RO waters for Fish?

Question

I am Looking at getting an RO filter for my tap water which is particulary bad as i live in London.

I was only going to do half RO and half tap, but do i still need to add the elements to the RO water if i am still using some Tap?

Answer 1

It really depends why you are using a RO filter. Generally this only really needed for saltwater, or soft water fish like discus. Honestly I reccommend sticking with fish that match your water chemistry rather than trying to "fix" your water. Hard water has a lot of benefits. (For example pH changes are slower with hard water.)

PS- If you are mixing tap, and RO water just to reduce the water hardness you don't need to add anything to the water. A teaspoon of salt per 5 gallons might be in order, but other than that no. Note that table salt, or any salt fit for human consumption will work.

Answer 2

It really depends on the fish. RO water is essential for marine tanks but then the salt that is mixed in has a lot of elements added to it. If you use a natural substrate like aragonite you won't have to worry as much as it dissolves in the water, but to be safe I would recommend that you do every other water change with bottled spring water.
A

Answer 3

Personally I would save yourself a lot of money, and just go with a water purification unit like the ones from H2O systems. RO Water has all of the trace elements removed from it, where a water purifier just removes the Chlorine and Chloramine (and other crap that shouldn't be in water like Lead, Arsenic, Barium, Cadmium, Chromium, Selenium, Mercury, Iron and other metals).

Here's their site here in the United States...
http://www.bidness.com/esd/us413_water_filter.htm

Get the US4-IL unit (it goes directly inline with your cold water line underneath your sink which will make it easier for you to do water changes if you are using a Python No-Spill or similar product).

Good luck!