RO Water remineralization?

[JJenna]

I'm coming down to the day when I actually start planting my tank, placed my order for different kinds of plants to see which I like better with my dragon stone decor. While I have an RO system at home, I'm going to jump start the process by going to lfs and getting 20 gal of         RO  (?DI).

• Do I need to remineralize each type of water and if so, recommendations?
• What does the removal of dissolved solids do for my fish/plants?
• Is there a significant difference between RO and RODI?
• Do I also need to treat for chloramines? I'm leaning towards no because we have a 125 gal tank for a 6" RES that also has ~20 fish (danios/barbs) and I can't even count the number of shrimps who have survived in the year since we upgraded to a 125. 

I appreciate your advice! I always have in the back of my mind that I have to be more careful in this 40 gallon breeder tank because the turtle is more forgiving about tank parameters. 

[itsfoxtail]

My first and main question would be: what fish are you planning to keep?

Just from my experience:

-You should absolutely re-mineralize your water, in my opinion, even if it's sparingly. Depending on what fish you're wanting to keep it will matter more or less. For example my rams and apistos love it when I do the occasional water change of pure RODI and tank the TDS, so they care a little less. Other fish such as guppies and cichlids, not so much, so they care a little more. I don't doubt they could live in such water, they just wouldn't be thriving. It's really your plants that are going to care about the re-mineralizing the most. I've had good luck with Seachem Equilibrium for fish and SaltyShrimp for shrimp. However, I've quite literally sort of stopped using Equilibrium in lieu of diluting my tap water. The tap water gives just enough minerals/nutrients to the RO water to create a healthy environment for the more delicate fish I have, as well as enough nutrients for the plants I keep with them!

-There isn't what I'd say is a SIGNIFICANT difference between RO and RODI. De-ionization basically is just a catch-all that sifts out what little is possibly left after reverse osmosis. After my water goes through the RO stage the TDS is right around like... 10 I want to say? (It's been a while since I checked). But once it goes through the DI stage it's right at 0. Those last few TDS in my opinion don't matter that much for freshwater. I use RODI water for both my salt and fresh tanks simply because I have it hooked up to go through both, but I'd feel confident using just RO water as a base for my fresh tanks. Most likely those last few TDS are just some type of minerals that the plants will suck up anyway (lol). RO water might have a slightly higher PH than RODI water because of this, but in my experience it's so small that it's literally undetectable in the testing kits.

-Does your RO filter have a carbon pre-filter? If so, no need to worry about chloramines. Also no need to worry with RODI as 0 TDS is a surefire way to tell there are no chloramines in the water. I suppose there could be a chance there are some if your RO doesn't have a carbon pre-filter, but I feel like the chances would be low. If you're worried about this you could always do a little testing and see!

I'm sure others on here will have some more awesome info and input but this is just what I've come to learn over the last couple years using RO/DI!

 

[JJenna]

On 11/6/2022 at 9:12 PM, itsfoxtail said:

Does your RO filter have a carbon pre-filter? If so, no need to worry about chloramines. Also no need to worry with RODI as 0 TDS is a surefire way to tell there are no chloramines in the water. I suppose there could be a chance there are some if your RO doesn't have a carbon pre-filter, but I feel like the chances would be low. If you're worried about this you could always do a little testing and see!

Great question! Going to look into that, appreciate the feedback.