How pure is DI water from the store?

[Steve_B]

I make my own RODI water. My unit broke down and I ordered a new one instead of replacing the destroyed membrane and DI cartridge. This is a fish only tank with one large piece of white coral replica.
I use a wet/dry filter and the nitrate was about 20PPM before I started using DI from the grocery store while waiting for my new RODI. I have been using the DI for top off. It’s a 70 gallon corner tank with a 36 watt 12x UV sterilizer. I haven’t checked the nitrate while using the DI water but my coral has really started to grow brown and green algae in the interim. I figured the DI water from the store should be very pure with the same TDS reading of 000 PPM that my RODI makes. Does anybody know how pure the DI water from the store is?

Thanks in advance

Steve

[MuffsAbby]

If it's distilled water (not spring water or other bottled water), then it should be 0 TDS.

[jackde]

Water from the store would not be DI only RO.

[andrewey]

I doubt its DI water, and it's probably just RO

[Steve_B]

It says on the bottle;
DISTILLED WATER

They also sell “PUREFIED WATER,” which may be RO water which has been mentioned. I didn't use it because i have no idea what it is.

It really doesn't matter anymore now. My RODI unit just arrived. This was just thrown out there for future reference for anybody and me to have some reference point. I have a high quality TDS meter with 2 probes that can be placed anywhere I choose between any of the filtration components. I like to see what my carbon block output is before it enters the membrane so I’m aware of what point it is going over 000.0 TDS, so then I replace it. I use the second probe after the DI output to see where I stand as far as what the final out PPM.
I don't go by the directions on the RO unit.
Change every, blah blah blah, whichever comes first. I use the meter for accurate TDS readings that tell me when something is actually heading for replacement time. I couldn't measure the distilled water TDS because mine have probes that mount into the RODI lines.

[fdonophan]

I used distilled water for the first 9 months or so when I started my tank and had good luck with it. My usual water tests always came back clean. I stopped mainly due to cost, particularly since it was being delivered to my home, and purchased an RO. I had no issues using the different waters interchangably when needed.

[Steve_B]

I used distilled water for the first 9 months or so when I started my tank and had good luck with it. My usual water tests always came back clean. I stopped mainly due to cost, particularly since it was being delivered to my home, and purchased an RO. I had no issues using the different waters interchangably when needed.

Yea, if a person had a handheld TDS meter, distilled water should come up very pure

An RODI does reach the DI part of the unit as the last phase. I have a theory regarding this unwanted algae problem that will be put to the test soon.

I like it when theory becomes reality, makes me feel like Einstein, heeheehee

[Buckeye Hydro]

An RODI does reach the DI part of the unit as the last phase.

Say what?

[Steve_B]

Say what?

I have to make this quick, I’m in a hurry, I have 2 minutes to right this so there are probably lots of typos

TDS refers to TOTAL DISOLIVED SOLIDS. It is inherently full of minerals, in most cases, as far as I know. Any tap water goes through a municipal filtration plant and other chemicals or compounds will add additional TDS to the water, a lot more, lots more. Lots more. I asked my village, whatever they are called, for a print out to show me what is in their water. The list was 2 pages long, and I think one word was “sodiumcloriigeehilkeevegramintromofo”

I tried to Google it and my computer caught on fire.

An RODI first filter stage from the tap water is called the sediment filter. From the sediment filter it enters the carbon block. From the carbon block it enters the membrane. From the membrane it enters the DI part of the filter. The FINAL end of the RODI filter is referred to as the DI filter.
DI is DISTILLED WATER. RO means “REVERSE OSMOSES.” Thus, DI is the FINAL end stage that the RODI filters. That is the most filtered part of the water we mix with synthetic salt to become saltwater.
If you have a TDS meter the water out of the DI should read 000.0 PPM. PPM refers to PARTS PER MILLION. As far as I know there are no hobbyists meters available that will show PPM at a lesser amount, at least for an aquarium hobbyist. I'm sure they exist in labs for reasons that I don't know or care about.

I hope that clears things up.

[oklahoma11]

I believe that the light will go off on the canisters when the ppm reaches 40. so somewhere in between.

[MuffsAbby]

The DI in "RODI" does not mean distilled...it means de-ionized. Distillation is a totally different process of purifying water. You can purify water using either RODI (reverse osmosis & de-ionization) or distillation, but the two processes are not the same.

[Steve_B]

The DI in "RODI" does not mean distilled...it means de-ionized. Distillation is a totally different process of purifying water. You can purify water using either RODI (reverse osmosis & de-ionization) or distillation, but the two processes are not the same.

I didn't know that. I guess I've had the wrong knowledge for the several years that I have been making my own RODI water.
I thought that I’ve read that it is distallation. Maybe the word has been used incorrectly or I just wasn’t paying close enough attention.

Anyway,
Thanks for the info :thumbsup:
I don't like to go around stating incorrect information.

[Steve_B]

Say what?

Sorry about stating the incorrect information
:headwally:

[Steve_B]

I believe that the light will go off on the canisters when the ppm reaches 40. so somewhere in between.

What does this mean?
"the canisters when the ppm reaches 40"

This is the unit I had been using with my previous CORALIFE RODI SYSTEM for a few years. It has 2 probes.
After my RODI unit was filtering for several minutes the readings were both 0 PPM.
It's the DM-2 TDS Meter that is made by HM Digital. It comes factory calibrated.

http://www.bulkreefsupply.com/store/fm-2-filter-monitor-with-volumizer.html