieved "sound engineering science". Which is simply an attempt at marketing taking advantage of consumers lack of understand hydraulics. Sprinkle in something that makes enough sense that the rest of what is said can be lumped into a sales pitch.

Let someone decide for themselves I chose not to put extra footprint on the worlds water supply .

I'm all for coming up with ways to conserve water. But this seems like it's done at the owners expense of shortening the life of hotwater heaters, fixtures and seals. Being active duty military and moving around a lot, I've owned 4 houses in my day and I wouldn't put one of these on a house I owned. It's bad enough spending money on plumbing upkeep, I definitely don't want to increase that budget to save some water. But you're right to let the consumer make their own decision but don't you think they need to at least be fully aware of what's really happening?

A normal RO wastes more than it makes

To push back, there are RO units out there that have better rejection rates than others, in our hobby people tend to purchase the rebranded BRS version which isn't the best candidate for conserving water. As mentioned Spectrapure offers some more efficient units that waste less water. But if we're being honest with ourselves, is the few gallons a week savings enough to justify speeding up the buildup in your hot water supply side?

In my opinion, I think you can route the water to a garden or your washing machine and utilize the water that way. And if you truly want to strip TDS from water, why not ditch the membrane altogether and simply use DI to achieve 0 TDS? That seems more along the lines of what a conservation savvy person would gravitate towards anyway.

 

[Randy Holmes-Farley]

Is that normal, that seems like a lot haha?
What pump is important?
If the rate of water production is increased, does that mean the rate of waste is also increased? or does it improve with the booster so it could get to 2:1 or whatever.

Trying to reduce waste water is not a win win. It has drawbacks of various sorts.

The entire RO/DI process is detailed here:

Reverse Osmosis/Deionization Systems to Purify Tap Water for Reef Aquaria by Randy Holmes-Farley - Reefkeeping.com

 

[Randy Holmes-Farley]

Ahh ok then.


And why does it need to do that if it wont improve the amount of waste water/RODI water? Someone said that its 3:1, 3gallons waste to 1gallon RODI, unsure if that's good or bad to other systems.

It's in the typical range. I really think this focus on waste water and booster pumps without knowing if it is needed is just confusing things.

 

[Freenow54]

I didn't suggest the rejected water goes back through the membrane. My concern was reintroducing the concentration of minerals and sediment back into the supply water line. It doesn't seem good for any plumbing system.

I get that when the narrow sighted goal is to reuse the waste water this seems to check the box. But does it?


I'll admit, I was going off of how you explained it and as yesterday dragged on, I had more questions so I did breifly look it up and aside from the initial concerns I had, I now I have more questions.

Does the booster pump run off of pressure differential? Or is it on when the rodi is in operation?

Where does that extra water go when you're not using hot water? Am I to assume that your hot water side is capable of expanding to displace the extra water injected?

From an engineering perspective, my 1st choice would be to over pressurize the hotwater side because hot water heater come equipped with pressure relief valves to deal with expanding water.

Does that mean that this is a gimmick and all that water is really wasting out of the pressure relief?

If not, how does the system prevent over pressure? I guess it can leach backwards into the city supply, which would be a huge red flag. That means your neighbors are getting higher TDS in the potable water supply? How can that be legal? And if true, I don't see any cost savings for the user. You're still paying for the waste water and giving it back for free only to use a small portion when you run your hot water during times that the RODI is on.



As long as you're hotwater heaters relief valve is in working order, I would tend to agree with you. In fact, if I had one of these systems, I would put a bucket on the end of the pipe connected to the hotwater relief valve and occasionally check it to confirm/deny my theory.


For me, this is the scary part, advertising clouding percieved "sound engineering science". Which is simply an attempt at marketing taking advantage of consumers lack of understand hydraulics. Sprinkle in something that makes enough sense that the rest of what is said can be lumped into a sales pitch.


I'm all for coming up with ways to conserve water. But this seems like it's done at the owners expense of shortening the life of hotwater heaters, fixtures and seals. Being active duty military and moving around a lot, I've owned 4 houses in my day and I wouldn't put one of these on a house I owned. It's bad enough spending money on plumbing upkeep, I definitely don't want to increase that budget to save some water. But you're right to let the consumer make their own decision but don't you think they need to at least be fully aware of what's really happening?


To push back, there are RO units out there that have better rejection rates than others, in our hobby people tend to purchase the rebranded BRS version which isn't the best candidate for conserving water. As mentioned Spectrapure offers some more efficient units that waste less water. But if we're being honest with ourselves, is the few gallons a week savings enough to justify speeding up the buildup in your hot water supply side?

In my opinion, I think you can route the water to a garden or your washing machine and utilize the water that way. And if you truly want to strip TDS from water, why not ditch the membrane altogether and simply use DI to achieve 0 TDS? That seems more along the lines of what a conservation savvy person would gravitate towards anyway.

I did add these for when not in use. The t and p is set for 150psi to answer that. As I said earlier new homes come with a backflow preventer sometimes integral in the meter. If just for fun someone fills their above ground pool up and leaves the hose in it and same skunk drowns in it and the town water supply looses pressure the backflow preventer stops the pool from siphoning back into the town water. I don't make these things up. also suggested if a sewage flood in basement and hose or whatever underwater. What are the chances of that? But must have happened because someone decided to make it part of the building code. Also new homes here have to have an undefeatable temperature limiter otherwise known as a mixing valve installed off water heater to protect the innocent ie people that will sue because someone did not wipe their nose for them

 

[SaltWaterTank_Noob]

It's in the typical range. I really think this focus on waste water and booster pumps without knowing if it is needed is just confusing things.

Hahaha yeah, it for sure is. I think I've decided to just go with the BRS 75gpd RODI system that has the TDS tester and pressure gauge and then go from there. BUT I am needing to decide if I should put it under my sink (which since theres not much room, I would need to take it on and off whenever I am using/not using it) or if I should connect it to my electric tankless water heater and then I can leave it there indefinitely and its closer to my tank than my sink, roughly 30-50ft.

 

[Sisterlimonpot]

I think i get it now, so without the booster then the "waste water" from the RODI system will go back into the hot water line BUT if you have the booster, then it allows the "waste water" to just bypass going into the hot water line and will go through the filter again so it cleans it and can be used?

@SaltWaterTank_Noob, it seems that this side discussion is confusing you to what should be simple.

Your questions are that of anyone coming into the hobby and trying to navigate the subject of RODI.

The 2 options that you mentioned in your 1st post are common. And based on your question it seems you're budget savvy. I will offer my thoughts in hopes to steer you into making an informed decision.

The RODI buddy is definitely a budget friendly option, however when it comes time to service the filters you're subject to their proprietary filters and their pricing. The BRS version uses traditional size filters that can be purchased from unlimited suppliers. The extra upfront cost needs to be weighed with longterm use and servicing.

As for chloramine or chlorine, that is handled on the prefilter side (sediment > carbon block). Choosing the right carbon block with the right micron filter will address chloramine concerns. I assume that my water supply has chloramine and purchase the correct carbon blocks.

As the thread progressed you had other questions about rejection rate, and that's where RO units separate. There are companies out there who's business is water filtration. They focus more on efficiency and differing mixtures of DI for reef tanks. You mentioned that Spectrapure is double the cost of the leading brand and I believe that's because they make a superior product.

That doesn't mean you should rush to buy their units, it's more of understanding the differences. Their membranes/flow restrictor can fit into most RO housings to provide a better rejections rate. And the same goes for their prefilters and DI.

However, if you go with the rodi buddy, none of those can be an option. At the very least you should consider purchasing a unit with universal canister sizes.

I hope the side conversation of zero waste isn't muddying the waters for you... sadly I fear that it's has.

 

[Randy Holmes-Farley]

Hahaha yeah, it for sure is. I think I've decided to just go with the BRS 75gpd RODI system that has the TDS tester and pressure gauge and then go from there. BUT I am needing to decide if I should put it under my sink (which since theres not much room, I would need to take it on and off whenever I am using/not using it) or if I should connect it to my electric tankless water heater and then I can leave it there indefinitely and its closer to my tank than my sink, roughly 30-50ft.

If that second use is cold water before heating, I'd go that way. If it is heated water, some other option will be better.