RODI Noob

[Rip3618]

I’m planning a tank upgrade and was going to invest in a RODI. But...my buddy with a large tank brought up a point regarding efficiency of a RODI. I’m going to quote what he wrote me, “There’s a place in Tarpon that sells RO water for .25 a gallon so it’s easier just to go there with 5 gallon jugs. The RODI filters are slow and waste a lot of water. I would estimate it makes 2 gallons of water and waste 5 gallons which, when making 50 gallons of RO water, is like wasting hundreds of gallons of water.”

To be honest, it’s seems like grabbing 20-30 gallons biweekly (very rough estimate) is not an inconvenience for me. Especially when compared to the increase of my water bill and the amount of waste water if using an at-home RODI. Of course, that’s if my buddy is correct.

Any thoughts?

 

[melanotaenia]

I refuse to lug bottles of water from anywhere to my apartment, so that would be a hard no from me. There are RODI systems that are more efficient and waste less water, and cost a lot less than 0.25 per gallon to run and maintain the replacement cartridges/membranes.

 

[lyscer]

I hate lugging jugs as well. For a while I would go to the fish store and get RO water. Then I started testing it and found that sometimes I would get water with a TDS of 10+ when they needed to change out their filters so I bought my RO unit. I decided to run some numbers to give you an idea of what I spend to help out your cause.

I buy pretty expensive filters, and I know that others spend much less. When my TDS starts to be 2+ I will replace all of my filters.
A couple of caveats that allow me to not run my system 100% of the time and allow me to only run it when needed.
1. I rinse my pre-filters around 6 months or when they start to look funky.
2. I use a flush valve religiously because I found it prolongs my DI resign significantly which cuts my costs down, and I only run my system a couple of times a week.
3. I have a 15 gallon reservoir that I use to get RO/DI water for my water changes
4. I have a 5 gallon ATO for my tank

System Specs
approx. 80gallon water volume in my Aquarium and I have a 5 stage RO/DI.

1. Sediment Filter
2. Carbon Block Filter
3. Carbon Block Filter
4. DI
5. DI

Replacement filters cost me ~$113.95 annually.
I evaporate approx 1gal/day. and perform a 10 gal water change every other week. Let's assume I miss 4 water changes in a year for 22 water changes in a year.
22*10gal = 220 Gal
1gal/day = 365gal
Total RO Annually: 585gallons
Cost Per Gallon: 113.95 / 585 = $0.19/gal
585*.25 = 146.25 so only a $32 savings by making it myself, but it is soo convenient!

Hopefully, my wall of text helps you out some.

 

[Ruben's Reef]

@Rip3618 I was getting my RODI and Salt water from an LFS closed to my house and everything was fine until I find out that their TDS was 38 and I start getting some algae on my tank. Then I bought a RODI Buddie 4 stage 50gpd on Amazon for $60 and start making my own water, saving $$ on trips and also knowing that I have 0 tds water. My water bill is from $28- $30 monthly.

 

[JP Reef]

I’m planning a tank upgrade and was going to invest in a RODI. But...my buddy with a large tank brought up a point regarding efficiency of a RODI. I’m going to quote what he wrote me, “There’s a place in Tarpon that sells RO water for .25 a gallon so it’s easier just to go there with 5 gallon jugs. The RODI filters are slow and waste a lot of water. I would estimate it makes 2 gallons of water and waste 5 gallons which, when making 50 gallons of RO water, is like wasting hundreds of gallons of water.”

To be honest, it’s seems like grabbing 20-30 gallons biweekly (very rough estimate) is not an inconvenience for me. Especially when compared to the increase of my water bill and the amount of waste water if using an at-home RODI. Of course, that’s if my buddy is correct.

Any thoughts?

I don't think it is more economical to have to waste gasoline to drive somewhere and back to pay them to waste hundreds of gallons of water. An RO/DI unit is very efficient compared to your buddies plan.

 

[lapin]

Thoughts:
When you make your own RODI water you know what you are getting.
Lugging water is not my favorite thing. Now if i could figure out how to not lug buckets of salt.
The "waste water" does not have to go down the drain. It can be used to water your plants, garden or lawn.

 

[Montiman]

I am in AZ and I don't worry about wasting water. Water is cheap. Keep in mind there is no way to not waste water. Either you are making dirty water at home or the place you buy it from is making dirty water. The advantages of making your own water include.

Control over quality
Continuous availability
Cheaper in the long run

+The easier something is to do the more you do it. When I have my own supply of RO/DI I use it to clean test equipment, drink (RO Only), clean around the house, and do more water changes. I would use it much more sparingly if I had to haul it from the store and back.

 

[LiveWire]

Its perfectly fine to buy water from a LFS if you are not in high demand of large amounts of water or its not an issue for you lugging jugs around. If you have a small tank I would say it may be more beneficial for you to just purchase your water.

Buying a RODI unit is not very costly especially if you build it to what your specific needs are rather than just buying a cookie cutter unit. A properly adjusted RO unit should produce one gallon of permeate and dump one gallon of waste concentrate. You can also piggy back a 2nd membrane and place the concentrate line into that one to cut down on waste even more.

Its all in how much you need how much room you have to store water. A nano tank setup can easily do very well just buying water but a larger setup takes much more water not to mention having ready mixed saltwater on hand for an emergency.

 

[phatduckk]

I setup a mini RODI station and it’s nice to just have it on demand. My kids keep me pretty busy so my time with my tank is after bedtime (aka when the stores are closed).

also I couldn’t imagine lugging more than 2 5 gallon jugs. It’s heavy and annoying lol

 

[Auquanut]

Lots of great comments. There is a considerable amount of up front expense in purchasing the unit. Then there's the cost of replacement cartridges and water consumption to consider.
For me the piece of mind that I get knowing that my TDS is zero, coupled with the convenience and ability to make water in an emergency outweighs what little added long term expense I will undoubtedly incur.
If you have an RO/DI system and you start having a problem, one culprit you can immediately rule out is your source water.
You can absolutely use water from the LFS, just make sure you completely trust the quality and consistency of quality of the water you're getting.

 

[Rip3618]

Thank you all for the info. Upfront cost of buying a RODI is not a concern. When my buddy referred to the amount of waste water and factoring in my water bill increasing we’re my concerns. Consider those concerns adios! When I upgrade I’ll buy a RODI and never look back. For now, my weekly 5 gal bucket fill-ups from my LFS for my nano will do. Thanks again!

 

[Jay Z]

If you keep your rodi from going into the sewer, outside for instance. You can ask for a separate water meter for sprinkler use. Cuts out the sewer charge, save up to 60% or so.

Besides that, lets do some quick math so you can understand what rodi actually cost per gallon.

I'm in michigan, my water bill is $4.38 per 1 unit (745 gallon)

So a actual gallon cost me .006 roughly. 10 gallons is .06. So 6 cents per 10 gallons. If you don't have the best rod unit and its running 1:2, you get 1 usable gallon out of 3. so 3 good gallons cost you 6 cents still.

So it cost 4 times more to purchase at a store than to make.

So if you bought 1000 gallons from the store, it would cost you $250
1000 made at home, even with a poor water ratio, would cost you $20 for the year. With sewer charges, around $50.

 

[MamaP]

Lots of great comments. There is a considerable amount of up front expense in purchasing the unit. Then there's the cost of replacement cartridges and water consumption to consider.
For me the piece of mind that I get knowing that my TDS is zero, coupled with the convenience and ability to make water in an emergency outweighs what little added long term expense I will undoubtedly incur.
If you have an RO/DI system and you start having a problem, one culprit you can immediately rule out is your source water.
You can absolutely use water from the LFS, just make sure you completely trust the quality and consistency of quality of the water you're getting.

Sorry, I don't mean to sound dumb, but what is TDS?

 

[Jay Z]

Sorry, I don't mean to sound dumb, but what is TDS?

Total disolved solids.

Total dissolved solids (TDS) is a measure of the combined total of organic and inorganic substances contained in a liquid. This includes anything present in water other than the pure H20 molecules. These solids are primarily minerals, salts, and organic matter that can be a general indicator of water quality.

 

[MamaP]

Total disolved solids.

Total dissolved solids (TDS) is a measure of the combined total of organic and inorganic substances contained in a liquid. This includes anything present in water other than the pure H20 molecules. These solids are primarily minerals, salts, and organic matter that can be a general indicator of water quality.

Oh! Thanks! I'd like to get an RO system for the house, but I'm guessing there has to be a specific way to do the DI part...

 

[Quietman]

Man, I love the thought of lugging water all around town. All that driving, seeing the town...stopping by and seeing friends who no doubt would love to help me out. Especially late on Sunday when I realize my ATO reservoir is out. I'm not into football anyway plus I probably need to pick up dinner..there's two birds with one stone and man, that's just good time management there. And think of all those weights I don't have to lift....25 cents a gallon has to be cheaper than a gym membership.

Kidding aside, I'm pretty sure waste water is made for the purchased stuff too, you just don't see it going down your drain. And as earlier poster said...driving isn't terribly efficient. Gas isn't 25 cents a gallon And one gallon of gas is 20 pounds of CO2 (think about that driving to work sometimes).

Yes, I love my RODI. And a side benefit...I think it's kinda cool having those tanks, turning those valves, doing periodic flushes on the membrane. Do have one word of advice - "float valves" - ok that's two words, but I'd put those two words right behind "yes, dear" as the most important two words for a successful marriage. Even for just filling 5 gallon buckets.

Tons of great videos on RODI, what they do and how they do it and good advice on the best setup for you. Just search YouTube for "BRS and RODI" grab a big 'ol bag of popcorn and enjoy - they are surprisingly entertaining but then again, I like flushing RO membranes.

Good luck!!!

 

[Anchor]

Oh! Thanks! I'd like to get an RO system for the house, but I'm guessing there has to be a specific way to do the DI part...

Di is a tank of resin After the RO unit.. it helps take out some of the ions that the carbon and RO cannot..

 

[RocketEngineer]

There are several places where you can get RO systems that can be connected for household drinking water and include the DI filter in a separate container with a secondary outlet that you can use to make tank water. I know BulkReefSupply sells such a system and I've seen them other places as well.

 

[MamaP]

There are several places where you can get RO systems that can be connected for household drinking water and include the DI filter in a separate container with a secondary outlet that you can use to make tank water. I know BulkReefSupply sells such a system and I've seen them other places as well.

Great info! Thank you!