Does anyone know what the pros and cons of RO water (for aquarium use) are?

Answer 1

Off the top of my head:

Pros: No heavy metals
No ammonia
No chlorine/chloramine
No other impurities
Softened water

Cons: Sometimes, the water is too soft for the fish
Usually too pure for fish use - will need to buy trace elements to add to the water to promote a healthy environment
Usually too acid for most fish - will need to use a pH stabilizer for most fish

Honestly, if you're going to use RO water for your fish, I'd do a half and half mix of the RO water and tap water. Then you can usually get away with the extra chemicals (the trace elements and the pH stabilizer) and have stable water for your fish.

Answer 2

Pros: Your water should be free of impurities.

Cons: The buffering capacity of your water will be diminished since there will be little to no calcium compounds in your water. This will make the PH level unstable and it will most likely fluctuate fairly easily.

You could buy a buffering compound to solve this issue.

It really depends on what type of tank you are running. Salt Water tends to be more tempermental than fresh but your results may vary depending on fish species or plants. Some species like softer water, some like harder water.

I live in an area that has very hard water... I have a hard time keeping tetras and some other types of fish, on the bright side Cichlids are cool with it. Things like trace elements are only really necessary if you are growing live plants and possibly with some corals.

Good luck

Answer 3

I wouldn't worry about RO unless you are considering a Marine (saltwater) tank. RO is overkill for a freshwater tank. If what you are wanting to do is go with a water purifier for a fresh water system, then I would recommend something along the lines of H2O's products.

http://www.bidness.com/esd/us4_water_filter.htm

I bought the US4-IL that goes directly inline with my kitchen sink so I could do water changes all the easier. You never need to worry about water conditioner for Chlorine or Chloramine elements, and your water is pure - no hard elements of any sort.

It's a different story when you start going with live plants in a FW tank, but trust me - it's well worth it!

Answer 4

In general it's a idea bad if you have to ask this question. The long answer is it depends on how pure of water you get out of it, how hard you tap water is, and what fish you have/want. You should be looking at the KH requirements of your fish. Fish like molly like a high KH in the 10-25 range. Other like Discus, and Angel fish are in the 1 to 3 range. The real question is what is your current water's GH, and KH is and what fish you are planning on keeping? In some area for softwater fishes you may need it, and in others you don't.

Answer 5

RO water is what is used for saltwater aquariums, but you would be better off with bottled spring water for all other fish, they do require some minerals in their water for health.
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Answer 6

What's "R O" water?