Can I use RO/DI water for a freshwater tank?

[thebulkhimself]

Bascially my mate is starting a fresh water tank and I remember all the algae hassles I had with my freshwater tanks when I used to have them, now I have a RO/DI system for my reef tank and was wondering whether it would be suitable to use RO/DI water for his fresh water tank or do the fish need other things found in tap water????

[Loverotties]

The cleanner(TDS) the water the better!The Less thing to try and take out.

[Hop]

Yes, just use something like RO right for large water changes or additions. Top offs are fine without the buffer

[dobejazz]

Whiskey had told me not to use RO/DI in a freshwater tank

This is his explanation copied from another thread

I have always used tap water for this, normally with a drop or two of declorinator from my FW tank,.. and everyone I know has always used tap water as well.

RO/DI water is stripped of EVERYTHING, including it has no Alk, meaning it's subject to wide PH swings very quickly. It also has the issue of something called "Hungry water syndrome" it is in a very un-natural state, and it want's to pull minerals from it's surroundings. If you use it as the water in your car it can actually erode the block. This is also why they don't use copper fittings, or line past the DI part even in industrial applications,.. it's all PVC (The matenence man in our shop told me that little gem )

Tap water has always worked well for me! I'm sure there's a better sulution (like adding Alk and minerals back to RO/DI) but it sounds like a huge pain and I don't wana bother.

Whiskey

[Hop]

Originally Posted by dobejazz

Whiskey had told me not to use RO/DI in a freshwater tank

This is his explanation copied from another thread

I have always used tap water for this, normally with a drop or two of declorinator from my FW tank,.. and everyone I know has always used tap water as well.

RO/DI water is stripped of EVERYTHING, including it has no Alk, meaning it's subject to wide PH swings very quickly. It also has the issue of something called "Hungry water syndrome" it is in a very un-natural state, and it want's to pull minerals from it's surroundings. If you use it as the water in your car it can actually erode the block. This is also why they don't use copper fittings, or line past the DI part even in industrial applications,.. it's all PVC (The matenence man in our shop told me that little gem )

Tap water has always worked well for me! I'm sure there's a better sulution (like adding Alk and minerals back to RO/DI) but it sounds like a huge pain and I don't wana bother.

Whiskey

Very true!

This is why if you do use it, you want to use the RO right which supplies the minerals and buffers. RO/DI water is what you want to go with if you are trying to acheive certain parameters, pH, soft or hard water as you can buffer it whereas you cannot with regular water. It usually drops or rises to where you think you want it and then snaps back the next day. The other reason to use RO/DI on FW applications is if you do have such elevated paramters that you have massive algae issues despite good husbandry, since many of the elevated parameters can't be tested for accurately. This is why the FW world began using the estimated dosing routing. When using RO/DI with RO right, you know where the trace elements and minerals are at.

But if you can keep a healthy tank without needing to go through the hassle or you are not trying to keep discus or breeding fish, I would stick with the tap and a good conditioner

[JustDavidP]

I use the waste water for my koi pond, betta tank (2 1/2 gallon) and my blue crayfish tank at my office (Via Aqua 12 gallon).

I'd not use RO/DI because I like to keep planted tanks. There are zero minerals, nitrate etc. and I'd have to adjust the water to keep the plants going.

Dave

[thebulkhimself]

Thanks guys - as I suspected - any links on the latest theorys to fresh water tank filtering?

[Wiskey]

Originally Posted by thebulkhimself

Thanks guys - as I suspected - any links on the latest theorys to fresh water tank filtering?

There has been almost no progress in this area.

If you were keeping discus or african cichlids I would say use RO then buy the expensive chemicals to add back all the minerals,.. but for normal fish it is definitally not worth it.

The best advice I've got is if you are keeping a fish only tank don't go overboard with lighting,.. my 125G oscar tank was lit by only 40W of light.

If you are keeping a planted tank then get super fast growing plants,.. they will suck down the nutreants before the algae gets a shot at it.

Whiskey