Safe Water

HappyPotatoes · May 9, 2019

I've heard that RO/DI water is the only safe water for my aquarium. Could anyone give me a really basic explanation of what RO/DI water is, and how I can get some for myself?

Would it be possible for me to turn tap water into RO/DI water? And if so, what equipment would I need?

sbash · May 9, 2019

HappyPotatoes said:
I've heard that RO/DI water is the only safe water for my aquarium. Could anyone give me a really basic explanation of what RO/DI water is, and how I can get some for myself?

I wouldn't say 'only', but it (using RO/DI water) certainly sets you up for the best chances of success...

The simple explanation is that RO/DI water is just really heavily filtered water, that has been filtered in a very specific way. Here is a Wikipedia article for reference:
https://en.wikipedia.org/wiki/Reverse_osmosis

The two most common ways to get some for yourself would be to buy it, pre-filtered or just make it yourself... So, onto your other question...

HappyPotatoes said:
Would it be possible for me to turn tap water into RO/DI water? And if so, what equipment would I need?

Yes! Most of us do this.

You simply need an RO/DI filter, I use a four stage myself, which has a particle filter, a carbon filter, then the RO filter, then the DI filter. So get a four stage as the bare minimum.

You can buy theses from local water supply companies, The Home Depot (or whatever), BRS, Amazon, most LFSs can probably get them...

HappyPotatoes · May 9, 2019

Would an RO/DI filter from Home Depot be sufficient, since it wasn't made particularly for saltwater aquariums?

And would an RO/DI filter do the same stuff as a normal aquarium filter, but more?

LiveWire · May 9, 2019

Basically you use pressure that pushes water through a semipermeable membrane to remove impurities or inorganic solids from water. The Heart of an RO system is its membrane which houses a mesh screen with tiny holes and you are forcing H2O through the membrane which will reject larger sized atoms that cant fit through those holes but allows the H2O to pass through leaving for the most part pure water.

It is not very expensive to make your RO water at home. It is good to start by testing your source water and then building an RO system around that. If you need some help figuring it all out I will be happy to help you out. Just send me a PM.

sbash · May 9, 2019

HappyPotatoes said:
Would an RO/DI filter from Home Depot be sufficient, since it wasn't made particularly for saltwater aquariums?

Yes, I would not have suggested it otherwise

The Home Depot ones may, however, come as an under the sink kit in a lot of cases. Which you only need the filter, not the pressure tank and faucet.

HappyPotatoes said:
And would an RO/DI filter do the same stuff as a normal aquarium filter, but more?

No, an RO/DI filter is designed to strip as much as possible out of the source water; and an aquarium filter is designed to filter (
(something specific from) aquarium water.

The goal is to get as pure water as possible, then mix it up with your chosen salt mix. That way you know what you are putting into the tank.

Jekyl · May 9, 2019

I got this one as a cheap option.

https://www.amazon.com/LiquaGen-Reverse-Osmosis-Deionization-Portable/dp/B00LKF09IW?th=1&psc=1

It works great but my DI resin has to be changed about every 100 gallons. I do know that my water is pretty hard though, lots of calcium in it.

Flippers4pups · May 9, 2019

Depending on your local water supply, most add chlorine or chloramines as a disinfectant. Removing these is highly important as it's highly toxic to marine life. Local water supplies have levels of fertilizer, heavy metals....etc. these need to be removed as they are toxic as well.

RO units sold in big box stores don't have the deionizing capability. Deionizing resin removes what the RO unit can't.

jsker · May 9, 2019

Flippers4pups said:
Depending on your local water supply, most add chlorine or chloramines as a disinfectant. Removing these is highly important as it's highly toxic to marine life. Local water supplies have levels of fertilizer, heavy metals....etc. these need to be removed as they are toxic as well.

RO units sold in big box stores don't have the deionizing capability. Deionizing resin removes what the RO unit can't.

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