Lake Tanganyika Species • What is your water recipe

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What is your water recipe

Postby Ptyochromis » Sat Mar 24, 2012 9:03 pm

What is your water recipe? My water out of the tap is quite hard as there are local phosphate mines, I add 1TBSP of Instant Ocean salt mix per every 5g I add. I read http://www.thekrib.com/Plants/CO2/rift.html from the krib.com discussing Rift lake water. They also discuss the inaccuracy of testing carbonate hardness as, and I quote:

"Hardness is defined as the concentration of multivalent metallic cations
in solution. This DOES NOT include Na+, since it's NOT multivalent).
Hardness is composed of carbonate harness and non-carbonate hardness. If
your kit tests for carbonate hardness ONLY, you won't be getting a true
reading of TOTAL hardness, which in Tanganyika is important. Check this.
CaCO3, for example, would contribute to carbonate hardness, but CaCL2
would not, since it has no carbonate. The term "carbonate" hardness can
be somewhat misleading. Remember--MULTIVALENT only."

Got me thinking, What do you guys(and girls) do to your water? And would you mind sharing what the hardness levels are out of the tap and what you add to the water?
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Postby 24Tropheus » Sat Mar 24, 2012 9:52 pm

My tap water KH measures 14 deg my GH measures 20 deg conductivity measures 600.
Tank water pH stays between 8.2 and 8.6 (Though the mains tap water when fresh measures much lower than this but comes to the tank water value when aerated for a few hours and warmed up ready for use)
I do not need to add anything. (Other than a chloramine remover Seachem Safe as its cheapest per gallon treated). If anything I should dilute with RO and add a bit of KCl and K2CO3 (potassium carbonate) to bring down the GH and increase the KH while keeping the conductivity but I do not think my fish would notice the difference.

I do worry about folk adding sea salt to thier water without first checking it is needed or wanted.
Lake has a conductivity of just over 600 so I think best not go above this, as the lake is getting more concentrated and the fish are still adapting to this.
Tanks 180, empty revamping 100,65,60g Tropheus/tang communities 75g revamping. 29gx3 shelly communities, 29g Trigs breeding. 20gx2 shelly tanks. BCA member 207. Try it you might like it.
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Postby BillD » Sat Mar 24, 2012 10:40 pm

Lots of people around here keep tangs in straight tap water around 7.4 to 7.6 pH, and medium hard, from Lake Ontario.
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Postby GTZ » Sat Mar 24, 2012 11:33 pm

BillD wrote:Lots of people around here keep tangs in straight tap water around 7.4 to 7.6 pH, and medium hard, from Lake Ontario.

I'm one of those people.
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Postby darkstar22 » Sun Mar 25, 2012 12:40 am

I use RO/DI water and then add Seachem Tanganyikan buffer and Cichlid Salts according to the package instructions. This works for me. I have an RO/DI unit for my Reef Tank, and since I need it for that I just utilize it for my Tang Tank! It works out well for me. My Cyps breed on a regular basis, and so do my Xeno's.
From what I read it is not necessary, but why mess with what works for me!
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Postby triscuit » Sun Mar 25, 2012 7:45 am

I use baking soda and epsom salt to buffer and harden my tap water. It's cheap and simple, and my fish don't mind. As far as the krib.com quote above, it's a bit misleading. Not wrong, but kh and gh function independently. I think the author is confusing hardness with alkalinity, which is beyond what most hobbyists can measure at home, let alone what they care (or need to care) about.
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Postby BillD » Sun Mar 25, 2012 10:14 am

Alkalinity is of concern, in that your total alkalinity, will tell you your buffering capacity. If the TA is high enough your pH will not fluctuate. This only matters if you think pH has any importance. With swimming pools, baking soda is used as a buffer to maintain the correct TA, and thereby, the correct pH. The pH in a swimming pool should be between 7.4 and 7.6 because it approximates the pH of your eyes, and chlorine works more effectively in this range. In an aquarium, this of less importance in most cases, and certainly for those where the pH is above neutral and the conductivity is relatively high. this is probably the case of most tap waters, as municipalities attempt to maintain enough alkalinity to protect their infrastructure from corrosion. The extreme cases where low pH may be required, the conductivity will also be very low. We recently had a presentation on the Mazurunia river system (home of Mazurunia mazurunii cichlid), and the tributaries have a pH of 4.5 and no measurable conductivity. Fish from these waters might have difficulty acclimating to our mid hard water and 7.6 pH, but it won't be because of the pH, but rather because of the Total Dissolved Solids (TDS) in the tap water.
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Postby triscuit » Sun Mar 25, 2012 6:20 pm

The extreme cases where low pH may be required, the conductivity will also be very low.


Low pH is unrelated to the conductivity of a given water sample. Pure H2O in equilibrium with the atmosphere will be at pH 5.6, and have very low conductivity. Add organic acids, and your pH will drop and your conductivity will increase. Add a small amount of a strong base to pure water, and your pH will jump to that base's pKa, with very little change in conductivity.

Total alkalinity is a calculation, not a measurement. Buffering capacity can be measured, and in our rift tanks, is enough to tell us about pH stability.
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Postby BillD » Mon Mar 26, 2012 10:03 am

While low pH may be unrelated to conductivity specifically, they tend to go together. Black water of the type I mentioned above is extremely soft and acidic because of the organics that tint the water. Yet, the conductivity is unmeasurable even at 4.5 pH. Indeed, adding a strong base to pure water will cause a large jump, with little effect on conductivity because there is no buffering capacity and it doesn't take much to create a large change. I should have said that the conductivity will likely be low, with low pH.
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Postby triscuit » Mon Mar 26, 2012 1:41 pm

I appreciate your contributions, but I think our use of some of the terms may be limiting our understanding. :)

The organics that you are talking about are often uncharged species- if they are not ionic, they won't contribute to acidity or conductivity. The organic acids I'm talking about are charged species (dissolved organic matter typically has an average charge of -4) and they are weak acids (do not quickly dissociate), so they do contribute to conductivity and only weakly contribute to acidity.

Blackwater river systems are often dilute (low conductance), but that has little to do with DOM content. There are many more systems that are anthropogenically acidified (acid rain, mine tailings, etc) that are more highly conductive do to leaching of base cations into the surface water. Naturally acidic systems with longer water residence times, and perhaps larger watersheds, can also have high uS/cm2 values and low pH.

So, no- low pH and low conductivity do not "tend to go together"

And, no-
adding a strong base to pure water will cause a large jump, with little effect on conductivity because there is no buffering capacity
- that is wrong. Buffering capacity is a measurement of bicarbonate ions, which contribute to conductivity. Adding a strong base, either to pure water, or water with a significant buffering capacity will have the exact effect on conductivity. More ions -> Higher conductivity.
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Postby 24Tropheus » Tue Mar 27, 2012 12:25 pm

And, no-
adding a strong base to pure water will cause a large jump, with little effect on conductivity because there is no buffering capacity
- that is wrong. Buffering capacity is a measurement of bicarbonate ions, which contribute to conductivity. Adding a strong base, either to pure water, or water with a significant buffering capacity will have the exact effect on conductivity. More ions -> Higher conductivity.

I think he ment a jump in pH. In which case yep?
Strong alkalis increasing pH a lot (esp without buffers (buffers being week acids combined with week alkalis)) (not just bicarbonates (sorry)) while not increasing the conductivity much.
I know per molicule they increase the conductivity just as much as any other ion but all these things are relative. :wink:
The statement then becomes correct though the reason following it is false?
Tanks 180, empty revamping 100,65,60g Tropheus/tang communities 75g revamping. 29gx3 shelly communities, 29g Trigs breeding. 20gx2 shelly tanks. BCA member 207. Try it you might like it.
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Postby triscuit » Tue Mar 27, 2012 1:25 pm

24Tropheus wrote:I think he ment a jump in pH. In which case yep?

Strong alkalis increasing pH a lot (esp without buffers (buffers being week acids combined with week alkalis)) (not just bicarbonates (sorry)) while not increasing the conductivity much.
I know per molicule they increase the conductivity just as much as any other ion but all these things are relative. :wink:
The statement then becomes correct though the reason following it is false?


:D I see what you mean. I'll try to explain more clearly...

So, yes, strong bases increase pH- how much of an increase depends on what else is in the water. My problem was with why the poster said conductivity doesn't increase much. Because we're discussing supposed linkages between pH and conductivity, the reasoning behind the statement is key to understanding buffering, equilibrium chemistry, and what the fish actually care about.

And buffering- that is only attributable to multiprotic acids... you can have a carbonate buffer, a phosphate buffer, or an acetate buffer, for example. For a Tang tank, we're really only talking about the bicarbonate buffering system. What you are thinking of is probably Acid Neutralizing Capacity (ANC), not buffering. :thumb:
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Postby Ptyochromis » Tue Mar 27, 2012 1:34 pm

triscuit wrote:For a Tang tank, we're really only talking about the bicarbonate buffering system. What you are thinking of is probably Acid Neutralizing Capacity (ANC), not buffering. :thumb:


Why are we only talking about carbonate buffering when the lake is low in carbonates?
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Postby triscuit » Tue Mar 27, 2012 2:59 pm

Good question!

Because the main source of buffering capacity for a home aquarium is bicarbonate. It's cheap, easy, reliable, and has the appropriate dissociation equilibrium to maintain pH where we want it.

Baking soda- NaHCO3 - sodium bicarbonate - alone will stabilize pH at 8.2
Soda ash- Na2CO3 - sodium carbonate - in combination with NaHCO3, pH can stabilize at 9.2

These are the main components of commercial rift lake buffers. There are other buffer systems that can be used, but they will have a larger effect on the nutrient balance. For example, a phosphate buffer will add phosphate to your tank...
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Postby 24Tropheus » Tue Mar 27, 2012 4:32 pm

Why would anyone want a pH of 9.2 when even the lake is only 8.66-9.06?
As I understand it lake pH is rising and the fish still struggling to adapt to this.
pH 8.2 more than high enough?
(Esp as most tank pollutants (nitrogen compounds) become more toxic with increased pH and filtration bacteria ever less efficient at above 8.2 -8.6 ish)
Last edited by 24Tropheus on Tue Mar 27, 2012 4:44 pm, edited 3 times in total.
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