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Hey guys, I thought this might be helpful:
http://jdieck1.home.comcast.net/chemcalc.html">http://jdieck1.home.comcast.net/chemcalc.html</a>
I am using it to dose my CA.
It comes in very handy and has the major doing supplement makers and their products listed.
Also, Tom Wyatt has posted this borax test on another website and I used it myself to verify the validity of my PH probe. It's a very simple, cheap test to check that your PH probe is properly calibrated and is working the way it should, to alleviate any drifts in PH, so you can make sure your readings are accurate.
Here's what he said:
"OK, it is time to use the Borax test to see if the meter will read the pH of a broad resonse sodium borate at the right pH level. This evaluates the ability of your probe to read pH correctly. If your probe cannot pass the probe test with sodium metaborate (20 mule team borax), then it is time to do the cleaning of the probe and sattempt recalibration again, and if it still will not pass the borax teset, time to replace the probe.
Calibration is good, but it is always a good idea to do a separate test with the borax to see if your meter is testing well during normal continuous usage. I read a lot of posts where folks say that they have calibrated their pH meters and followed the directions exactly, followed all the temp bath suggestions, corrected for every possible error, yet they consistently see pH values that are skewed either high or low in their aquaria based on even the new calibration. When questioned on their procedure, almost every person I have spoken with had used standards that had either expired, or been in their LFS’s shops long enough to have expired. I read with interest Craig Bingman’s posts about a similar problem with (another?) brand of Ph calibration solution where the pH 10 standard was off by almost a full pH unit. Craig had purchased a few packets of this particular brand, used a lab bench electrode, calibrated with fresh research-quality pH standards and tested these calibration fluids. After much discussion, Craig proposed that folks use a freshly prepared buffering solution of sodium metaborate that will always come to the same value under home conditions. This lead to the publishing of his article in Aquarium Frontiers on the use of 20 Mule-Team Borax to prepare a home standard solution. I would suggest that you use this procedure to make sure that your pH probe and meter are in actuality measuring what they are supposed to.
Essentially, this involves making a standard solution of borax in RO/DI water. This differs from NIST standard solutions in that NIST solution standards rely on using controlled measured amounts of an acid and its conjugate base. Usually you would need to mix precise quantities of two different compounds to make a pH standard solution in a precisely measured volume. These will have a set shelf life, and will deteriorate more rapidly if exposed to less than ideal conditions. Rather than try and make these lab standards (you could, if you had the precision lab ware needed to measure end volume and the acid and conjugate base weights), we can use the properties of sodium metaborate in water to form these equimolar acid/conjugate bases for us (Boric acid and hydrated borate ions). This is one of the advantages of using borax as a standard.
[B]pH of Sodium Metaborate Standard Solutionat Various Temperatures[/B]
[I](3.80 grams Na2BO7 10H2O/liter) </em>
<u>Degrees Celsius</u> . . . <u>Degrees Fahrenheit</u> . . . . . . <u>pH</u>
0 . . . . . . . . . . . . . . 32.0 . . . . . . . . . . . . . 9.464
5 . . . . . . . . . . . . . . 41.0 . . . . . . . . . . . . . 9.395
10 . . . . . . . . . . . . . 50.0 . . . . . . . . . . . . . 9.332
15 . . . . . . . . . . . . . 59.0 . . . . . . . . . . . . . 9.276
16 . . . . . . . . . . . . . 60.8 . . . . . . . . . . . . . 9.266
17 . . . . . . . . . . . . . 62.6 . . . . . . . . . . . . . 9.256
18 . . . . . . . . . . . . . 64.4 . . . . . . . . . . . . . 9.245
19 . . . . . . . . . . . . . 66.2 . . . . . . . . . . . . . 9.235
20 . . . . . . . . . . . . . 68.0 . . . . . . . . . . . . . 9.225
21 . . . . . . . . . . . . . 69.8 . . . . . . . . . . . . . 9.216
22 . . . . . . . . . . . . . 71.6 . . . . . . . . . . . . . 9.207
23 . . . . . . . . . . . . . 73.4 . . . . . . . . . . . . . 9.198
24 . . . . . . . . . . . . . 75.2 . . . . . . . . . . . . . 9.192
25 . . . . . . . . . . . . . 77.0 . . . . . . . . . . . . . 9.180
26 . . . . . . . . . . . . . 78.8 . . . . . . . . . . . . . 9.172
27 . . . . . . . . . . . . . 80.6 . . . . . . . . . . . . . 9.167
28 . . . . . . . . . . . . . 82.4 . . . . . . . . . . . . . 9.155
29 . . . . . . . . . . . . . 84.2 . . . . . . . . . . . . . 9.147
30 . . . . . . . . . . . . . 86.0 . . . . . . . . . . . . . 9.139
35 . . . . . . . . . . . . . 95.0 . . . . . . . . . . . . . 9.081
40 . . . . . . . . . . . . . 104.0 . . . . . . . . . . . . 9.068
[B]Characteristics of Sodium Metaborate pH Standard solution [/B]
[I]<u>Characteristic</u> . . . . . . . . . . . . . . . . . . . . . . . . <u>Value</u></em>
Composition(gm Na2B4O7 10H2O/1000 ml) . . . . . . 3.80
molality (m) . . . . . . . . . . . . . . . . . . . . . . . . . . 0.01
Molarity (M). . . . . . . . . . . . . . . . . . . . . . . . . . 0.009971
pH at 25 degrees Celsius . . . . . . . . . . . . . . . . . 9.180
change in pH after dilution
to half original concentrationin water .. . . . . . . . +0.01
Temperature coef.
dpH/dt,unit degrees Celsius-1 . . . . . . . . . . . . . -0.0082
<span style="font-size: 11px;">[I]data taken from C.Bingman Aquarium Frontiers article</em></span>
These tables give the properties of differing temperatures on the pH of borax (sodium metaborate) in purified water and the resulting pH, as well as the characteristics that allow us to demonstrate the relatively small change that varying the concentration of the solution has on pH when compared to the standard solution. To make the textbook standard, you dissolve 3.8 grams of borax per liter water using a lab balance and a volumetric flask. Fortunately 1/2 level teaspoon of solid borax weighs just about two grams, AND the pH of borax solutions is only weakly dependent on the concentration of borax in the solution (SEE CHART), SOOOOOooooo, we don’t need to be tremendously precise in our measurement of the borax to still produce a relatively accurate pH standard. We can make a useful product here without the use of a lab balance.
Use a pint of water (473ml) and add a half teaspoon (1/2 level tsp.) of borax to make a resultant pH standard solution with 2 gm of sodium metaborate per 473 ml or 4.3 grams of sodium metborate/litre. Although using this method to make the standard will only result in an accuracy of about plus or minus 10% of the lab standard sodium metaborate pH calibration solution, there is such a weak dependence of pH on concentration of the solute buffer here that it is close enough for our purposes. To use this solution, calibrate your system with your bought standards, allowing 10 minutes for equilibration at both set-points, and then use a freshly mixed borax standard solution to check that calibration. Any significant variance in expected values will indicate either errors in calibration or degradation of the standards at this point.
Plan on replacing the pH probes about every 18 to 24 months, although in rare instances the probes can last for as long as 3 to 4 years when immersed continuously in no-light environments and still give fairly close responses..."
For those that don't speak Tom, you first calibrate your PH probe with your solutions (which you should do monthly anyways) , then take a pint of RO/DI water, add 1/2 teaspoon of the Borax powder, stir it up for alittle while, put your PH probe in it and let it sit for 10 minutes or so, take the temp reading from the water and look at the chart above and match the temp and whatever the PH reading is should be what your PH meter shows. If they match up, then you know your probe and calibration solutions are good. If not, then your calibration solutions might be out of date, or your probe might need to be cleaned or even replaced.
Mine tested about 3 hundredths off, so not too bad there.
You can buy the Borax Powder at Publix and at Target. It's located in the deteregent section and is in powder form. It's made by 20 Mule Team and I ended up buying a 4 lb box, b/c that's all they had and it cost me like $3. So even if I tested the probe every month, it would still probably outlive me.
Anyways, I just thought this could be a sticky or placed somewhere convenient for all to see and use. It really has helped me alot and I think it could help others as well.
Thanks.
http://jdieck1.home.comcast.net/chemcalc.html">http://jdieck1.home.comcast.net/chemcalc.html</a>
I am using it to dose my CA.
It comes in very handy and has the major doing supplement makers and their products listed.
Also, Tom Wyatt has posted this borax test on another website and I used it myself to verify the validity of my PH probe. It's a very simple, cheap test to check that your PH probe is properly calibrated and is working the way it should, to alleviate any drifts in PH, so you can make sure your readings are accurate.
Here's what he said:
"OK, it is time to use the Borax test to see if the meter will read the pH of a broad resonse sodium borate at the right pH level. This evaluates the ability of your probe to read pH correctly. If your probe cannot pass the probe test with sodium metaborate (20 mule team borax), then it is time to do the cleaning of the probe and sattempt recalibration again, and if it still will not pass the borax teset, time to replace the probe.
Calibration is good, but it is always a good idea to do a separate test with the borax to see if your meter is testing well during normal continuous usage. I read a lot of posts where folks say that they have calibrated their pH meters and followed the directions exactly, followed all the temp bath suggestions, corrected for every possible error, yet they consistently see pH values that are skewed either high or low in their aquaria based on even the new calibration. When questioned on their procedure, almost every person I have spoken with had used standards that had either expired, or been in their LFS’s shops long enough to have expired. I read with interest Craig Bingman’s posts about a similar problem with (another?) brand of Ph calibration solution where the pH 10 standard was off by almost a full pH unit. Craig had purchased a few packets of this particular brand, used a lab bench electrode, calibrated with fresh research-quality pH standards and tested these calibration fluids. After much discussion, Craig proposed that folks use a freshly prepared buffering solution of sodium metaborate that will always come to the same value under home conditions. This lead to the publishing of his article in Aquarium Frontiers on the use of 20 Mule-Team Borax to prepare a home standard solution. I would suggest that you use this procedure to make sure that your pH probe and meter are in actuality measuring what they are supposed to.
Essentially, this involves making a standard solution of borax in RO/DI water. This differs from NIST standard solutions in that NIST solution standards rely on using controlled measured amounts of an acid and its conjugate base. Usually you would need to mix precise quantities of two different compounds to make a pH standard solution in a precisely measured volume. These will have a set shelf life, and will deteriorate more rapidly if exposed to less than ideal conditions. Rather than try and make these lab standards (you could, if you had the precision lab ware needed to measure end volume and the acid and conjugate base weights), we can use the properties of sodium metaborate in water to form these equimolar acid/conjugate bases for us (Boric acid and hydrated borate ions). This is one of the advantages of using borax as a standard.
[B]pH of Sodium Metaborate Standard Solutionat Various Temperatures[/B]
[I](3.80 grams Na2BO7 10H2O/liter) </em>
<u>Degrees Celsius</u> . . . <u>Degrees Fahrenheit</u> . . . . . . <u>pH</u>
0 . . . . . . . . . . . . . . 32.0 . . . . . . . . . . . . . 9.464
5 . . . . . . . . . . . . . . 41.0 . . . . . . . . . . . . . 9.395
10 . . . . . . . . . . . . . 50.0 . . . . . . . . . . . . . 9.332
15 . . . . . . . . . . . . . 59.0 . . . . . . . . . . . . . 9.276
16 . . . . . . . . . . . . . 60.8 . . . . . . . . . . . . . 9.266
17 . . . . . . . . . . . . . 62.6 . . . . . . . . . . . . . 9.256
18 . . . . . . . . . . . . . 64.4 . . . . . . . . . . . . . 9.245
19 . . . . . . . . . . . . . 66.2 . . . . . . . . . . . . . 9.235
20 . . . . . . . . . . . . . 68.0 . . . . . . . . . . . . . 9.225
21 . . . . . . . . . . . . . 69.8 . . . . . . . . . . . . . 9.216
22 . . . . . . . . . . . . . 71.6 . . . . . . . . . . . . . 9.207
23 . . . . . . . . . . . . . 73.4 . . . . . . . . . . . . . 9.198
24 . . . . . . . . . . . . . 75.2 . . . . . . . . . . . . . 9.192
25 . . . . . . . . . . . . . 77.0 . . . . . . . . . . . . . 9.180
26 . . . . . . . . . . . . . 78.8 . . . . . . . . . . . . . 9.172
27 . . . . . . . . . . . . . 80.6 . . . . . . . . . . . . . 9.167
28 . . . . . . . . . . . . . 82.4 . . . . . . . . . . . . . 9.155
29 . . . . . . . . . . . . . 84.2 . . . . . . . . . . . . . 9.147
30 . . . . . . . . . . . . . 86.0 . . . . . . . . . . . . . 9.139
35 . . . . . . . . . . . . . 95.0 . . . . . . . . . . . . . 9.081
40 . . . . . . . . . . . . . 104.0 . . . . . . . . . . . . 9.068
[B]Characteristics of Sodium Metaborate pH Standard solution [/B]
[I]<u>Characteristic</u> . . . . . . . . . . . . . . . . . . . . . . . . <u>Value</u></em>
Composition(gm Na2B4O7 10H2O/1000 ml) . . . . . . 3.80
molality (m) . . . . . . . . . . . . . . . . . . . . . . . . . . 0.01
Molarity (M). . . . . . . . . . . . . . . . . . . . . . . . . . 0.009971
pH at 25 degrees Celsius . . . . . . . . . . . . . . . . . 9.180
change in pH after dilution
to half original concentrationin water .. . . . . . . . +0.01
Temperature coef.
dpH/dt,unit degrees Celsius-1 . . . . . . . . . . . . . -0.0082
<span style="font-size: 11px;">[I]data taken from C.Bingman Aquarium Frontiers article</em></span>
These tables give the properties of differing temperatures on the pH of borax (sodium metaborate) in purified water and the resulting pH, as well as the characteristics that allow us to demonstrate the relatively small change that varying the concentration of the solution has on pH when compared to the standard solution. To make the textbook standard, you dissolve 3.8 grams of borax per liter water using a lab balance and a volumetric flask. Fortunately 1/2 level teaspoon of solid borax weighs just about two grams, AND the pH of borax solutions is only weakly dependent on the concentration of borax in the solution (SEE CHART), SOOOOOooooo, we don’t need to be tremendously precise in our measurement of the borax to still produce a relatively accurate pH standard. We can make a useful product here without the use of a lab balance.
Use a pint of water (473ml) and add a half teaspoon (1/2 level tsp.) of borax to make a resultant pH standard solution with 2 gm of sodium metaborate per 473 ml or 4.3 grams of sodium metborate/litre. Although using this method to make the standard will only result in an accuracy of about plus or minus 10% of the lab standard sodium metaborate pH calibration solution, there is such a weak dependence of pH on concentration of the solute buffer here that it is close enough for our purposes. To use this solution, calibrate your system with your bought standards, allowing 10 minutes for equilibration at both set-points, and then use a freshly mixed borax standard solution to check that calibration. Any significant variance in expected values will indicate either errors in calibration or degradation of the standards at this point.
Plan on replacing the pH probes about every 18 to 24 months, although in rare instances the probes can last for as long as 3 to 4 years when immersed continuously in no-light environments and still give fairly close responses..."
For those that don't speak Tom, you first calibrate your PH probe with your solutions (which you should do monthly anyways) , then take a pint of RO/DI water, add 1/2 teaspoon of the Borax powder, stir it up for alittle while, put your PH probe in it and let it sit for 10 minutes or so, take the temp reading from the water and look at the chart above and match the temp and whatever the PH reading is should be what your PH meter shows. If they match up, then you know your probe and calibration solutions are good. If not, then your calibration solutions might be out of date, or your probe might need to be cleaned or even replaced.
Mine tested about 3 hundredths off, so not too bad there.
You can buy the Borax Powder at Publix and at Target. It's located in the deteregent section and is in powder form. It's made by 20 Mule Team and I ended up buying a 4 lb box, b/c that's all they had and it cost me like $3. So even if I tested the probe every month, it would still probably outlive me.
Anyways, I just thought this could be a sticky or placed somewhere convenient for all to see and use. It really has helped me alot and I think it could help others as well.
Thanks.
