Reconditioning RO/DI water for freshwater

[csrbmr]

Hi,

I am researching how to convert my 50 gallon freshwater aquarium from tap water to ro/di. I am trying to keep more sensitive fish species and my tap water is not conducive to doing so. What products to you recommend for adding minerals back into the water for a freshwater, non-planted tank. I did read a little about Equilibrium, but I'm not sure how this would affect a non-planted tank. Would it encourage algae growth? Also, I want a target ph of 6.5. It is my understanding that I can just use the recommended ratio of Acid/Alkaline buffer to stabilize the ph in this range. Any advice you can give in regard to minerals, etc would be appreciated. I have kept this tank for 3 years on tap water and I'm just not satisfied with the results. Thanks!

[csrbmr]

After doing more reading, I've decided to go with Replenish for mineral replacement. However, I'm undecided on my Ph buffer. If it would be more stable, I might consider going with Neutral Regulator for a ph of 7. My tank is now 7.4, but I haven't replaced much water with RO/DI yet. Is the buffering capacity of Acid/Alkaline buffer strong enough to prevent ph swings? For a RO/DI tank that is NOT planted, what buffer(s) do you recommend? I have had algae problems with my tap water in the past....but hope that this won't be an issue with RO/DI water.

Thanks!

[Tech Support EH]

Good morning, csrbmr.

I apologize for the delay in response, as we were not available over the weekend. I do think that, for your situation, Replenish is the best product for the remineralization of your RO/DI water. Replenish was designed to reconstitute minerals stripped from water during the reverse osmosis/ deionization process. These minerals are essential in osmoregulation of freshwater fish. While Equilibrium will also replace minerals/ restore general hardness, Replenish was designed with freshwater fish in mind, while Equilibrium more specifically targets the needs of aquatic plants.

As far as buffering is concerned, there are two different systems that work in freshwater. The first is a carbonate/bicarbonate system, and the other is a phosphate-based buffering system. Of the two, phosphates provide more overall pH stability. Because your tank is not planted, then I would suggest going with either Neutral Regulator alone or a combination of Neutral Regulator and Acid Regulator. These are phosphate-based buffers, while Acid Buffer and Alkaline Buffer are carbonate-based, so I think your pH would be more stable utilizing these.

So, if you would be happy with a pH of 7.0, then you can go with Neutral Regulator alone. Because your tank is at 7.4 right now, then you may need to add the suggested amount of Neutral Regulator daily until the pH stabilizes at 7.0, at which point you can just add the buffer on an as-needed basis.

If, however, you want to target a pH of 6.5, like you mentioned in your first post, then you can combine Acid Regulator with Neutral Regulator. Using 1 dose of Neutral Regulator and 2 doses of Acid Regulator will set your pH closer to about 6.4.

We hope this information helps, and please let us know if you have additional questions. Have a nice day.

[csrbmr]

Thanks so much for your reply. I think I will be happy at a ph of 7. Two more questions...will using Neutral Regulator greatly increase my algae problems if all my other water parameters are good? Also, my dKH is only about 3 (50 ppm??) right now. Will the Neutral Regulator increase the KH and will I be able to accurately measure it with my API KH/GH test kit?

Thanks!

Kristen

[Tech Support EH]

Hi Kristen!

Because your source water will most likely not have phosphates, and you will also not have very intense lighting for plants, nor will you be dosing any fertilizers, I don't think that the Neutral Regulator will give you any problems with algae.

Neutral Regulator will not contribute to KH, or carbonate hardness, though it will add to your total alkalinity, which would be evident on a total alkalinity test kit.

For conversion purposes:

1meq/L = 2.8 degrees =50ppm(mg/L)

Have a good one!

[csrbmr]

Okay, thank you. I want to make sure I'm understanding you correctly. My API test kit will not work with Seachem Regulator to measure my buffering capacity, correct? Do you make a freshwater total alkalinity test, or do I use the marine one? What do you recommend?