Choosing between
distilled and
RO/DI (Reverse Osmosis/Deionization) water depends on your application, as both offer high purity but achieve it through different methods.
Core Differences
- Production Method:
- Distilled: Water is boiled into steam and then condensed back into liquid, leaving impurities like minerals and heavy metals behind.
- RO/DI: Water is forced through a semi-permeable membrane (RO) to remove 90-99% of contaminants, then passed through an ion-exchange resin (DI) to strip any remaining charged ions, often reaching a TDS (Total Dissolved Solids) of 0.
- Purity Focus:
- Distilled is highly effective at removing biological contaminants like bacteria and viruses due to the boiling process. However, it may still contain trace volatile organic compounds (VOCs) that evaporate at a similar temperature to water.
- RO/DI is the standard for "ultra-pure" water in sensitive applications (like reef tanks or labs) because it consistently reaches absolute zero mineral content.
(I cannot vouch for the accuracy of the above.)
As we know the net is famous for misinformation due to a lack of filtering of any sort. So, the first things I did after reading the post above about John Ellis water was to research it. This might interest folks in this respect.
United States of America
FEDERAL TRADE COMMISSION
Washington, D.C. 20580
April 28, 2020
WARNING LETTER
read it here
https://www.ftc.gov/system/files/warning-letters/covid-19-letter_to_dap_john_ellis_water.pdf
But science shows a benefit in using this type of water for treating a number of things. But, there is another aspect to consider here and that is the cost of such water, especially when using it in an aquarium.
Comparison Summary
| Method | Upfront Cost | Per Gallon Cost (Estimated) |
|---|
| Home Machine | $800 – $2,500 | ~$0.50 |
| Portable Bottle | $80 – $300 | Minimal (Electricity) |
| Tablets | $0 | $8.00 – $16.00 |
| Pre-bottled | $0 | $1.50 – $8.82 |
I then looked on the Ellis site for how much his machine will cost to buy. He sells it for $2,800. I beleive it uses electricity to produce the water. When I delved deeper into hyyrogen water research papers I read nothing in them which mentioned the 114
° Hydrogen Bond Angle Ellis touts for his product. From what I could discern the whole 114
° angle thing is likely more hype than anything else.
I read one paper from Brazil where hydrogen water was used to treat zebra danios for a specific bacterial infection. It worked well and the paper further stated that hydrogen water did no harm to the fish which were not infected when they were kept in it.
Evaluation of the Potential Use of Oxy-Hydrogen Gas for the Treatment of Lactococcus garvieae Infected- Zebrafish in Hydrogen-Rich Water Aquarium
My feeling is thst hydrogen water is effective for treating some diseases our fish might contract but that it does not make sense to use it full time year round. Since all the water in a tank needs to be some level of hydrogemized, it is much more effective to use it in an H tank if one can. It also seems to offer the most benefit when used for treating things or for use by high level athletes as opposed to using it all the time as one's sole water source.
So I would stick with my RO/DI unit if I still needed it. My TDS pen measured my output at 0 ppm when the unit was new. When the RO membrane starts to degrade from use I can see this because the TDS starts to rise. When it hits 10 ppm was when I replaced both the carbon and RO modules. I estimate that my 3-Stage 75 gpd RO/DI unit which cost me $140 produced over 1,000 gallons of water before I needed the new carbon and RO modules. I used about 12 gallons/week year round for the Altum 55 gal tank. But, in the winter months my brother uses several small home humidifier units which will eventually clog from the minerals in tap water which get left behind when one uses tap water.
I suggested he switch to using the RO/DI water I was making where he had switched to buying distilled water for about $1/gal. unless it was on sale. He used 4-6 gallons/day depending on how cold it was outside. The colder the air, the less moisture it can hold. After the first two years, I insited he buy a unit of his own. I would alternate which machine we used to make the water. Once one starts using such a device it is important not to let the RO membrane dry out, I was taught this would cause it to stop working. So alternating the units helped to insure the mebranes stayed wet. We use a portable unit with the input using a garden hose connector. The utility sink in my fish space has matching output type garden hose connection.
I used to take my unit with me to weekend events where I sold in the vendor room. I brought 20-25 gallons of pure water with me and then, using the Python assortment of adapters, I could use the hotel sink in my room to make more pure water for use over the weekend. I used a 50/50 mix of RO/DI and hotel tap water and doing so reduces my weekend fish losses to almost 0.
Ultimately, I decided to upgrade to the 4 stage unit with the added sedeiment filter as the first one in the input flow. Unfortunately, it was barely 6 months after I got the new unit that I sold the altums and no longer needed my unit and I sold it to a member in my fish club who loves it. do need pure water for a few things and I now store about 4 or 5 gallons for other needs. For exanple, I mix my own ammonium chloride solution for cycling using a dry form of ammonium chloride and pure water.
When we make pure water we have the output going into a 20 gal. Rubbermade garbage can. As the can gets fukk we pump the water into mostly 1 gal. jugs as they are easier for us to carry from where we batch the water to where it will be used. But I also have a few Home Depot 5 gal. buckets with lids and a 6 gal. water specific can for storing it as well as the 1 gal. jugs. We trnd average making about 25 gals/week over a year when we were both using it, Now only he needs it for winter and the annual production is now more like 600 or so. At this point we have made about 180 gals made and have about 30 on the shelf before it is time to make another load.
One last note on using an R)/Di unit. We have our own well, so the only water cost we have is running the pump that brings the ground water into the house where it goes into the cold water tank. This matters in terms of the cost since we cannot get muncipal water. We live in a 4 acre zoning area and it makes not sence for either water or natural gas to be delivered on a municipal basis. We power our back-up generator, gas cooking and the pool heater via propane delivered by truck and stored in tanks we own or rent on the property.
