Pottasium Bicarbonate

calihawker

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Jan 7, 2008
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I asked this question on another forum but I'll ask it here as well.
How much potassium in ppm is added when using potassium bicarbonate to raise the hardness of water 4dKH?

Thanks!!

Steve
 

creighton

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Jun 18, 2007
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Depends on the waters initial hardness, how much you add, ect. I think you just take the percent K by mass of the Potassium Bicarbonate of what you added to get the mass of the K in grams. Then using the grams you can calculate ppm, which is just mg/L. You may want to verify this with someone else. Its been a while since I've taken chemistry.

Hope that helps a little
 

calihawker

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Jan 7, 2008
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Thanks Creighton. That sounds about right but my chemistry knowledge is very poor and I would like someone to verify. My water hardness is basically zero. I am going to start a 50 gallon a day water change routine on a 300 gallon heavily planted high light, high tech tank.
Steve
 

creighton

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Why have you decided to you Potassium Bicarbonate rather than Sodium Bicarbonate?
 

calihawker

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I know the age old debate that argues sodium dosen't harm a planted aquarium, and believe me I don't want to start it here but it still is debatable. I'd just rather not add something that you don't need when I can do the same thing with something you're adding anyway.

The real question I'd like to know is why people don't use potassium bicarbonate? Is it the availability or the price or both? If you had the choice and everything was equal would you use sodium or potassium?

I'd really like to hear Tom chime in on this if he's around.

Steve
 

VaughnH

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The current thinking seems to be settling on just using low KH water without trying to jack up the KH. Most plants do as well or better with low KH water. The buffering effect of KH can be useful, but isn't really a deal breaker.
 

calihawker

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Thanks Vaughn. My main concern is the ph swings once I establish the discus and when I say low kh, i'm talking like 12 ppm. Not that I can check it that low but that's what the water board says. Effectively zero carbonate hardness.

Steve
 

Tom Barr

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That's fine a tad less than 1 degree, no issue with that.
Discus come from places that have no KH.

Why is it an issue?

As long as the CO2 is stable and the same rate added, the CO2 concentration will be the same. You cannot measure CO2 via pH/KH, because the KH is zero, thus any ratio would be NA due to a zero reading.

But it's not needed for plants or fish.

Regards,
Tom Barr
 

calihawker

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The only thing I'm concerned with is ph swings, especially with a discus tank. If I can continue to use the controller to inject C02 and maintain constant ph, then I'd be happy to have one less thing to dose.

Steve
 

Tom Barr

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What do think occurs in natural systems?

Many lakes and backwaters that have plants go from 6 to 8-9 even 10 every day.
This does not affect fish.

pH swings that involve salts, like adding/deleting sodium bicarbonate rapidly, that is what influences fish/shrimp etc

Not pH alone.

Once you realize this, you'll be okay.:cool:

CO2 is not a salt.
Think about CO2, it's in their blood and can be exchanged easily and rapidly.
What about HCO3?
Does KH evaporate? Can it degas?

Nope.

Regards,
Tom Barr
 

calihawker

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Thanks Tom. I really appreciate your comments and I'm gonna go in that direction. One more question though. Is using the ph controller the best way to automate c02? The way I have it programmed right now is to keep ph between 6.75 and 6.8 and shut off completely at night. I guess I should lower it to ~6.15 with a kh less than 1. What do you think?

Steve
 

VaughnH

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Rather than concerning yourself with pH, why not try to maintain a steady ppm of CO2 during the days? And, trying to make that ppm be about 30 ppm? You can use a drop checker, with 4 dKH distilled or deionized water in it, to do that. Then, if you make sure there is good water flow throughout the tank, such that leaves on all of the plants are swaying in the flow, you can probably eliminate CO2 as being a problem. The fish will continue to do well with the soft water, and if you don't go much above 30 ppm of CO2, they will do well with the CO2.
 

calihawker

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Well, the key word here is automation. I'm routinely out of town a couple weeks at a time. I've spent a lot of effort on my dosing and water change systems and they are now fully automated. I know that kh and ph are directly related to c02 levels and of course you can't go strictly by the chart, with so many other things affecting ph, but there should not be a problem establishing a base line standard in my tank, like you said using a drop checker, and using the ph controller to keep the c02 levels constant without having to check them.
Does that sound reasonable?
 

Tom Barr

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In 2 weeks, the level of growth in my tanks would throw off the CO2, nutrients and would be nothing more than a moving target.

You need an automated pruning device to go along with all the rest.
Auto dosing is not going to give the results you think.

How does growth affect things?
Water flow?
CO2, lighting, nutrient demand(does 2-3x more biomass, 3x more light as it grows to the surface use less, or more CO2 and nutrients?).


You cannot automate somethings.
You only have a few things and few trade offs.

Given these constraints, non CO2 might be wiser.

Regards,
Tom Barr
 

quatermass

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Oct 4, 2005
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Kh is often neglected

calihawker;23521 said:
The real question I'd like to know is why people don't use potassium bicarbonate? Is it the availability or the price or both? If you had the choice and everything was equal would you use sodium or potassium?

Steve

I've used Potassium carbonate, Sodium bicarbonate and Potassium bicarbonate.

It's very hard to get Potassium bicarbonate in less than 20Kg bags! Plus of course it has a side-effect of altering the pH of the water.
It dissolves very fast and raises KH and pH.

Potassium carbonate only raises KH. Though it takes longer to dissolve in the water. I live in Scotland where the water is ~0 GH and ~1 KH...

Aqua Essentials sells Potassium carbonate. If you know of a USA seller, I'd be interested as I need a USA supplier for the following page:

Potassium carbonate - The Aquarium Wiki

I'd prefer to use Potassium carbonate, then Potassium bicarbonate then Sodium bicarbonate. But the last item is the easiest to get and cheapest.

If you want to add K and only raise KH, get Potassium carbonate.
 

travis

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Tom Barr;23605 said:
You need an automated pruning device to go along with all the rest.

Oh, that sounds like something I would really be interested in having. Can I set it to top and replant, or does it only do pruning? My early experiments with automated pruning devices only ended in disaster: the silicone-sealed Roomba, augmented with scissors and suction cup wheels, left a wake of destruction in my tank and soon became wedged behind some driftwood and ended up gnawing its way through my filter intake pipe right before it shorted out and electrocuted my fish. I'm glad someone has finally gotten it figured out ;)
 

Tom Barr

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Larger scissors makes the job easier if you are a "topper" pruner.
I've been more a uprooting pruner most of my life and topping was an easy out.
Some plants respond well to topping, some do not.

Some like most things , a trade off ensues.........a mix of both methods seems best.
Still,. if you need KH, KHCO3 works nicely.

Regards,
Tom Barr
 

quatermass

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It's a common baking additive so I was told, so ask a chef?
Actually I found it hard to find without being asked to buy 50Kg of it!

It's nice stuff, much better than Sodium bicarbonate as it gives your tank potassium.

I just wish it was available in smaller quantities here in the UK.