Freshwater RODI TDS

[bry1105]

I have a community freshwater aquarium. I use RO/DI water and add Kent RO Right for the trace elements freshwater fish need to have put back in. My RO/DI system has a dual inline TDS meter so I know my product water has a TDS of 0ppm. Is there a need for me to test the TDS of the water in the aquarium? The Kent RO Right bottle recommends a TDS of 160-220 for freshwater. Should I test the water in the aquarium so that I know how much RO Right to add (until I go from 0 to about 200)?

 

[OasisKeeper]

You could do that. It would be nice to know what GH/KH Kent thinks will result from those readings, since I would be more interested to know those values. The problem with TDS readings is that they include most everything that conducts, including things like sodium ions from the salts. Its not a great indicator of things that might effect the fish.

TDS certain is valuable for knowing you have really ion free water to start with. I'd be happier with more detail from an operating tank.

OTOH, back in my reef days, I found the best test tool of all was my nose.

 

[bry1105]

So if at every water change I am starting with 100% RODI water (0ppm TDS) how do I know how much Kent RO Right to add? What should I be testing so that I know the water will be safe for my aquarium?

I know this is kind of a dumb question, but I want to hear someone say it so that I feel better: trace elements added to RODI water for freshwater aquariums (such as Kent RO Right) only add good stuff right? I mean, Im filtering my tap to get rid of all the crap (including phosphates & silicates that gave me terrible diatoms). What does the RODI filter out and what does the trace elements add back in?

 

[OasisKeeper]

So if at every water change I am starting with 100% RODI water (0ppm TDS) how do I know how much Kent RO Right to add? How do I know that the water will be safe for my aquarium?

I know this is kind of a dumb question, but I want to hear someone say it so that I feel better: trace elements added to RODI water for freshwater aquariums (such as Kent RO Right) only add good stuff right? I mean, Im filtering my tap to get rid of all the crap (including phosphates & silicates that gave me terrible diatoms). What does the RODI filter out and what does the trace elemnts add back in?

Not dumb at all. You are trusting Kent to tell you. No reason not to believe them. RODI takes nearly everything out. All that is left is little H's and O's and they seem to get along pretty well together.

I have used Seachems similar product (the name escapes me). Don't Worry! Be Happy! Runs some GH KH tests if you like (Trust but verify?). Mostly, watch the fish.. they will whisper to you of problems.

 

[bry1105]

Seachem makes Equilibrium but I think it's meant for planted tanks.

If Im understanding you correctly, you're saying I should trust Kent as to how much to use, but still test the GH KH of the water in my aquarium just to make sure.

 

[OasisKeeper]

Yah, I think I would. For one thing, I would want to be sure I had enough KH to keep the pH swings down and enough GH for the type of fish I was keeping. If its off, you can adjust the amount you are using in the water changes.

 

[bry1105]

...I would want to be sure I had enough KH to keep the pH swings down...

Yeah, I learned that the hard way. Lost a couple fish.

Thanks! You've been a lot of help.