Lowering TDS

[Chiquarius]

Hello,

I’ve been attempting to lower TDS in my 10 gallon aquarium for a while. I’m trying to shift the parameters for Crystal shrimp and get down to about 120 ppm. Currently it’s at 180 ppm. I scoop out a gallon at a time and then pour in a gallon of rain water (approx 20 ppm TDS). After I’ve done this twice across the day, I read TDS and it’s still 180 ppm. I did the same thing yesterday and it remained the same. I’d expect 149-160 Now mathematically speaking. 

Ive got a canister filter going with medium and rinsed Akadama.

Any insight into why TDS won’t go down?

Also, I haven’t been remineralizing because I thought this would raise TDS. It has (hopefully enough) Aqueon shrimp essentials and Wellborne GH bee mineral comprising that TDS.

Thanks.

[sdlTBfanUK]

I don't understand how you are getting the same readings, with 2 gallon waterchange your math is right and it should drop to about 150 if the water you are adding is only TDS 20.

Are you sure your TDS meter is working, test it on tap water?  You haven't clicked the hold button have you? Move the TDS meter through the water rather than just dipping it?

When you have added the new water direct to the tank (?) you should mix it before testing!

It sounds like what you are doing is right and it isn't therefore possible that the TDS stays the same that I can see!

Simon

[Chiquarius]

Thanks Simon.

It is a cheap reader so perhaps that is the issue. I click the hold to shift modes to make sure it is on ppm and not mu (whatever that reads).

Perhaps it takes some time for the water to blend and find equilibrium and I should test the next day. Also, I just dip the tip. Maybe I should wave it around like you suggested.

I also have a gallon flowing through the canister filter, so that changes my math. I also have little bits of cuttlebone for the snails, maybe they are dissolving and raising TDS while I am trying to lose it.

Lastly, do you think Akadama in ‘buffering’ the water could be leaching minerals into TDS? Forgive my lack of chemistry knowledge here.

 

 

[jayc]

IF the TDS meter is working properly, than you have something in the tank that is replacing the Dissolved Solids as you add new water. 

The Akadama substrate can/will add to TDS measurement as it releases minerals. 

That cuttlefish bone will as well. 

A dirty canister filter media will add to TDS as well. 

All I can suggest is to try another gallon water change. A cheap TDS meter might not have a sensitive probe to detect enough of a change.