Did I miss the memo on RO/DI vs Distilled?

[Big Chief]

Yes, I did a search on RO/DI... My title is a rhetorical question, :spin2:

Been working on this new tank for about 3 months now... Drawing upon my outdated knowledge of 15 years ago and the new knowledge from forums and books...

Currently I have been using distilled water for top off's. I average a 1g water loss each week. 40 gal tank.

Initially, I planned on doing water changes (roughly speaking) once per month and cleaning my Magnum Canister at the same time, replacing with carbon and a new sock.

After month 2, I realized the canister might need to be cleaned more often than once a month. Through research I see people recommend after 2 weeks to just rinse the media (USING RO/DI) and replace the sock.

All this time, I was under the impression that RO/DI systems were meant for bigger tanks... and my distilled water top off would be okay... Am I wrong?

Should I be using RO/DI for tops... and using RO/DI to rinse out my filter?

Just trying to get my bearings straight as I enter this hobby... Thanks.

[thegrun]

Either RO/DI or distilled is fine. It is a good idea to test the store bought distilled for TDS to be sure it is pure, but distilled works well.

[phenom5]

I think distilled and RO/DI are about the same quality-wise, with distilled being a little better. RO/DI is cheaper in the long run, regardless of tank size.

[redfishblewfish]

One additional point….I’m not a canister filter user and personally believe that they shouldn’t be used on reef tanks, but if need be, could get away using them with FOWLR or FO tanks if rinsed frequently. Anyway, the point I want to raise is that I would think you would want to maintain the biology in the canister filter. Accordingly, I believe you would have to rinse the unit with salt water. If you use any fresh water….RO/DI, Distiller or tap…..it will kill the beneficial bacteria that is present. I would suggest using the water you pull out during a water change to rinse the innards of the canister filter.

[jbax]

the reason you may have thought ro/di units were only for big tanks. is most people with small tanks don't think they need a ro/di unit, cause of the size of their water changes and so on.

i need a ro/di unit. my 135g evaporates 4g a day and my 54g evaporates 5g every 3-5 days.

[snorvich]

RO/DI is superior in quality to distilled. Since I go through about 200 gallons of water change per month and who knows how much top off, buying water would be prohibitively expensive and would not have the quality control I get from making my own.

[Misled]

RO/DI is superior in quality to distilled.

This. Unless you test every gallon of distilled. You can't say for sure what's in it. If you know the distillery, that may well not be true, but otherwise, RO/DI is the best way to go. Some distilleries used to use copper vats to store water in. Not good for a reef. If something gets in a storage tank at a distillery, it may not get caught in it's early stages. My RO/DI doesn't have that problem as I see what's going on with the filtration of the water. I don't rely on someone else to do it for me.

[krowleey]

I think distilled and RO/DI are about the same quality-wise, with distilled being a little better. RO/DI is cheaper in the long run, regardless of tank size.

could you explain how distilled is better than zero TDS lab quality water?

[karsseboom]

could you explain how distilled is better than zero TDS lab quality water?

distilled WATER IS ZERO AS WELL. people need to stop spreading false statements about distilled water. No they dont use copper anymore thats about 20 years old now. I have tested many many distilled water gallon and they all were zero. I have an ro/di unit and it test zero too so there about the same...

[EllieSuz]

Have a look at this unit. I've been using it for over a year and my TDS reading is still only one. The unit is $110 plus shipping and the replacement canisters are only $27.00. You don't mention how large your tank is, but this unit makes enough water for weekly changes and top-off in an afternoon for me. It's fully portable too and you can hook it up to a sink. I use mine in the laundry tub in my basement. Buying distilled water can get expensive compared to a unit like this.

http://www.airwaterice.com/product/1MMDI/Mighty-Mite-50GPD-with-DI-Added.html

[Misled]

distilled WATER IS ZERO AS WELL. people need to stop spreading false statements about distilled water. No they dont use copper anymore thats about 20 years old now.

This is not true. I know of one in PA. that still uses them. Even if they don't wherever the distilled is coming from, they don't have to produce 0 TDS water to call their water distilled. It just has to go through the process. That's part of the problem.

I'm not saying all distilled is bad. I have used it in the past myself. I'm saying, if you rely on someone else to make sure your water is 0 TDS, and you're not testing it yourself, when they have a problem at their plant and notice it a couple days later, they are not required to remove it from the shelves. It still went through the distilling process. There are no regulations that say distilled water has to be 0 TDS.

[dots]

The ability to control your water and have a level of certainty not fluctuating in quality and is without contamination, is the greatest reason to use RO/DI at home.

Distilled water can have volitiale compounds that have a lower evaporation level of water.

overtime, the cost of an RO/DI unit will be lower than that of Distilled when your time/energy/fuel to a back are considered and must be.

In addition, because you will have an available source for WC's you will do more, more regularly and as a result will have a much healthier tank and greater success in the hobby.

An RO/DI unit is probably the most important piece I bought for my tank and should have done it sooner myself.