Experimenting with RO

The science behind successful fishkeeping
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Danmassey
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Experimenting with RO

Post by Danmassey »

Hi all
I'm going to trial mixing some RO water to see how tricky it is before deciding on the contents of my next tank, and just wanted to check I had things right in my head.

I'm going to try two containers, one pure RO and one mixing with tap water.

Essentially I think for a planted tank I should be aiming for a KH of 4-8 (so will aim for 6), a relatively low GH of around 6 as well.

From what I've managed to read there's a couple of things I'll need to add, I've looked at the Seachem products as they have good descriptions but will probably get a cheaper alternative.
So for the KH I will need go add an alkaline buffer agent (like sodium bicarb?)
For the GH a product like seachem equilibrium
Then I can't find many answers but some sort of trace element additive?

Trying to sort out a shopping list of what I'll need. Any help is appreciated as always!

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Re: Experimenting with RO

Post by Vale! »

If pure RO, and looking at your intended GH/KH ratio, I think you might consider using (something like) JBL Aquadur as the basis, and tweaking from there as/if necessary. You'd need a supplement of trace elements, such as Seachem Fresh Trace (which is what I use) or Discus Trace.

If diluting tapwater with RO, then you can just choose a RO/tapwater ratio to suit. Trace element supplement if you're not confident that there'd be enough range/amount of them in the resulting mix.

An alternative route would be the EI (Estimative Index) where you mix your own salts. The EI method is aimed chiefly at plants and does include calcium and magnesium salts, and trace elements (though, again, pitched at the needs of plants). You'd perhaps need something like potassium bicarbonate to tweak the KH bit - unless, like me, you're keeping softwater fish.

You'll be going for softwater-ish fish, though? It's maybe worth keeping in mind that the stuff you'll be putting in to feed your plants will be adding to the chemical soup in the tank. GH, while necessary to a greater or lesser extent, will be only part of that 'equation' of which it is a component. The 'softer' the 'softwater fish' involved, the more this becomes an issue (IMO). More on that later, perhaps, if you're curious!

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Re: Experimenting with RO

Post by Danmassey »

Great info thanks.
Yeah thinking of breeding annual killifish which like softer waters, and having a display tank. One of many ideas to be honest. Mainly I want to feel able to generate water conditions that I need before I plan any further.

I like the idea of EI dosing and will have a read. Probably only worth it if using a co2 system?

Edit- also is there a minimum amount of time to wait after mixing before testing?

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