KITS THAT IS!!!
Yeah it's about time for some test kits but before I get into that, here is an article by Jedi candidate SAT. He covers many of the questions asked in his Jedi thesis <a href="http://reefcentral.com/modules.php?s=&name=Content&pa=showpage&pid=2">RO/DI FAQ</a>. I helped by giving him the line, "size does matter", although I can't remember if it was RO/DI that we were talking about.
It is good reading and packed full of good poop.
Imagine, SAT almost turned to the Darkside. Awhile back, we sensed great fear in SAT and found he was dosing multi-purpose additives. Can you imagine, without even testing to see if his tank was low on what he was adding. As the ancient Jedi proverb goes; "Additives you add, then test you must."
Dosing is just one reason to run tests on your tank. As a Newbie, you want to check the state of your cycle by ammonia testing. When your tank is established, tests can give you a handle on the overall health of your tank. When you have a problem testing can tell you; what has changed?
The good part is you don't need to be one of those smart-@ss CHEMISTRY GEEKS that have been known to lurk on this board and dispense their evil, non-decipherable malarkey. . Well, we do allow Doc Randy but he, as you know, is a droid.
As a hobbyist, you basically have three classes of tests you can run. The first is volumetric, where you add a solution that reacts with the substance you wish to find. Examples are the alkalinity test and calcium. The second is a colorimetric test where the substances sort after react with a dye. The intensity of the color tells you how much there is. Ammonia, nitrite and nitrate tests are all examples of colorimetric tests. Lastly we have instrumental methods where an instrument gives you a direct reading of the quantity of the unknown. Examples are TDS, pH and salinity. There are literally dozens of test kits you can buy but all of them can be grouped into these three basic classes. Let's take a closer look at each class and a few of the most commonly used tests in that class.
Volumetric kits rely on a technique know as titration. A solution of known concentration is mixed with a water sample that contains an unknown. An indicator is added that, when the reaction between the known solution and the unknown in the sample is complete, produces a color change.
The most common, and one of the most important for a person with a new tank, is alkalinity. Alkalinity is the ability of your tank to resist a change in pH. A tank with low alkalinity will be subject to much wider pH swings than a tank with higher alkalinity. The actual chemicals that make up alkalinity are hydroxides (strong bases), carbonates (mid-range bases) and bicarbonates (weak bases). Borates also are included in this group but we'll kind of ignore them to keep things simple.
HOLD IT RIGHT THERE!!! I see some of you heading for the door. NOBODY said it was easy to be a REEFER! HECK, if it was easy EVERYONE would have a reef tank.
As your tank becomes established alkalinity tends to become somewhat self-adjusting. On a new tank it can be a major concern. That is because the biological processes in your tank are in a growth phase. Remember what I said when we talked about nitrification; Nitrification EATS alkalinity. In a new tank it is not unusual to need to add a supplement to increase alkalinity.
The only way to know if we are low in alkalinity is to test for it. That is accomplished by using test kit. The alkalinity kit is one of the simplest. It usually has a solution of known concentration, called the titrant, an indicator and a measuring device to collect the correct sample size. In a lab the titrant is placed in a buret. This is a long, graduated tube that is marked, usually in milliliter. In test kits you usually get a dropping bottle, or srynge in place of the buret. You collect the proper size sample, add indicator then add the dropping solution drop by drop until the sample changes to the proper color, called an endpoint. By counting up the drops you used you just multiply by a conversion factor and, presto, you have the alkalinity.
Wait a dog-gone minute! DID I SEE YOU YAWN OVER THERE??? What's the matter? You and your girlfriend stay up all night watching the POD races in your tank? Drop and give me 20 kilojoules! Anyway-
The solution in the dropping bottle is usually a very weak solution of sulfuric acid. Don't worry I REALLY mean WEAK. The indicator used will vary by kit manufacturer. Methyl Orange was the original indicator used. It changes from an orange to a reddish hue at the endpoint. Some people have trouble detecting this color change. A mixed indicator, Bromcresol Green-Methyl Red, is often used as a replacement. It changes from an aquamarine to a pink color at the endpoint. The color change is not as exact as that produced by methyl orange. If you have a pH meter, and are unsure of the endpoint, you can check the pH at what you think is the correct number of drops. It should be pH 4.5 ±0.2. If you don't have a pH meter, then get some RO/DI water and add a little indicator. Now put in a drop of the titrating solution. The color should change immediately and this is the color you want.
If you have the bromcrecol green type indicator and it is in solution be mindful , my young Padawans, that it has a somewhat limited shelf life. If you are getting strange colors at the endpoint it is probably the indicator. Also, when you stir the sample do it gently. Carbon dioxide can be adsorbed from the air if you stir vigorously causing low results. Samples with very low alkalinity, below 50 ppm, are difficult to test accurately and results will be low. Hopefully, that won't matter as when the alkalinity is that low you are going to adjust it anyway.
Before we move on there is one other little detail. Above I used parts per million. Actually, I meant parts per million as calcium carbonate. Why? Because that is the unit we use in environmental labs. Your test kit may use other units so be sure you know what unit you are using when asking for help, as I know you will , on this board
. Common units are milligrams per liter mg/l ( same as ppm) , milliequivalents per liter, meq/l and , German alkalinity units, dKH. It is easy to confuse meq/l and dKH as their ranges overlap. We can end up telling you your alkalinity is on the low side when it is normal because we thought you meant dKH and you gave us meg/l. RC provides a calculator to ease the transition from one unit to another-Unit Calculator. In general, us REAL chemists use ppm or mg/l (they're the same), the Expert Droids like meq/l and the Axis powers go by dKH. 
What? OK, you can go to the latrine. I know this is getting kinda long but I want to wrap up volumetric analysis today before you take a break.
The other popular, and useful, volumetric kit is Calcium. The titrant here is EDTA (ethylenediamine tetraacetic acid, as I am sure you were wondering), an indicator specific for calcim (you don't even want to ask its name
) and in this case a buffer solution(s) (sodium hydroxide). The latter may be a separate solution or combined with the indicator in dry powder formulations. A word about dry powders. IMO it is best to use kits that use powders as opposed to solutions. The key here is shelf life. Very often these test kits sit around before shipment. Many liquid reagents deteriorate over time. Dry reagents are usually more stable and normally can be stored for at least a year.
Returning to the calcium test. It works just like the alkalinity titration. A buffer is added to increase the pH and to precipitate magnesium which could interfere. Cloudiness in the sample is normal after the buffer addition and does not hurt the outcome. The titrant is added again drop wise. The indicator changes from pink to purple to sky blue which signals the endpoint. It is the "pure" blue that gets people confused. This test has what is known in the trade as a "fugitive" endpoint. That is you get to what you think is true blue but a second latter it appears purple again. You add a drop or two and it looks good but again it changes back to purple. This can occur over and over again and drive you nuts! This is because EDTA is a powerful reagent when it comes to putting calcium into solution. It is used in those products your mommy dear sprays on the shower stall to keep the film, which comes from your dirty newbie bode, off the shower wall. In the test it tends to dissolve colloidal calcium carbonate in the sample and bring it into solution. This results in the indicator keeps going back to a purple color. When it first turns pure blue STOP, that is the endpoint. To check on the blue you want, again, add all the reagents to some RO/DI water and a drop or so of titrant. As the Jedi master says, "The blue you see is what you seek." One last word on calcium; once you start the test don't delay. The buffer system may precipitate calcium at the pH involved and give low results if you don't finish the analysis immediately.
Another major volumetric test used by some is total hardness. This is a measure of both calcium and magnesium. Its main benefit is if you run calcium and total hardness you get the magnesium by subtracting the calcium value from the total hardness value. There is a bit of conversion math involved to do this and I'm getting weary so; Go pester the Chemistry Droid Randy at his Forum. His favorite subject always was stoic. Better yet, talk to his evil clone Habib. All he does all day is translate test kit instruction from their original Babylonian into Dutch anyway.
We'll cover the Colorimetric Tests next time. I can see those looks of grim anticipation already on your little newbie faces.:lol:
Yeah it's about time for some test kits but before I get into that, here is an article by Jedi candidate SAT. He covers many of the questions asked in his Jedi thesis <a href="http://reefcentral.com/modules.php?s=&name=Content&pa=showpage&pid=2">RO/DI FAQ</a>. I helped by giving him the line, "size does matter", although I can't remember if it was RO/DI that we were talking about.

It is good reading and packed full of good poop.
Imagine, SAT almost turned to the Darkside. Awhile back, we sensed great fear in SAT and found he was dosing multi-purpose additives. Can you imagine, without even testing to see if his tank was low on what he was adding. As the ancient Jedi proverb goes; "Additives you add, then test you must."
Dosing is just one reason to run tests on your tank. As a Newbie, you want to check the state of your cycle by ammonia testing. When your tank is established, tests can give you a handle on the overall health of your tank. When you have a problem testing can tell you; what has changed?
The good part is you don't need to be one of those smart-@ss CHEMISTRY GEEKS that have been known to lurk on this board and dispense their evil, non-decipherable malarkey. . Well, we do allow Doc Randy but he, as you know, is a droid.

As a hobbyist, you basically have three classes of tests you can run. The first is volumetric, where you add a solution that reacts with the substance you wish to find. Examples are the alkalinity test and calcium. The second is a colorimetric test where the substances sort after react with a dye. The intensity of the color tells you how much there is. Ammonia, nitrite and nitrate tests are all examples of colorimetric tests. Lastly we have instrumental methods where an instrument gives you a direct reading of the quantity of the unknown. Examples are TDS, pH and salinity. There are literally dozens of test kits you can buy but all of them can be grouped into these three basic classes. Let's take a closer look at each class and a few of the most commonly used tests in that class.
Volumetric kits rely on a technique know as titration. A solution of known concentration is mixed with a water sample that contains an unknown. An indicator is added that, when the reaction between the known solution and the unknown in the sample is complete, produces a color change.
The most common, and one of the most important for a person with a new tank, is alkalinity. Alkalinity is the ability of your tank to resist a change in pH. A tank with low alkalinity will be subject to much wider pH swings than a tank with higher alkalinity. The actual chemicals that make up alkalinity are hydroxides (strong bases), carbonates (mid-range bases) and bicarbonates (weak bases). Borates also are included in this group but we'll kind of ignore them to keep things simple.
HOLD IT RIGHT THERE!!! I see some of you heading for the door. NOBODY said it was easy to be a REEFER! HECK, if it was easy EVERYONE would have a reef tank.
As your tank becomes established alkalinity tends to become somewhat self-adjusting. On a new tank it can be a major concern. That is because the biological processes in your tank are in a growth phase. Remember what I said when we talked about nitrification; Nitrification EATS alkalinity. In a new tank it is not unusual to need to add a supplement to increase alkalinity.
The only way to know if we are low in alkalinity is to test for it. That is accomplished by using test kit. The alkalinity kit is one of the simplest. It usually has a solution of known concentration, called the titrant, an indicator and a measuring device to collect the correct sample size. In a lab the titrant is placed in a buret. This is a long, graduated tube that is marked, usually in milliliter. In test kits you usually get a dropping bottle, or srynge in place of the buret. You collect the proper size sample, add indicator then add the dropping solution drop by drop until the sample changes to the proper color, called an endpoint. By counting up the drops you used you just multiply by a conversion factor and, presto, you have the alkalinity.
Wait a dog-gone minute! DID I SEE YOU YAWN OVER THERE??? What's the matter? You and your girlfriend stay up all night watching the POD races in your tank? Drop and give me 20 kilojoules! Anyway-
The solution in the dropping bottle is usually a very weak solution of sulfuric acid. Don't worry I REALLY mean WEAK. The indicator used will vary by kit manufacturer. Methyl Orange was the original indicator used. It changes from an orange to a reddish hue at the endpoint. Some people have trouble detecting this color change. A mixed indicator, Bromcresol Green-Methyl Red, is often used as a replacement. It changes from an aquamarine to a pink color at the endpoint. The color change is not as exact as that produced by methyl orange. If you have a pH meter, and are unsure of the endpoint, you can check the pH at what you think is the correct number of drops. It should be pH 4.5 ±0.2. If you don't have a pH meter, then get some RO/DI water and add a little indicator. Now put in a drop of the titrating solution. The color should change immediately and this is the color you want.
If you have the bromcrecol green type indicator and it is in solution be mindful , my young Padawans, that it has a somewhat limited shelf life. If you are getting strange colors at the endpoint it is probably the indicator. Also, when you stir the sample do it gently. Carbon dioxide can be adsorbed from the air if you stir vigorously causing low results. Samples with very low alkalinity, below 50 ppm, are difficult to test accurately and results will be low. Hopefully, that won't matter as when the alkalinity is that low you are going to adjust it anyway.
Before we move on there is one other little detail. Above I used parts per million. Actually, I meant parts per million as calcium carbonate. Why? Because that is the unit we use in environmental labs. Your test kit may use other units so be sure you know what unit you are using when asking for help, as I know you will , on this board


What? OK, you can go to the latrine. I know this is getting kinda long but I want to wrap up volumetric analysis today before you take a break.
The other popular, and useful, volumetric kit is Calcium. The titrant here is EDTA (ethylenediamine tetraacetic acid, as I am sure you were wondering), an indicator specific for calcim (you don't even want to ask its name

Returning to the calcium test. It works just like the alkalinity titration. A buffer is added to increase the pH and to precipitate magnesium which could interfere. Cloudiness in the sample is normal after the buffer addition and does not hurt the outcome. The titrant is added again drop wise. The indicator changes from pink to purple to sky blue which signals the endpoint. It is the "pure" blue that gets people confused. This test has what is known in the trade as a "fugitive" endpoint. That is you get to what you think is true blue but a second latter it appears purple again. You add a drop or two and it looks good but again it changes back to purple. This can occur over and over again and drive you nuts! This is because EDTA is a powerful reagent when it comes to putting calcium into solution. It is used in those products your mommy dear sprays on the shower stall to keep the film, which comes from your dirty newbie bode, off the shower wall. In the test it tends to dissolve colloidal calcium carbonate in the sample and bring it into solution. This results in the indicator keeps going back to a purple color. When it first turns pure blue STOP, that is the endpoint. To check on the blue you want, again, add all the reagents to some RO/DI water and a drop or so of titrant. As the Jedi master says, "The blue you see is what you seek." One last word on calcium; once you start the test don't delay. The buffer system may precipitate calcium at the pH involved and give low results if you don't finish the analysis immediately.
Another major volumetric test used by some is total hardness. This is a measure of both calcium and magnesium. Its main benefit is if you run calcium and total hardness you get the magnesium by subtracting the calcium value from the total hardness value. There is a bit of conversion math involved to do this and I'm getting weary so; Go pester the Chemistry Droid Randy at his Forum. His favorite subject always was stoic. Better yet, talk to his evil clone Habib. All he does all day is translate test kit instruction from their original Babylonian into Dutch anyway.
We'll cover the Colorimetric Tests next time. I can see those looks of grim anticipation already on your little newbie faces.:lol:
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