# High TDS



## Fishguy04 (Feb 19, 2013)

I just purchased a TDS meter because I had some of my RCS dying every few days. I took a reading and it's at 920ppm, I took my tap water reading and it's at 180ppm. Why is my TDS higher in my tank than what comes out of my tap. Please any suggestions, thank you.


----------



## darkangel66n (May 15, 2013)

It is a build up of biological metabolites. Water changes with RO water dripped in slowly to bring it down.


----------



## Fishguy04 (Feb 19, 2013)

darkangel66n said:


> It is a build up of biological metabolites. Water changes with RO water dripped in slowly to bring it down.


I have an RO maker coming tomorrow, would there be a reason it goes so high when my tap water is so low?


----------



## darkangel66n (May 15, 2013)

Yes. Metabolites build up in the water between water changes. They are building up faster then you are removing them. Do you have fish in the tank as well? Do you have something in the tank that is slowly dissolving? Shells, carbonate rocks or coral? When you get your TDS down you will still need to use RO water but you must remineralize it. Somewhere between 100 and 200 is optimal.


----------



## Fishguy04 (Feb 19, 2013)

darkangel66n said:


> Yes. Metabolites build up in the water between water changes. They are building up faster then you are removing them. Do you have fish in the tank as well? Do you have something in the tank that is slowly dissolving? Shells, carbonate rocks or coral? When you get your TDS down you will still need to use RO water but you must remineralize it. Somewhere between 100 and 200 is optimal.


There are no fish, just snails and shrimp. I have some rocks in there but no coral. As for shells, I pull them out when they die, but I've had an infestation of these little snails that keep reproducing could they be causing it? I've also noticed they seem to be dying while they're moulting


----------



## darkangel66n (May 15, 2013)

They are dying when they molt because your TDS is way to high.


----------



## Fishguy04 (Feb 19, 2013)

darkangel66n said:


> They are dying when they molt because your TDS is way to high.


Thanks for the help. My RO maker came today I'd like some help on lowering my TDS. My current TDS is at 900ppm and I want to get it down to 200ppm, how much water should I be replacing each day so it's safe for the shrimp. It's a 20 gallon tank


----------



## darkangel66n (May 15, 2013)

No more then 10*/* and use an airline to slowly syphon the new water in. You will also need something to re mineralize the RO water to whatever reading you want.


----------



## Fishguy04 (Feb 19, 2013)

darkangel66n said:


> No more then 10*/* and use an airline to slowly syphon the new water in. You will also need something to re mineralize the RO water to whatever reading you want.


Should I start to re mineralize the RO right away, or wait for it to get close to what I want it to be then start


----------



## darkangel66n (May 15, 2013)

I would start right away. It will take longer but your shrimp will have more time to adjust.


----------



## aniroc (Aug 23, 2012)

I would not use a TDS meter to measure hardness in the tank's water.
TDS meter measure conductivity (water's ability to conduct an electrical current) and reflect the concentration of dissolved ions: sodium, calcium, chloride, sulfate, bicarbonates or any acids.
Hard water has a high conductivity but high conductivity does not mean hard water. Furthermore, glucose is a solid and it dissolves, it contributes to osmolarity, however, a TDS meter will not detect it because it is not ionized, thus does not conduct electricity.


----------



## Fishfur (Mar 4, 2012)

I am curious, did you do much in the way of WC on this tank, or mainly top it up ? 

I ask because repeatedly topping up without regular WCs in between will cause TDS to rise also, because each top up adds more hard water minerals, without water changes to dilute them.


----------



## Fishguy04 (Feb 19, 2013)

aniroc said:


> I would not use a TDS meter to measure hardness in the tank's water.
> TDS meter measure conductivity (water's ability to conduct an electrical current) and reflect the concentration of dissolved ions: sodium, calcium, chloride, sulfate, bicarbonates or any acids.
> Hard water has a high conductivity but high conductivity does not mean hard water. Furthermore, glucose is a solid and it dissolves, it contributes to osmolarity, however, a TDS meter will not detect it because it is not ionized, thus does not conduct electricity.


I've also been testing kh and gh, my gh is at 400ppm and my kh is around 150ppm. I'm using ro water now to bring down the TDS and I'm around 550ppm. I didn't think it would take this long


----------



## Fishguy04 (Feb 19, 2013)

Fishfur said:


> I am curious, did you do much in the way of WC on this tank, or mainly top it up ?
> 
> I ask because repeatedly topping up without regular WCs in between will cause TDS to rise also, because each top up adds more hard water minerals, without water changes to dilute them.


I was doing weekly WCs and top ups in between.


----------

