# Low GH but High TDS?



## Simplicity (Sep 29, 2011)

Hi All,

I have set up a 45Gal CRS/TB tank with ADA Amazonia + Africana. It is running a UGF to Cannister and sponge filters. It will be for my TBs/CRS

Params are 0/0/10-20, ph < 6.0, kh 0, gh 2-3, TDS 190ppm!! (close 2-month cycle) USING RO WATER! NO FERTS ONLY MY MOSSES!

I have been trying to raise gH to 4-6 in my large tank but all I manage to do is BOOST MY TDS! Used a mix of Mosura Mineral Plus Ultra and Fluval Shrimp Mineralize. 

The more I dose the higher my TDS and my gH barley moves!!! 

Can my carbon pad in my Eheim be removing gH?? HERE IS THE KICKER!!!

My existing CRS/TB tank has 130ppm TDS and 4GH using the same products and RO water!! what gives!?? What is absorbing my gH!?


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## jczernia (Apr 16, 2010)

How long have you been cycling this tank?I had the same thing happened to my tank while cycling with new amazonia


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## Simplicity (Sep 29, 2011)

-7 weeks


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## Sugardaddy1979 (Jan 16, 2012)

I think Amazonia can strip gh right?


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## Simplicity (Sep 29, 2011)

I dont understand how can ADA New Amazonia strip gH? My other tank doesnt have any issues with the old ADA Amazonia II, it is close to 2 years now... 

What am I suppose to do!?? I cant put in TBs with 200ppm and 3gh ....


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## randyl (Feb 1, 2012)

These substrates do strip out GH when new. Most people don't notice it as much because they don't use a lot of it. IIRC, you use a lot of substrate in a big tank, it will be okay, just will take a bit longer.


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## mordalphus (Jun 23, 2010)

You should not have carbon in your filter. 

The tds is most likely nitrate build up from your cycling.


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## Simplicity (Sep 29, 2011)

mordalphus said:


> You should not have carbon in your filter.
> 
> The tds is most likely nitrate build up from your cycling.


I will do afew MASSIVE W/Cs tonight and remove the carbon. Hope for the best ........ (no livestock in it)

Get params down to 120-150ppm .... then will dose some Mosura Mineral Plus to boost to 4gH........... I hope..

Does this sound like a good plan??


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## sayurasem (Jun 17, 2011)

Are you mixing mosura mineral with fluval mineral for your water?


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## Simplicity (Sep 29, 2011)

sayurasem said:


> Are you mixing mosura mineral with fluval mineral for your water?


Yes :s is that bad? I am mixing re-mineralization products.... :S

I also have about 30 Lbs of Aqua Soil and like 45L tank..


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## mordalphus (Jun 23, 2010)

Just take all of the water out of the aquarium, then refill with RO and remineralize until your GH is 5.

Doesnt matter what your tds is at that point, because that will be your clean water reading.


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## zdnet (Aug 13, 2010)

Simplicity said:


> Hi All,
> 
> I have set up a 45Gal CRS/TB tank with ADA Amazonia + Africana. It is running a UGF to Cannister and sponge filters. It will be for my TBs/CRS
> 
> ...


To keep TDS within control, you need to know the purity (or impurity) of what you are dosing. That will allow you to determine in advance how much "pollutants" you will be adding as you dose to maintain the required GH level.

To determine purity, get a reading of your RO water's TDS (the GH should be zero), dose Mosura Mineral Plus Ultra or Fluval Shrimp Mineral, then get a reading of the resulting TDS and GH. Purity is high when the ppm increase of TDS equals (or is very close) to that of GH.


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## Simplicity (Sep 29, 2011)

mordalphus said:


> Just take all of the water out of the aquarium, then refill with RO and remineralize until your GH is 5.
> 
> Doesnt matter what your tds is at that point, because that will be your clean water reading.


UGH.... I am preparing the 50G of RO water. Guessing its gonna take me a week to get enough RO water


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## mordalphus (Jun 23, 2010)

You could always buy the RO from the store if you don't want to wait.


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## Simplicity (Sep 29, 2011)

So I did a 75% water change with PURE RO (5ppm TDS). (sucked water from all over the tank)

My TDS went down to around 60ppm total. 

I removed my carbon from my Eheim aswell. I also added a Mineral Rock and sprinked some Mosura Mineral Powder (forgot name)

I dosed a someMosura Mineral Plus and bumped my TDS to 140-150ppm. Re-tested my gH and it is barely 3gh .....its still the same!! (I mean it might be 2gh or 3gH hard to tell)

Did a small test...
15L RO + Remineralize to 60ppm = 5gh! Why does my gH drop to 2-3 with 150ppm in the tank!!! 

VERY STRANGE! This my only issue before introducing my CRS. Anymore help would be great!


My next step is to dose more Mosura Mineral Plus Ultra and aim for 170ppm TDS and retest.. might hit 4gH.... which would be great


A theory someone on another forum said ADA Africana could be the cause for absorbing gH


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## mordalphus (Jun 23, 2010)

If it was your soil the tds would drop too. 

Some mineral products are just higher tds than others. Either way, 5 gh would never be 60 tds, the least it could be is 90 tds. Each degree of hardness is 17.9 ppm. 

Also you said you added a mineral stone and mineral powder, which both raise the tds but not the GH. 

Or maybe something is wrong with your GH test.


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## Simplicity (Sep 29, 2011)

mordalphus said:


> If it was your soil the tds would drop too.
> 
> Some mineral products are just higher tds than others. Either way, 5 gh would never be 60 tds, the least it could be is 90 tds. Each degree of hardness is 17.9 ppm.
> 
> ...


or my tds pen is broken :s


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## mordalphus (Jun 23, 2010)

Could be! Many possibilities, but I'm thinking it's a testing error, and not a big issue.


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## zdnet (Aug 13, 2010)

> tested purity of my ro
> 
> RO = 5-10ppm
> gh = 0
> ...


Starting with the RO water of 5-10 ppm, you remineralized to 60 ppm. That means the remineralization had added no more than 55 ppm.

Even with the most efficient GH booster, 55 ppm could not be more than 3 GH (1 GH is 17.9 ppm). And yet your GH result showed 4-5 GH. The GH result is incorrect.

Because your GH result for the above test is incorrect, the one for your tank water is likely incorrect as well.

Since you are trying to raise GH to a certain level, a correct GH result is very important. I would try the Nutrafin GH test kit - much easier to spot color change.




> or my tds pen is broken


Your TDS pen showed that your RO water was between 5-10 ppm, it is not that far off. More likely the problem is with your GH test kit.


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