How much RODI system do I really need?

[ElZesto]

Hi Reef2Reef, I've got reef tanks that I've been running off of RODI water bought from my LFS for around 6 months now, and am really enjoying the hobby. I think I'm getting to the point of wanting to have RODI water on hand. The thing is, I don't really understand how many stages/what I need exactly. As I understand it, the filters seem to come in 3-7 stage systems, and various levels of 'efficiency' from there. I live in Portland, OR, and our water is allegedly very clean from the tap. It's so clean that apparently my roommate who runs fresh water was having trouble growing things in his tapwater tank due to lack of minerals in the water. Heres the report from the most recent water report from the city:

As I understand it I'll need:
An RODI system (??? stages)
A cheap water meter from amazon (to keep track of the amount that I use so I can pay for it, have roommates)
A 50gal trash can to store the RODI water in

Is that it? Idk, the whole thing seems expensive and overwhelming so I'd really appreciate someone whos done this (hopefully somewhere else with pretty clean tap water to start) to chime in.


Thanks and happy reefing!

 

[ElZesto]

For reference, I just tested my tap with a tds meter and it reads 25-28ppm tds. I assume like the minimum 3 stage will work?

 

[LPS Bum]

I live in Denver Metro and we also have low TDS water (40-60). But the amount of TDS isn’t as important as what makes up that TDS (arsenic anyone?).

I’ve used a standard 75 gal per day 4 stage RODI for many years. Sediment filter, carbon block, membrane and DI resin. Works great. I make 20 gal of RODI about every 8-10 days and that gives me top off water, water change water and kalk water. It all depends on your needs, but unless you’re burning through tons of water, a typical 4 stage like mine will work well.

 

[ElZesto]

Gotcha. I’ve read we use chloramine, not chlorine, so it will likely need more filtering? Idk this is a learning process lol.

What 4 stage? It the cheap RO buddy style or a standard canister style one like BRS?

 

[Idech]

I also have a 4 stage RODI unit (100 GPD).

 

[C_AWOL]

Salt and freshwater a pretty different since the basis of your minerals comes from the salt mix itself.
All that extras may be undesirable (phosphates in particular) being removed will reduce some long term headaches.

That said, any ro+di system will work just fine. Extra stages which include an additional carbon (2 total) would be better for water with chloramine and units with more than 1 di resin stage allows for you to fully exhaust the prior di stage before changing prematurely (to avoid 1+ppm tds) or allows you to utilize more of a specific resin for reduced resin change out.
Extras like a flush valve will improve the ro membrane lifespan and help deal with tds creep when done regularly (improves di longevity) and built in tds meters help you determine when filters and resins should be changed.

 

[ElZesto]

Salt and freshwater a pretty different since the basis of your minerals comes from the salt mix itself.
All that extras may be undesirable (phosphates in particular) being removed will reduce some long term headaches.

That said, any ro+di system will work just fine. Extra stages which include an additional carbon (2 total) would be better for water with chloramine and units with more than 1 di resin stage allows for you to fully exhaust the prior di stage before changing prematurely (to avoid 1+ppm tds) or allows you to utilize more of a specific resin for reduced resin change out.
Extras like a flush valve will improve the ro membrane lifespan and help deal with tds creep when done regularly (improves di longevity) and built in tds meters help you determine when filters and resins should be changed.

Ok that makes sense… I think. Thank you for the clarification on carbon stages vs more di resin stages. Does that mean 2 di resin stages consumes less resin than having one stage and replacing it? Or it more of a matter of convenience, since you have to perform a resin change half the time since there’s 2?

How do I know if I need two stages of carbon? Do I have to just go right off the bat with a system that has two, is it reasonable to get a 4 stage and then add another carbon if it doesn’t come out at 0tds?

Thanks for your time, I really appreciate the knowledge!

 

[C_AWOL]

Personally I would opt for a unit with 2 carbon blocks on any water source that utilizes chloramines. Stray chlorine will damage your membrane and affect performance. The end result of getting 0 tds is due to the di stage since ro membranes at peak performance and optimal pressure will only reduce it by up to 98-99%

To keep it as simple as possible, 2 di resin canisters is largely going to be a feature of convenience (theres varying levels of reduced consumption but its best not to over think it)

At least comparing the prices of brs units (without their common sales or considering other possible less expensive alternatives)
I find it extremely worthwhile to grab the $270 5 stage premium (2 carbon blocks + flush + pressure gauge + built in tds meter) over the $200 4 stage value (1 carbon block and no extras)

 

[Ryan - Serious Reefs]

I just shared this on a different thread but figured it would be valuable to you as well.

Keep in mind that this isn't a forever decision. You can always add a can to either side down the road. After messing with these for a decade plus this is my take but 5 stage is probably the sweet spot of cost and performance for most people.

3 Stage RO: ~ 50 times Better than tap water. Outside of easy to treat disinfectants, the biggest issue with tap water is often sky high calcium and alkalinity. To a moderate degree, nitrate and phosphate. The RO only system is going to remove a vast majority of the disinfectant, calcium , alkalinity, nitrate and phosphate. There will be some left over but once diluted in the tank it is typically not a big deal.

4 Stage RO/DI: Somewhat better than RO only. The DI's biggest advantage is just peace of mind. You got the last 2% and using ~lab quality water. I'd use this if I had some nasty contaminants like chloramines, copper, arsenic or ammonia gas. Reality is most of us have one of these so RODI has become the defacto solution for purifying freshwater for reef tanks.

5 Stage RO/DI: Dual carbon is what I recommend to my friends as longs it fits in their budget. Why two carbon blocks? Carbon blocks are far from 100% effective and let more disinfectant through the longer they are are on. Running two in series means the first dramatically reduces the disinfectant the second has to deal with and becomes very efficient. Typical blocks are near useless on chloramines as well.

6 Stage RO/2DI: Only real value for me is I don't have to monitor the exhaustion point of the DI resin and avoid the purge.

7 Stage RO/3DI: The Cation > Anion > Mixed Bed resin configuration does produce higher quality water. Mostly because the different stages have major pH differences that change the form of some contaminants like Ammonia or Silica and makes them easier to remove. I think that value is negligible unless you nerd out on water quality. The biggest value comes from more efficient use of resin. In a typical mixed bed the Anion resin runs out way before the cation does so you throw away perfectly good cation resin. When you separate them in the 7 stage configuration you only change the one that needs it. For me that is typically 5:1 meaning for every 5 anion cartridges I only use one cation. Another benefit is resin swaps and overall maintenance is reduce and why I typicality use 7 stages.

This is a summery of decades worth of researching, building, using and creating videos on RO/DI. Hopefully it is helpful :)

 

[LPS Bum]

Gotcha. I’ve read we use chloramine, not chlorine, so it will likely need more filtering? Idk this is a learning process lol.

What 4 stage? It the cheap RO buddy style or a standard canister style one like BRS?

Sorry, just saw your reply. I use an old Marine Depot Kleanwater 4 stage RODI (the standard canister style), which is basically the same thing as the more recent BRS version. You can add a second carbon block if you want for the chloramines (making it a 5 stage system), but I haven't found that to be necessary for me.

 

[LPS Bum]

I just shared this on a different thread but figured it would be valuable to you as well.

Keep in mind that this isn't a forever decision. You can always add a can to either side down the road. After messing with these for a decade plus this is my take but 5 stage is probably the sweet spot of cost and performance for most people.

3 Stage RO: ~ 50 times Better than tap water. Outside of easy to treat disinfectants, the biggest issue with tap water is often sky high calcium and alkalinity. To a moderate degree, nitrate and phosphate. The RO only system is going to remove a vast majority of the disinfectant, calcium , alkalinity, nitrate and phosphate. There will be some left over but once diluted in the tank it is typically not a big deal.

4 Stage RO/DI: Somewhat better than RO only. The DI's biggest advantage is just peace of mind. You got the last 2% and using ~lab quality water. I'd use this if I had some nasty contaminants like chloramines, copper, arsenic or ammonia gas. Reality is most of us have one of these so RODI has become the defacto solution for purifying freshwater for reef tanks.

5 Stage RO/DI: Dual carbon is what I recommend to my friends as longs it fits in their budget. Why two carbon blocks? Carbon blocks are far from 100% effective and let more disinfectant through the longer they are are on. Running two in series means the first dramatically reduces the disinfectant the second has to deal with and becomes very efficient. Typical blocks are near useless on chloramines as well.

6 Stage RO/2DI: Only real value for me is I don't have to monitor the exhaustion point of the DI resin and avoid the purge.

7 Stage RO/3DI: The Cation > Anion > Mixed Bed resin configuration does produce higher quality water. Mostly because the different stages have major pH differences that change the form of some contaminants like Ammonia or Silica and makes them easier to remove. I think that value is negligible unless you nerd out on water quality. The biggest value comes from more efficient use of resin. In a typical mixed bed the Anion resin runs out way before the cation does so you throw away perfectly good cation resin. When you separate them in the 7 stage configuration you only change the one that needs it. For me that is typically 5:1 meaning for every 5 anion cartridges I only use one cation. Another benefit is resin swaps and overall maintenance is reduce and why I typicality use 7 stages.

This is a summery of decades worth of researching, building, using and creating videos on RO/DI. Hopefully it is helpful :)

Nice write up Ryan. Some very good info here. BTW, I'm enjoying my membership to Serious Reefs. Looks like a bunch of new videos just dropped. Keep up the good work.

 

[ElZesto]

Personally I would opt for a unit with 2 carbon blocks on any water source that utilizes chloramines. Stray chlorine will damage your membrane and affect performance. The end result of getting 0 tds is due to the di stage since ro membranes at peak performance and optimal pressure will only reduce it by up to 98-99%

To keep it as simple as possible, 2 di resin canisters is largely going to be a feature of convenience (theres varying levels of reduced consumption but its best not to over think it)

At least comparing the prices of brs units (without their common sales or considering other possible less expensive alternatives)
I find it extremely worthwhile to grab the $270 5 stage premium (2 carbon blocks + flush + pressure gauge + built in tds meter) over the $200 4 stage value (1 carbon block and no extras)

I just shared this on a different thread but figured it would be valuable to you as well.

Keep in mind that this isn't a forever decision. You can always add a can to either side down the road. After messing with these for a decade plus this is my take but 5 stage is probably the sweet spot of cost and performance for most people.

3 Stage RO: ~ 50 times Better than tap water. Outside of easy to treat disinfectants, the biggest issue with tap water is often sky high calcium and alkalinity. To a moderate degree, nitrate and phosphate. The RO only system is going to remove a vast majority of the disinfectant, calcium , alkalinity, nitrate and phosphate. There will be some left over but once diluted in the tank it is typically not a big deal.

4 Stage RO/DI: Somewhat better than RO only. The DI's biggest advantage is just peace of mind. You got the last 2% and using ~lab quality water. I'd use this if I had some nasty contaminants like chloramines, copper, arsenic or ammonia gas. Reality is most of us have one of these so RODI has become the defacto solution for purifying freshwater for reef tanks.

5 Stage RO/DI: Dual carbon is what I recommend to my friends as longs it fits in their budget. Why two carbon blocks? Carbon blocks are far from 100% effective and let more disinfectant through the longer they are are on. Running two in series means the first dramatically reduces the disinfectant the second has to deal with and becomes very efficient. Typical blocks are near useless on chloramines as well.

6 Stage RO/2DI: Only real value for me is I don't have to monitor the exhaustion point of the DI resin and avoid the purge.

7 Stage RO/3DI: The Cation > Anion > Mixed Bed resin configuration does produce higher quality water. Mostly because the different stages have major pH differences that change the form of some contaminants like Ammonia or Silica and makes them easier to remove. I think that value is negligible unless you nerd out on water quality. The biggest value comes from more efficient use of resin. In a typical mixed bed the Anion resin runs out way before the cation does so you throw away perfectly good cation resin. When you separate them in the 7 stage configuration you only change the one that needs it. For me that is typically 5:1 meaning for every 5 anion cartridges I only use one cation. Another benefit is resin swaps and overall maintenance is reduce and why I typicality use 7 stages.

This is a summery of decades worth of researching, building, using and creating videos on RO/DI. Hopefully it is helpful :)

Thank you both so much for the information, I really appreciate you guys! I'll just save up a few bucks and get the 5 stage then since it sounds like that's the ticket. I really appreciate y'all taking the time to write this out!

 

[Freenow54]

Hi Reef2Reef, I've got reef tanks that I've been running off of RODI water bought from my LFS for around 6 months now, and am really enjoying the hobby. I think I'm getting to the point of wanting to have RODI water on hand. The thing is, I don't really understand how many stages/what I need exactly. As I understand it, the filters seem to come in 3-7 stage systems, and various levels of 'efficiency' from there. I live in Portland, OR, and our water is allegedly very clean from the tap. It's so clean that apparently my roommate who runs fresh water was having trouble growing things in his tapwater tank due to lack of minerals in the water. Heres the report from the most recent water report from the city:

As I understand it I'll need:
An RODI system (??? stages)
A cheap water meter from amazon (to keep track of the amount that I use so I can pay for it, have roommates)

A 50gal trash can to store the RODI wate

r in

Is that it? Idk, the whole thing seems expensive and overwhelming so I'd really appreciate someone whos done this (hopefully somewhere else with pretty clean tap water to start) to chime in.


Thanks and happy reefing!

I like my NO WASTE water system by watts. Your roommates wont be happy nor will you when you realize that for every gallon of RO yo get 4 to 5 gallons go down the drain. That said the system is $ 500 Canadian for me dont know for you ( sold on Amazon ) but is in States. You will need a DI filter with resin, and as proved to me a UV light to add on. I suggest using 2 35 gallon containers always will have extra RO for top off of tanks due to evapourization. My system is slow however will get 35 Gallons in a day and a half. I am on town water from lake erie ( treated )this is my primary filter after 6 months. Dont believe everything you read .

 

[Ryan - Serious Reefs]

Thank you both so much for the information, I really appreciate you guys! I'll just save up a few bucks and get the 5 stage then since it sounds like that's the ticket. I really appreciate y'all taking the time to write this out!

Glad it was helpful :)

 

[rtparty]

I like my NO WASTE water system by watts. Your roommates wont be happy nor will you when you realize that for every gallon of RO yo get 4 to 5 gallons go down the drain. That said the system is $ 500 Canadian for me dont know for you ( sold on Amazon ) but is in States. You will need a DI filter with resin, and as proved to me a UV light to add on. I suggest using 2 35 gallon containers always will have extra RO for top off of tanks due to evapourization. My system is slow however will get 35 Gallons in a day and a half. I am on town water from lake erie ( treated )this is my primary filter after 6 months. Dont believe everything you read .

With my dual membrane system and a booster pump, I have around a 1:1 waste to good ratio. I can put out over 150 gallons per day if needed.

My kid wastes more water showering in a day than my RO unit sends down the drain in a month. I can find a dozen places to easily cut back water usage before I worry about my RO unit

 

[Freenow54]

With my dual membrane system and a booster pump, I have around a 1:1 waste to good ratio. I can put out over 150 gallons per day if needed.

My kid wastes more water showering in a day than my RO unit sends down the drain in a month. I can find a dozen places to easily cut back water usage before I worry about my RO unit

What make is it? zero is zero. I got tired of mine taking 20 minute showers. So I warned them 10 minutes that's it. Well Did not listen. I knocked on the door she pretended not to hear. I went down stairs turned off the hot water. She screamed I turned it back on. She did not talk to me for weeks. None of the three ever did it again. A customer of mine installed a timer

 

[Freenow54]

you have a dozen places 1 person why do I say that? multiply your waste by millions. Were in this place together Partner

 

[rtparty]

What make is it? zero is zero. I got tired of mine taking 20 minute showers. So I warned them 10 minutes that's it. Well Did not listen. I knocked on the door she pretended not to hear. I went down stairs turned off the hot water. She screamed I turned it back on. She did not talk to me for weeks. None of the three ever did it again. A customer of mine installed a timer

BRS 7 stage with the water saver dual membrane. Then I use the Smart Buddie booster

 

[BryanM]

Gotcha. I’ve read we use chloramine, not chlorine, so it will likely need more filtering? Idk this is a learning process lol.

What 4 stage? It the cheap RO buddy style or a standard canister style one like BRS?

I've been led to believe that you need to do more to remove chloramine from water with RODI units.

https://www.buckeyehydro.com/chloramine-special-rodi/

@Buckeye Hydro