A few questions about adjusting RO /DI water

[Jeapa]

I am new to the forum and I have a few questions about adjusting my water. I am not new to keeping discus, but when I had them before back in the mid nineties I never had to adjust my tap water.

My current water source has a nitrate reading of 15 ppm so I am using an RO filter. I added Seachem Replenish and this brought the gh up to 10, but the ph is still very low probably a little less then 6.0. Should I be worried about this ph level? I have never really had a ph this low before in all my years of fish keeping so I am not sure if the fish will just adjust, or if I would be better off raising it just a little. I really dislike having to add chemicals to the water if I can avoid it as I am a firm believer in stability being the most important over actual numbers. My concern is that the water may not have enough buffering capacity and the ph could drop even lower once I have fish and plants in the tank. If anyone has any pointers on a better system for adding the minerals back into the RO water I would love to hear it. I tested the reject water and it still had nitrates so I do not want to use it.

Thanks.

[TURQ64]

You may search here for more opinions, but many of use use either the RO waste water (reject) or tap to add minerals back instead of powdered additives...test as sample of each for tds in one gallon. Then it's simple math to determine what leevel you want to add back. Your Ph will probably rise with aeriation, but either way, stable ph is more important than some magical number...Gary

[Chad Hughes]

Welcome to the forum!

Here's my $.02 on your situation.

If your only issue with your tap water is the nitrate AND you intend on keeping a planted tank, just use your tap water. Your plants should readily consume your nitrates. I have kept planted tanks for years and I actuialy have to add nitrates to the tank to keep the plants healthy.

Another option that you have is Ion-exchange. Ion-exchange takes another substance, such as chloride, and trades places with nitrate. An ion exchange unit is filled with special resin beads that are charged with chloride. As water passes over the beads, the resin takes up nitrate in exchange for chloride. As more water passes over the resin, all the chloride is exchanged for nitrate. The resin is recharged by backwashing with sodium chloride solution.

Hope that helps!

[Jeapa]

Thanks for the tips. I experimented a little bit this morning and I think I have it figured out. One teaspoon of baking soda combined with 2 capfuls of the Seachem Replenish to my mixing barrel gave me 3 gh and 1 kh with a ph of 6.4. I like those numbers and it should be easy enough to keep things stable.

I like the idea of the plants being able to use the nitrate, but I have never started with a level that high right from the tap. Once my plants have established and are growing well I may try that. I already had the RODI unit so I will use it for now. Thanks for the welcome.