# Blackwater and TDS



## Ted (26 Apr 2014)

Hi - I'm working on a 40L blackwater tank to breed my betta albimarginatas. We're using RO water but the TDS is still quite high (~400). This is due to the presence of organic solid decomposition (from catappa leaves and driftwood). I understand that these fish appreciate decomposed leaf litter and driftwood. They also require soft water. 

I know a good many of you are experienced blackwater and particularly betta aquarists: My questions are-
(1) Are all contributants to TDS equal? Are certain solids like driftwood decomposition tolerable where others aren't?
(2) If I want fertile eggs, do I need to clear all the organic solids from the tank and abstain from leaf litter,driftwood etc?

Many thanks!


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## bogwood (27 Apr 2014)

HI.
I only have experience with Bee shrimps.
However i use RO, my tanks have Plenty of wood in, the bottom is covered with catappa leaves, oak bark, pine cones, etc.
I dont remove them,and add far more than recommended.
Carbon is used at times to manage the tannin strength in the water.
I have no difficulty holding a TDS of 130, even with small amounts of ferts added.
cheers


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## Edvet (27 Apr 2014)

In my betta tank i use RO water, leaves and once a week 10% wc with water from a bucket with peat (this is regular tap water), TDS is app 120.


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## dw1305 (27 Apr 2014)

Hi all, 





> We're using RO water but the TDS is still quite high (~400). This is due to the presence of organic solid decomposition (from catappa leaves and driftwood).


 I'm pretty sure there is some other source of TDS in the tank, the reason I say that is that TDS meters don't actually measure TDS (and the tannic compounds etc would contribute to the TDS), they measure conductivity, and you get very few ions from dead leaves or dead wood.

You should be able to get down to ~50 ppm TDS with heavily tinted RO.





> (1) Are all contributants to TDS equal? Are certain solids like driftwood decomposition tolerable where others aren't?


 If you really were measuring TDS (which you can only do by evaporating a known volume of water to dryness and measuring the residue) then the TDS resulting from humic and tannic compounds is different from TDS caused by ions such as calcium (Ca++) etc.





> (2) If I want fertile eggs, do I need to clear all the organic solids from the tank and abstain from leaf litter,driftwood etc?


 No you don't , it is really the more the better, humic compounds serve all sorts of useful purpose in tanks such as complexing heavy metal ions and acting as anti-microbial compounds. In black water habitats there is a huge amount of leaf litter. 

Have a look at the DOC section from the ever erudite Skeptical Aquarist:
<http://www.skepticalaquarist.com/humic-acids>
<http://www.skepticalaquarist.com/leaf-litter>
<http://www.skepticalaquarist.com/chelation>

cheers Darrel


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## ourmanflint (28 Apr 2014)

Hi Darrel,
I would normally have agreed with you but I think Catappa do contribute a huge amount of ions to tank when dissolved.
Theres a post here that explains it.
http://www.parosphromenus-project.org/en/forum/12-Methods/1487-walnut-leaves.html?start=12

Cheers


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## dw1305 (28 Apr 2014)

Hi all, 





ourmanflint said:


> I would normally have agreed with you but I think Catappa do contribute a huge amount of ions to tank when dissolved.Theres a post here that explains it. <http://www.parosphromenus-project.org/en/forum/12-Methods/1487-walnut-leaves.html?start=12>


 He doesn't understand pH.

It is true that acids contribute to the conductivity (by adding the hydronium ion (H3O+), but you can think of it as adding H+ ions), but after that it all goes skew and the graph he produced isn't relevant to aquarium usage  





> _I measured different humins in oversaturated concentration_


 is the problem. He has produced a very concentrated extract of various humic and tannin producing substances and then measured the conductivity of these and extrapolated that to the tank situation.

If you went back to the tea analogy (from <http://www.ukaps.org/forum/threads/why-do-we-aim-for-30-ppm-co2.32428/page-3#post-345645>), he is saying that there is no difference to the tea whether you add one tea bag to a teapot full of water, or fill the cup up with tea bags, add the water, let it sit for a long time and then squeeze the fluid out of the saturated tea bags.   He is saying they are both the same, but they obviously aren't.

Anything you add to RO water will increase the conductivity, but you would have to add a huge amount of weak acids to get to 400 microS. 

The other bit of the thread is more relevant 





> Ibok, Malaysia, 22microS, pH 5.3.


 cheers Darrel


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## Edvet (28 Apr 2014)

I have to correct, it's 90 microsiemens actually, in my tank.


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## ourmanflint (28 Apr 2014)

dw1305 said:


> Hi all,  He doesn't understand pH.
> 
> It is true that acids contribute to the conductivity (by adding the hydronium ion (H3O+), but you can think of it as adding H+ ions), but after that it all goes skew and the graph he produced isn't relevant to aquarium usage   is the problem. He has produced a very concentrated extract of various humic and tannin producing substances and then measured the conductivity of these and extrapolated that to the tank situation.
> 
> ...



I agree his methodology has problems, but in relative terms using CatAppa leaves would raise conductivity by a larger amount than just peat for example


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## dw1305 (28 Apr 2014)

Hi all, 





ourmanflint said:


> I agree his methodology has problems, but in relative terms using Catappa leaves would raise conductivity by a larger amount than just peat for example


 Leaves will raise conductivity, but peat is a slightly different argument from most other humic substances, mainly because it has both a large "cation ion exchange", as well as the ability to chelate, complex or sequester cations.

I've never used _Terminalia catappa_ leaves, but I know that a handful of dead Oak or Magnolia leaves in 60 litres of rain-water has little or no effect on conductivity (or pH).

I couldn't find any pictures for black-water streams in Borneo, but there are pictures from S. American "black water" streams on Tom C's web site <"Collecting in the Peruvian Amazon - Río Tahuayo and the Río Tamshiyacu drainages">

Also have a look at <"Brian's Tropical - _Betta albimarginata"_> and Colin Dunlop's <"All the leaves are brown">.

cheers Darrel


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## ourmanflint (28 Apr 2014)

Ive got a big bag of terminalia leaves coming over from Thailand this week so I can send you a few to try if you want Darrel?


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## dw1305 (29 Apr 2014)

Hi all, 





ourmanflint said:


> Ive got a big bag of terminalia leaves coming over from Thailand this week so I can send you a few to try if you want Darrel


 Could do, I've got access to DI water and lab. pH & conductivity meters, or if you've got a conductivity meter? I can send you a bag of assorted humic substances (different leaves, peat, alder cones etc) and you can have a play with them.

I've always meant to do some quantitative tests, but I've never got round to it, details here <http://www.apistogramma.com/forum/threads/what-dead-leaves-used-in-tanks.12777/#post-70150>

cheers Darrel


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## BigTom (29 Apr 2014)

400 TDS (well, 800 microsiemens I guess) does seem an awful lot just from leaves. I recently played around with making some concentrated blackwater extract by boiling a large pan brim-full with a mix of beech and terminilia leaves in RO water for several hours, steeping overnight and then reducing down to about a pint, and that produced an extract that was 900 microsiemens and pH 4.5.

PS, I believe that albis are relatively tolerant of water conditions, so as long as your water is relatively soft and acidic I think you'll be OK.


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## sciencefiction (30 Apr 2014)

I add oak leaves to a tank enough to fully cover a 30G tank at once and to be honest haven't noticed much TDS difference. Once they start melting/eaten by shrimp, I add more without removing the old and like that for the last year, not much TDS rise. If there is, it's slow and the water changes are taking care of it.


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## Edvet (1 May 2014)

dw1305 said:


> I couldn't find any pictures for black-water streams in Borneo


 
Some finds Darrel:
http://borneoechostreams.blogspot.de/
https://www.flickr.com/photos/sarawaklens/sets/
http://www.aquaticquotient.com/forum/showthread.php/59872-Visit-the-Cryptocoryne-habitats-in-Sarawak


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