TDS

[Wilfred Yang]

Why planted shrimp tank TDS reading keep dropping

 

[jayc]

1 hour ago, Wilfred Yang said:

Why planted shrimp tank TDS reading keep dropping

Need more info. What are you doing with the tank during water changes?

Are you using RO water without remineralising it with Calcium & Magnesium sulphate?

[Zoidburg]

What substrate? Pictures of tank? Need more info.

[jayc]

I have heard of TDS rising.

 But never have I heard of TDS dropping. Everytime you add something to the tank, everytime a fish or shrimp produces waste - TDS will rise. 

TDS dropping by itself doesn't make sense. That means dissolved solids are just ... vanishing. And that cannot happen even with evaporation.

[Zoidburg]

If it's a heavily planted tank, it's my understanding that TDS can drop as the plants use up the nutrients in the water source....

 

I don't have heavily planted tanks to test this out...

[Wilfred Yang]

Need more info. What are you doing with the tank during water changes?
Are you using RO water without remineralising it with Calcium & Magnesium sulphate?

Sorry for the late reply. Been out of town for the last few days. Here is a picture of my tank.

Tank size 32litre
PH 7.0
GH 3~4 dkh
KH 0~1 dkh
TDS of my Tap water 80ppm





Sent from my iPhone using Tapatalk

[Zoidburg]

What substrate is that?

 

You probably want to raise GH up around 7 for the shrimp.

[jayc]

I (still) don't know why TDS would be dropping in your tank. Nothing looks unusual there.

What is in your filter media?

Are you using carbon/charcoal by any chance?

If you are, that could be a reason.

 

But as Zoidburg said, raise your GH by using a remineraliser like Salty Shrimp GH+.  Or mix your own Calcium sulphate & magnesium sulphate.

Edited November 13, 2018 by jayc

[Wilfred Yang]

I (still) don't know why TDS would be dropping in your tank. Nothing looks unusual there.
What is in your filter media?
Are you using carbon/charcoal by any chance?
If you are, that could be a reason.
 
But as Zoidburg said, raise your GH by using a remineraliser like Salty Shrimp GH+.  Or mix your own Calcium sulphate & magnesium sulphate.

Had gradually increase my GH to 6 dkh, as suggested.TDS reading increase to 135ppm, is this normal?
No do not use carbon or charcoal.
Should I also increase my KH, but my PH is stable at 6.9
As for the substrate, it a Japanese brand mend for plant and shrimp.



Sent from my iPhone using Tapatalk

[jayc]

45 minutes ago, Wilfred Yang said:

increase my GH to 6 dkh, as suggested.TDS reading increase to 135ppm, is this normal?

Yes, that's normal. What did you use to raise GH?

Keep it at that level for a while. So match your water changes to those parameters.

 

[Zoidburg]

1 GH = ~18ppm minimum

So 6 GH would be about 108, not counting other things that raise TDS.

Remineralizers vary. Some are "clean" (i.e. 1 GH is close to 18-20ppm) where-as others are "dirty" (1 GH could be 25-30ppm+)

 

The substrate *might* be pulling GH and KH from the water column, which "charges" the substrate for plant growth, or rather, the soils ability to retain nutrients for plants. To quote Wikipedia...

Quote

Cation-exchange capacity (CEC) is a measure of how many cations can be retained on soil particle surfaces.

 

If the substrate is also meant to lower the pH of the water, then you do not want any KH in the water as that will increase the likelihood of unstable water parameters.

If the soil does not buffer the pH down, then you do want to raise the KH to around 2-3.