RODI vs Distilled Water?

[wowkingjames]

Thanks for the info reefers.

 

[AZDesertRat]

You would use a pressure gauge or better yet two gauges to monitor for plugging and headloss. I have one before the sediment filter and the one at the membrane. When I start seeing a difference between the two gauges it means they are plugging and need replacing. Since I assume you don't have chlorination you wouldn't need to monitor for chlorine breakthru with a low range chlorine test kit.

 

[Walter Mager]

AZ you have a picture of your setup?

 

[AZDesertRat]

Not handy but I can find one or take another when I get home. It's a Spectrapure UHE-100 with a couple minor modifications.

 

[Walter Mager]

Awesome...thanks!

 

[airwaterice]

Walter - no bullet biting! 30+ years experience helping reef club members just like you...I could get you up and running for less than $65 bucks.....

To be sure, you need a new membrane. We replace membranes when less than 90% rejection or if let to dry out after being wet. The dow filmtec 75 gpd I sell will very likely get you under 10 ppm tds from 900....a major factor in getting 99%+ rejection from your membrane is keeping your house pressure between 50-75 psi.

Expected results with your RODI unit, @50 psi & at least 1/2 gallon per minute flow...
STAGE 1: 5 micron sediment,
STAGE 2: 1 micron carbon,
STAGE 3: dow 75 gpd membrane
STAGE 4:10" refillable DI cartridge (Nuclear grade DI resin)
House tds: 900 ppm tds
RO tds: <10 ppm tds (99% rr)
DI tds: zero
My refillable DI cartridge will hold at least 3,000 ppm tds (stat is 6,000). This means if I take 3,000 divided by 10 ppm (RO tds)....this give you at least 300 zero tds gallons.

You can get this result with a constant 50 psi...if you have less than I would want a booster pump.

Pre-filters should be changed every 6-12 months or when a pressure drop is noticed. I sell a filterpack for your RODI for $25

Bulk resin will last several years if kept 1.) completely sealed, 2.) cool 3.) dry and 4.) completely out of the sunlight...IF you do these things for certain and are still experiencing poor results, I would question the quality of the DI resin.

In conclusion, my advice would be to NOT get another RODI unit as I am going to assume there are no problems with your RODI other than filters, membrane and the DI resin. But if you are interested...my typhoon 5 stage RODI is about $150...there is a reason about 1/2 of ALL the RODI units used for residential reef keeping have a Air Water & Ice logo...

Walter...do you have a water softener? Can you turn your pump up to 60 psi?

Always happy to help

 

[AZDesertRat]

A water softener is the absolute best thing you can do for a RO membrane. Membranes love softened water since it does much of the work for them and the membrane will function better and last much longer.

The second best thing is a booster pump, the higher the pressure the better the membrane will perform and the longer your DI will last meaning a lower cost per gallon of water produced.

AWI mentioned 30+ years in the industry which is awesome but I'm going on 41 years in the water treatment industry and am a certified water and wastewater treatment plant operator at the highest grades possible and have no connection or affiliation with any manufacturer, vendor or supplier so only recommend what has worked best for me in our high TDS and hard Arizona water.

I have personally owned and used RO and RO/DI units and filters from every major vendor, it's not only my profession but also my hobby to test these things side by side for comparisons so I have 4 systems running in my garage right now.

 

[airwaterice]

I recommend home depot for water softeners... I was there the other day and (as always) they have some under $500.

 

[Hunter S Thompson]

I happily and successfully use distilled water on my nano reef. 12 gallon tank with about 10 gallons of water. I change 5 gallons at a time (50%) every two months or so. I own an RODI unit but it's a portable one and IMO it's easier to just buy distilled for $0.80/gallon at grocery store and not worry about hooking it up, measuring the quality or volume of the output or changing filters. Easy and cheap water changes are one of the few benefits of a nano-reef.
Now RODI vs Distilled if you buy at store? If you trust the maker to properly distill the water then it should be nothing but H2O. I trust that more than I trust them to have a good RODI system. And even if they do have an RODI system in good heath, you hear of drugs from municipal water supply and chloramines passing. Neither is probably worth spending a second thought on though.
I suspect you could use nearly any water you get from the grocery store as long as it's not straight "spring water" (could be great but a gamble) or has "added minerals for taste". There are plenty of people that use tap water with success (I'm not recommending that).

 

[AZDesertRat]

With a nano distilled water is a viable option. Once your tank is a little larger or you do more frequent water changes though it becomes much more expensive. The average cost to make your own RO/DI water is around a nickel a gallon which includes replacement filters and DI resin as well as water and sewer rates. The 80 cents a gallon for distilled needs to include your travel time and vehicle expenses so ends up being much more expensive for a larger system.

As far as drugs and chloramines, neither is an issue for a good reef quality RO/DI system, they easily eliminate both of them no sweat.

I would never relinquish control of my water quality in my reef systems to anyone else if I owned a good RO/DI system, big step backwards.

 

[airwaterice]

I get endless calls from new customers wanting a zero TDS "RODI" water because their LFS's "RODI" reads >50 ppm with a TDS meter. There is no comparison. Buy a rodi for best quality rodi water at a fraction of the cost...If you have tank problems...non-zero RODI is one of the TOP culprits....and all you need is a tds meter that can be found for less than $20.