RO/DI Water Questions

[JusJim]

If I set up a RO/DI system, would I just start adding that water to my saltwater tank as I do water changes, or do you need to totally drain the tank and start over with all RO/DI water?

Also, can the RO/DI water be used in your freshwater tanks. If the answer is yes, then should it be used in a freshwater tank.

TIA, Jim

 

[mcegelsk]

With saltwater, you can use straight RO/DI water as your top off water for the evaporation directly to your tank.

For water changes, once you mix the salt in and verify salinity (I use a refractometer) you can drain the tank to your desired level and refill with the newly mixed water. There is no need to drain the tank fully. However the more you change the better quality the water will be.

As for Freshwater...I'm not sure.

~Matt

 

[funman1]

Yes RODI water is great for freshwater too, however not nearly as necessary

 

[IslandCrow]

The one issue I've heard about using RO/DI water for freshwater is that you don't want to add it pure to the tank. I can't really explain the chemistry behind it, but basically what happens is that you purify it to such a degree that the molecules want to bind to something, and they will actually pull nutrients from your tanks inhabitants. . .i.e. your fish. This is also the reason you really don't want to make a habit of drinking too much distilled or RO/DI water (plain RO is fine). It does the same thing to your body.

Anyway, the problem is easily solved for freshwater. Just go to your LFS and buy some salt for freshwater tanks. I'm really not sure how it differs from the salt you buy for saltwater tanks other than you use a lot less, but it puts all the nutrients back in the water and you've started with high quality RO/DI, so you should be in good shape.

 

[mbbuna]

the salt water recommendations above are correct. as for fresh water it depends on what type of fish.for African Cichlids i use the water that comes from the waste line because they need hard water high in mineral content. if you do South American fish or Discus then i would use the RO end of it and reconstitute the water with what ever minerals you need to reach the ph ect for the fish you keep

 

[LowKey]

If I was a beginner, I would do several waterchanges over a month. Just to be sure the fish arnt effect by drastic parameter changes.