Aquarium Advice - Aquarium Forum Community - View Single Post - How to make a reference KH solution for CO2 measurement

dapellegrini · 12-23-2006, 11:57 PM

So I broke down and did it today. Here is my photo journal, making the reference kH solution for the Drop Checker, per Tom Barr's recommendations.

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THIS LOG WAS MADE WHEN THIS SUBJECT WAS STILL VERY NEW - AND A FEW THINGS HAVE BEEN CORRECTED SINCE. INSTEAD OF 4.99 GRAMS OF BAKING SODA YOU WILL NEED 6.00. AND DO *NOT* BAKE IT AT ALL - THIS WILL CHANGE THE CHEMICAL COMPOSITION OF THE POWDER. OTHERWISE THIS IS STILL AN ACCURATE REPRESENTATION OF HOW YOU DO THIS

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First a quick list of everything I picked up for this project:

- Scale that would weigh out to the .01 grams - $20 on E-bay
- Set of graduated cylinders (10ml, 50ml, 100ml) - $20 on E-bay
- Drop Checker - Chinese ripoff version of ADA - $22 on E-bay from Hong Kong
- 10 liters of Distilled Water - $2 at local grocery store
- 2 or 3 gallon bucket - $2 at local grocery store
- 2 bottles of SOBE - cheapest way to get two glass storage bottles for the excess mixture

Things that I had laying around:

- Big sack of Baking Soda
- AP pH test kit
- Dropper from another test kit (Hagen brand)
- Liquid measure for 1 liter measurement
- small creme-brule pot to cook the Baking Soda in the oven
- little medicine dosing cup
- chopsticks - to stir my mixture

So here is the whole setup in a couple of pics:

So with everything finally gathered, off we go...

First things first, measure out a bunch of backing soda. Need quite a bit more than the required 6.00 (corrected from 4.99) grams, just incase mine is full of water and/or CO2...

This should do:

Into the Creme Brule bowl and on into the oven at 400-degrees for 1 hour (I know, the oven is a bit of a mess): *** UPDATE: Do NOT cook the baking soda - it will actually change the chemical composition of the powder and you will not have an accurate mix. I will leave the photo here for posterity sake...

One hour later, it is time to measure out 6.00 (corrected from 4.99) grams of this stuff. I have a few doubts about how accurate this cheap scale is for this, but I figure this looks about right:

Then to measure out the water. I was thinking I would find distilled water premeasured in liters, but no such luck. Good thing my wife had this pyrex measuring cup. Measured out 5 liters into the new bucket (also washed and thoroughly rinsed everything before use).

The bucket confirmed my measurements, but in quarts... I didn't think quarts were quite the same thing as liters, but again, i trust the pyrex measures.. I was eye level with the thing and perhaps a bit too anal about the measurements... you can see it exactly on the 5 line in the bucket:

Well my next dilemma was exactly what to use to mix this stuff. At each phase I was concerned about contaminating my mixture (again a bit anal, but i really didn't want to have to do this all twice). Well I settled on a super clean pair of chopsticks.

The kids drank the SOBEs and I washed, rewashed and rinsed the bottles, then labeled and filled.

The first bottle to get filled was of the 40dkH mixture straight out of the bucket. I figure 500ml should last me forever, or as long as I care to believe that it is still any good.

The second bottle required diluting... In comes the graduated cylinder. I ended up only using the 100ml one. Used a dropper from one of my Hagen test kits (again rinsed like 10 times first) to fill the first 10ml with the bucket water. Then filled the last 90ml with clean distilled water for my 4dkH solution. Repeated this 5 times, pouring each into the other SOBE bottle.

OK, now we are getting somewhere. Next, I decided to break out the AP test kit, filled the pH test to it's line and dropped in 3-drops of regent, per the instructions (UPDATE: Adding 6-8 drops will make the color much easier to read and will not otherwise change the effectiveness of your measurement - thus highly recommended to add more drops). Bingo, blue water showing 7.6 pH. Looks like we are on track:

Then I took the dropper, filled it with the test solution and squirted it into the drop checker. Bingo:

And in the aquarium it goes. Clocking the time in at 5:45pm:

And here it is now down to my base color of green (6.6 pH) at about 7:30pm. (PWC, thus all of the bubbles, and yes I know I need to pull that algae off of the spraybar)

I hope I did all of this right. Of course let me know if I did not :S ...

Also hope someone out there finds this a useful addition to this sticky. Would love to see something similar for the pH probe cap.

12-23-2006, 11:57 PM	#12
dapellegrini Aquarium Advice FINatic Join Date: Sep 2003 Location: Phoenix, AZ Posts: 870	So I broke down and did it today. Here is my photo journal, making the reference kH solution for the Drop Checker, per Tom Barr's recommendations. ************************************************ **** THIS LOG WAS MADE WHEN THIS SUBJECT WAS STILL VERY NEW - AND A FEW THINGS HAVE BEEN CORRECTED SINCE. INSTEAD OF 4.99 GRAMS OF BAKING SODA YOU WILL NEED 6.00. AND DO NOT BAKE IT AT ALL - THIS WILL CHANGE THE CHEMICAL COMPOSITION OF THE POWDER. OTHERWISE THIS IS STILL AN ACCURATE REPRESENTATION OF HOW YOU DO THIS ************************************************ ** First a quick list of everything I picked up for this project: - Scale that would weigh out to the .01 grams - $20 on E-bay - Set of graduated cylinders (10ml, 50ml, 100ml) - $20 on E-bay - Drop Checker - Chinese ripoff version of ADA - $22 on E-bay from Hong Kong - 10 liters of Distilled Water - $2 at local grocery store - 2 or 3 gallon bucket - $2 at local grocery store - 2 bottles of SOBE - cheapest way to get two glass storage bottles for the excess mixture Things that I had laying around: - Big sack of Baking Soda - AP pH test kit - Dropper from another test kit (Hagen brand) - Liquid measure for 1 liter measurement - small creme-brule pot to cook the Baking Soda in the oven - little medicine dosing cup - chopsticks - to stir my mixture So here is the whole setup in a couple of pics: So with everything finally gathered, off we go... First things first, measure out a bunch of backing soda. Need quite a bit more than the required 6.00 (corrected from 4.99) grams, just incase mine is full of water and/or CO2... This should do: Into the Creme Brule bowl and on into the oven at 400-degrees for 1 hour (I know, the oven is a bit of a mess): * UPDATE: Do NOT cook the baking soda - it will actually change the chemical composition of the powder and you will not have an accurate mix. I will leave the photo here for posterity sake... One hour later, it is time to measure out 6.00 (corrected from 4.99) grams of this stuff. I have a few doubts about how accurate this cheap scale is for this, but I figure this looks about right: Then to measure out the water. I was thinking I would find distilled water premeasured in liters, but no such luck. Good thing my wife had this pyrex measuring cup. Measured out 5 liters into the new bucket (also washed and thoroughly rinsed everything before use). The bucket confirmed my measurements, but in quarts... I didn't think quarts were quite the same thing as liters, but again, i trust the pyrex measures.. I was eye level with the thing and perhaps a bit too anal about the measurements... you can see it exactly on the 5 line in the bucket: Well my next dilemma was exactly what to use to mix this stuff. At each phase I was concerned about contaminating my mixture (again a bit anal, but i really didn't want to have to do this all twice). Well I settled on a super clean pair of chopsticks. The kids drank the SOBEs and I washed, rewashed and rinsed the bottles, then labeled and filled. The first bottle to get filled was of the 40dkH mixture straight out of the bucket. I figure 500ml should last me forever, or as long as I care to believe that it is still any good. The second bottle required diluting... In comes the graduated cylinder. I ended up only using the 100ml one. Used a dropper from one of my Hagen test kits (again rinsed like 10 times first) to fill the first 10ml with the bucket water. Then filled the last 90ml with clean distilled water for my 4dkH solution. Repeated this 5 times, pouring each into the other SOBE bottle. OK, now we are getting somewhere. Next, I decided to break out the AP test kit, filled the pH test to it's line and dropped in 3-drops of regent, per the instructions (UPDATE: Adding 6-8 drops will make the color much easier to read and will not otherwise change the effectiveness of your measurement - thus highly recommended to add more drops). Bingo, blue water showing 7.6 pH. Looks like we are on track: Then I took the dropper, filled it with the test solution and squirted it into the drop checker. Bingo: And in the aquarium it goes. Clocking the time in at 5:45pm: And here it is now down to my base color of green (6.6 pH) at about 7:30pm. (PWC, thus all of the bubbles, and yes I know I need to pull that algae off of the spraybar) I hope I did all of this right. Of course let me know if I did not :S ... Also hope someone out there finds this a useful addition to this sticky. Would love to see something similar for the pH probe cap. __________________ LIVE IN ARIZONA? COME CHECK US OUT!