RO/DI

First off, welcome to Aquaria Central! I hope you enjoy surfing the boards.

In the Marine world of fish keeping, yes, RO/DI water is an absolute necessity but in the Freshwater world it is not necessary. In fact in almost every case, tap water is preferred since it has all of the minerals and such that are needed in the aquarium water for freshwater tropicals and freshwater cold water fish such as goldfish and koi. You will have to add a declor to the water during water changes and when you are topping off due to evaporation. A good one to use is "Prime". If your tap water is to hard for the fish you want to keep such as angels or discus then you might want to do a mix of tap water and RO water so it is diluted and the fish will be happier.However, in most cases the fish will adapt to the PH and hardness of the water as long as it stays consistent. It just depends on what fish you want to keep. If you do use straight RO/DI water you will have to add back chemicals to the water since they are not in that kind of water( RO/DI ) and you will not need to add a declor to the mix since there will be no traces of chlorine or chloarmines.

So what size tank are we talking about here? What fish are you interested in keeping? How do you plan to cycle the tank? Fishless cycle or fishie cycle?

Marinemom

yeah, Don't use RO/DI water unless you have poor water quality, It does mean you need a conditioner such as Prime, but the minerals and such are needed for FW, even more so with planted tanks.

2112 said:

We have a water softener for the water in the house. I don't know if that matters or not.

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Yes it does.

If it is a typical water softener you add salts to the water softener in order to soften the water.

These salts can (and probably will) cause problems with tropical fish.

TR

2112 said:

Thanks for the replies. I am planning on a 90g tank and doing a cycle with fish. We have a water softener for the water in the house. I don't know if that matters or not. I still don't know what kind of fish I plan to keep. Right now I am just doing as much research as I can before I get this thing going.

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I would reccommend at least using a deionizer...

jones57742 said:

Yes it does.

If it is a typical water softener you add salts to the water softener in order to soften the water.

These salts can (and probably will) cause problems with tropical fish.

TR

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:iagree:
it is best if you have a water softener to bypass as it may cause issues for the fish.

The outdoor water spigots on most water softener setups already bypass the softener for the simple reason that salt is not good for the plants in the back yard. What that means to a fish keeper is that they can fill the tanks from those same outdoor spigots and not end up with a salt problem. I am more inerested in why you have a softener. If the water in your area is unusually hard and needs the treatment to be safe in your pipes, you may be someone who could benefit from blending RO with outside water when you add to your tanks. The specific blend would depend on how hard the raw water really is and which fish you are trying to keep.