Who Gives A Fish Forums

Been thinking about switching to RO water for my 55 gallon planted tank. Heard it's better for sensitive fish, but I'm worried about remineralizing it right. Anyone got tips or brands they swear by?

I've been using RO for my Discus for about a year now. Started with Seachem Equilibrium but switched to Salty Shrimp GH/KH+. Way easier to dose, and my fish seem happier. Just gotta test the water a lot at first.

RO water is a game changer if you're dealing with hard tap water. I use a 5-stage RO/DI unit from Bulk Reef Supply. Pair it with a TDS meter to monitor purity. Remineralize with a 3:1 ratio of calcium chloride and magnesium sulfate for stability.

muddywave wrote: ↑Thu Jul 24, 2025 1:44 pm I've been using RO for my Discus for about a year now. Started with Seachem Equilibrium but switched to Salty Shrimp GH/KH+. Way easier to dose, and my fish seem happier. Just gotta test the water a lot at first.

Thanks for the rec. How often do you test when you're first starting out?

I tested daily for the first week, then tapered off to twice a week once I got the hang of it. It's a bit of a hassle, but worth it to avoid shocking the fish. My TDS stays around 150 now, and the Discus are thriving.

Consistency is key with RO. I'd also recommend a drip acclimation method for water changes. Sudden shifts in TDS can stress fish, even if the params are technically safe. A 1-2 hour drip works wonders for sensitive species.

creekrow wrote: ↑Thu Jul 24, 2025 4:03 pm Consistency is key with RO. I'd also recommend a drip acclimation method for water changes. Sudden shifts in TDS can stress fish, even if the params are technically safe. A 1-2 hour drip works wonders for sensitive species.

Gotcha. I'll look into a drip system. Any tips on keeping the TDS stable between changes?

I mix my RO water in a brute trash can with the minerals a day before water changes. Let it sit with a pump to circulate. That way, everything's evenly mixed and the temp matches the tank. No surprises.

Pre-mixing is solid advice. I also keep a log of TDS and GH/KH levels after each water change. Over time, you'll see patterns and can adjust dosing before issues arise. It's extra work, but my Cardinals and Rams have never looked better.