Distilled Water

Blew · Mar 19, 2019

Hello,

I’m new to saltwater and reef keeping and all that it entails.

I have read random spots on the web when doing research that using distilled water is perfectly okay. However, I just came across a post of someone saying PH level in their tank using distilled water killed their life stock.

Can someone help clear this up? Is using distilled water in 1 gallon jugs from Wal-mart, ok?

James M · Mar 19, 2019

Welcome to reef2reef !!!
It’s okay. Many people start with distilled water and then buy a RODI system

flchamp89 · Mar 19, 2019

Invest in a cheap TDS pen not all water labeled is what it says it is. A 2 second check before using is a good piece of mind.

monkeyCmonkeyDo · Mar 19, 2019

RO water dispenser at safeway...by me at least. Ive used distilled before. Specially when i started. Local tap around me isnt that bad anyway.
D

RandyC · Mar 19, 2019

flchamp89 said:
Invest in a cheap TDS pen not all water labeled is what it says it is. A 2 second check before using is a good piece of mind.

A TDS meter is not a good barometer for testing water quality. TDS will tell you how much ionized salts and minerals are in the water, but it says nothing about what kind or how much of one particular salt/mineral exists. Also, non-charged molecules like ammonia or chloramine will not show up on a TDS meter.

That said, there have been many people that have successfully run a reef tank using distilled water or even tap water. But, of course, your mileage may vary depending on the source of the water.

I personally use an RO/DI unit to ensure that I know what is going into my tank. Reefing is hard enough and for me it's not worth having an unknown variable to start.

flchamp89 · Mar 19, 2019

RandyC said:
A TDS meter is not a good barometer for testing water quality. TDS will tell you how much ionized salts and minerals are in the water, but it says nothing about what kind or how much of one particular salt/mineral exists. Also, non-charged molecules like ammonia or chloramine will not show up on a TDS meter.

That said, there have been many people that have successfully run a reef tank using distilled water or even tap water. But, of course, your mileage may vary depending on the source of the water.

I personally use an RO/DI unit to ensure that I know what is going into my tank. Reefing is hard enough and for me it's not worth having an unknown variable to start.

I agree but think there's value when BUYING water to see if how it reads.

stacksoner · Mar 19, 2019

I use distilled water and couldn't be happier. For me, it eliminated a lot of headaches and disasters I had with making RODI. I really hated flushing the membranes, checking up on/testing/troubleshooting, replacing, and ordering replacement filters, cartridges, resins, membranes. My system is much more stable now and I haven't had the green algae dust on my glass or one diatom outbreak since going with distilled.

stacksoner · Mar 19, 2019

RandyC said:
A TDS meter is not a good barometer for testing water quality. TDS will tell you how much ionized salts and minerals are in the water, but it says nothing about what kind or how much of one particular salt/mineral exists. Also, non-charged molecules like ammonia or chloramine will not show up on a TDS meter.

That said, there have been many people that have successfully run a reef tank using distilled water or even tap water. But, of course, your mileage may vary depending on the source of the water.

I personally use an RO/DI unit to ensure that I know what is going into my tank. Reefing is hard enough and for me it's not worth having an unknown variable to start.

What unknown variable may existi in distilled bottled water that you know for certain doesn't exist in your RODI water?

Dkeller_nc · Mar 19, 2019

Blew said:
Hello,

I’m new to saltwater and reef keeping and all that it entails.

I have read random spots on the web when doing research that using distilled water is perfectly okay. However, I just came across a post of someone saying PH level in their tank using distilled water killed their life stock.

Can someone help clear this up? Is using distilled water in 1 gallon jugs from Wal-mart, ok?

The person whose post you read clearly doesn't understand anything about chemistry. PH and buffering capacity are related, but they aren't the same thing. In the case of the distilled water, it has almost no buffering capacity whatsoever. So as soon as you add even a little bit of a buffering compound to it (in this case, seawater mix with some carbonate/bicarbonate and borate buffers in it), it will take on the pH characteristic of the concentration of those buffering compounds. In other words, it's just not possible for distilled water to make someone's tank pH change (at all).

RandyC · Mar 19, 2019

slewrock1 said:
What unknown variable may existi in distilled bottled water that you know for certain doesn't exist in your RODI water?

In a perfect world, distilled water should be great to use. The unknown variable that exists is that I have no idea what every bottlers' distillation process is and whether the upkeep of their process is consistent and reliable. Distilled water is not the same across stores and brands (some is actually RO).

But you're right, if things aren't setup correctly at home with my RO/DI unit, my water could be bad for my reef tank as well. But that's on me if I forget to change DI resin, a carbon block, membrane or sediment filter.