Ro/di Unit For South American Tank

[NeonBlueLeon]

Hey folks,
 
I have been planning a South American tank.  As you may or may not know, the fish and plants prefer soft water and a lower pH.  The pH out of my tap is 7.8, very hard, and contains ammonia (chloramine).  I have been considering an RO/DI unit for water changes.  The fish I am planning on keeping so far are cardinal and/or rummynose tetras.  If I end up not being able to control the chemistry of my tank, I may just stick with the more adaptable neon tetras.
 
After getting water from an RO unit, I assume I will need to replenish the nutrients for fish and plants.  Has anyone used Seachem Equilibrium?  How well does it work?  Is there another product anyone could recommend to use with RO water for a planted freshwater tank with pH not exceeding 7.2?

 

[DrRob]

Firstly, you probably don't need one unless you're planning on breeding them, most of what you mentioned are farm bred. It's worth checking with your LFS what they keep them in, which will give you an idea.
 
Following that, seachem equilibrium does work, can be tough to dissolve (investment in a shake mixer that the body builders use to mix their protein shakes can help with dissolving calcium salts) but works. Personally I make my own, higher initial outlay, but much lower long term investment, however some people report better results with other chemicals.

There's also tropic marin salts, mosura shrimp mix and various others.
 
Or you can also cut back with dechlorinated tap water at a lower concentration. Defeats some of the point of using filtered water, but improves the costs and productivity. For that I personally would recommend that you use a TDS meter to get to the water you want, and they can be picked up for as little as £10.

 

[NeonBlueLeon]

Thanks for the reply Rob.
 
When I first started the hobby, I had heard that cardinals were wild caught only.  Have they managed to breed them in captivity now?  I don't plan on breeding them, but in the interest of keeping a South American tank with South American fuana and flora, a low pH is ideal and low hardness is ideal.  In addition to cardinals, I'd like to keep GBRs, cories, and a lot of SA plants.

 

[DrRob]

They're farmed nowadays. Still not perfect fish for an immature tank.
 
Agreed, they do suit low hardness, low pH conditions and RO is perfect for them, but it's the GBR's that are picky from what you've listed, not the cardinals.

 

[NeonBlueLeon]

My local water board's website claims the average pH out of the tap in our county is 8.2.  That is insanely high, and my SA fish will not appreciate that.  Do you think an RO unit will help lower the pH?  I think the high pH may be due to the chloramines added (based on the the general ability of amines to raise pH).