Alright NEWBIE, time for a Test

WaterKeeper

Bogus Information Expert
Premium Member
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. :D

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. :D

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 :D. 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. :D

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 :D) 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:
 
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Awestralian said:
Bumparoonie!
:strooper:

Is that one of those Aussie Aboringinnie words?:D

I do have a little to add here. Got a PM from Nancy asking:

This alkalinity thing is confusing. I thought PH and alkalinity are the same.

Well Nancy I really didn't try to explain the two in my post. Let me try it this way.

Suppose we have 2 buildings maybe 10x10x8. They are identical in every respect right down to the shingles on the roof. Both have a refrigeration unit of exactly the same type and ability attached for cooling. Right now both are at 80 degrees but we want to store some chilled beer in them so we need to lower the temperature of both to 35 degrees. There is one, and only one, difference between the two. The second building has a big block of solid iron, lets say 4x4x3, sitting in the middle of it.

What? How should I know why there is a block of iron in the one building? Maybe they read Doc Randy's post on adding iron to their tanks and wanted some on hand. Sheesh, this is an analogy Newbie, it is fictional and it makes no difference why there is a block of iron in one. Just pretend it is there, OK!

ANYHOW, we start up our refrigeration units on each building. About 4 hours latter we return and check the temperature. Great building one, without the iron block, is down to 67 degrees. But wait! The other building, with the iron block, is only down to 78 degrees. Something must be wrong with the refrigeration unit. We check it out and it is working perfectly.

We go away and come back about 8 hours latter and building one is down to 44 degrees but building two is only at 69 degrees. Humm, the next day we return and and building one is at the desired 35 degree temperature but the building with the iron block is at 49 degrees and it isn't till the next day that it reached 35 degrees. What is going on here?

Well, of course, that big old dense block of iron acted as a heat sink. A sponge for heat if you will. The latent heat contained in the iron block took much longer to remove from the building than it did in the empty building. The block acted as a buffer.

In this case, if the buildings were our tanks the building with the iron block would be a building with alkalinity. Just as the iron block resisted cooling the alkalinity resists change from the acidity produced in our tanks. For heat we use the temperature scale. For acidity we use the pH scale. Both are arbitrary scales that measure a change of state. In an unbuffered tank adding a little acid will quickly change the pH. In a buffered tank the pH will not change as much with the same amount of acid added.

I hope that is understandable. I wanted to get this across without a lot of chemistry. LOL, so I switched to physics. :D
 
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For those of you that were waiting breathlessly, this is the link for SAT's FAQ on RO/DI:

<a href="http://reefcentral.com/modules.php?s=&name=Content&pa=showpage&pid=2">RO/DI FAQ</a>

Sorry about the slow response in putting up the link but my puter is sick and had to have major surgery. How I have to worry if the HMO will cover the costs. :D

Note-The RO link was working when I first posted this in 2003.
 
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WaterKeeper said:

Sorry about the slow response in putting up the link but my puter is sick and had to have major surgery. How I have to worry if the HMO will cover the costs. :D

Only if you got a referral from you primary care physician. If not, out of pocket expense!! :D

David
 
Thank you WaterKeeper!!! I'm thinking a lot of experienced people need to read your post as well. Reminds me of all the years of chemistry labs in college. :D
 
Hmmm, Beer!
beer.gif
Oh yeah, nice job breaking that down for us there also Tom.
 
why does my fastest alk kit say optimum alk is 2.5 to 5.0, but in my tank it is usually around 8.0. Is this a signal that i have too large of a fish load or a bulidup of CO2 (thats what the kit says). If alk is a buffer wouldn't more be better? I have had my fish for over a year at 8.0 and they haven't died.
 
good question stang, i was wondering the same. hey great info water keeper, i just may visit the chem forum now lol. very interesting stuff
 
Hi'O Silver Away!

OK Newbies, when you post on a thread as stale as this one is you can expect stale answers!!! ;)

Well Silver that alkalinity is indeed high. Almost twice the normal, upper recommended level. I do assume here that the 8 reading is in meq/l.

Note:, Please when posting an alkalinity question always include the units involved. We use meq/l, mg/l (ppm) and dKH to measure alkalinity and it gets confusing if one doesn't express the units they used when they took the reading.

Here, I'm pretty sure Silver is talking about meq/l.

The build-up of CO2 and bio-load are related. The more livestock we add to the tank the more respiration and therefore the more CO2 entering the water column. An overstocked tank may have high alkalinity and low pH, which is more of a problem in a tank with invertebrates than a FO tank. Labored breathing with fish can be a sign of high carbon dioxide level. It is hard to see its effect on inverts as it is more subtle.

It is not only stocking levels that can effect CO2 concentrations in a tank. Having a tight fitting cover on a tank can increase CO2. Simply removing the cover and replacing it with nylon screening or egg crate can help here. Poor circulation in the tank can inhibit gas exchange. Room air itself can have CO2 levels much higher than normal outside air levels.

Looking at your problem it appears you are probably adding a lot of sodium carbonate type buffers to your tank to maintain pH levels. A vicious cycle has started where you add buffer, pH increases, then slowly declines with time. This is because the carbonate buffer absorbs CO2 and is then converted to bicarbonate; alkalinity rises while pH drops. In most tanks this is self-controlling but if levels of CO2 are high then problems develop.

There are a few things you can do-
  • Get a second opinion-just in case your test kit is in error. Most LFS's will do it for free.
  • If you have a solid top on the tank-remove it and replace with one that aids circulation
  • Try opening a window-sealed rooms can have high levels of carbon dioxide
  • Increase circulation in the tank itself-this enhances gas exchange
  • If you run your tank at a low temperature-try increasing it to 80-82Ã"šÃ‚°F as CO2 solubility drops as temperature rises
  • Increase the frequency and volume of water changes-this removes surplus alkalinity
  • Increase tank or sump volume-the more water, the less impact from bio-loading
  • Try using KW as a buffer rather than an additive-KW tends to provide better pH adjustment with less alkalinity build-up


Any of these methods may help with your problem. Nicchick is also right. Try reading the wealth of articles Doc Randy has on the Chemistry Forum-Here-they provide a helpful of information on this very problem.

Hope that helps Kimosabi.

You'd better read those Chemistry articles Maggot cause there will be a stoichiometry test on carbonate chemistry tomorrow! :D
 
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waterkeeper:

thanks for the information, I will check out the chem. forums. I used a fastest kit that mesures alk. in meq/L, also my lid does fit very tight. I only have one powerhead for circulation, but I want to order a few more. Any suggestions on a good, compact powerhead for a 29g (the smaller the pump the better as long as it still flows good). I will try increasing the circulation with the powerheads, getting my alk checked by LFS, and replacing the top with something less restrictive. I will post if this works out or not. Thanks for your help!
 
whats the shelf life of a test kit? do the test chemicals ever "go bad" or lose potency?

sounds like i'm talking about old meds haha
 
Loyalty,

As I mentioned in the post that starts this thread, the liquid mixed indicator used in the alkalinity test has a fairly short shelf live; around 2-3 months. Dry indicators are much better, lasting at least a year.

Silver,

You have some fish that get pretty big in that tank. It might be time for an upgrade. If you can't do that right now you might consider setting up a small sump; like 10 gallons or so.

The Bak Pac skimmer should be helping with gas exchange. After you confirm your test results I'd do the water change thing first. Following that I'd prehaps see how things go with a window cracked. It may be the room air is the culprit. Of course, in Brookfield, things may be a bit frosty when you do that. :D
 
WaterKeeper:

I just tested alk and it was 2.5 meq/L. I used to add c-balance for calcium and buffer, and my calcium never went above 350. I recently tried adding seachem reef complete and I overdosed calcium to like 550ppm. I did a 10g water change and I am still trying to get the calcium down to normal. The Articles you suggested helped me understand the calcium/ alk procedure better. I plan to try to get calcium / alk at the correct levels with the seachem buffer and reef complete and then maintain those levels with the c-balance. Does this sound like a good plan? Also, I am looking into a sump/ref. I am very handy and I have an extra 10g in the garage so I am kicking around the idea of building my own. Still, I don't quite get how the whole overflow / sump thing works without overflowing or running dry. Do you know of any good articles on this? I am currently exploring melev's reef, but the concept is still confusing to me.
 
For crying out loud what's with you Newbies? This is a test kit thread and you want me to explain sump plumbing? Give me a break! :D

Ok, Ok you have a bucket, pump, overflow and some plumbing. You hook 'em all up and have a sump. ;)

It really isn't too much more complicated than that. With a small tank you probably will be buying a hang on overflow box. A siphon (s) is used to take tank water to the box where it flows by gravity to whatever container is acting as a sump. The sump has either a submersable or exterior pump that pumps water back to the main tank. A few lengths of PVC pipe, a check valve and a couple of gate valves are used to pump it all up. It really isn't all that complicated. Marc's site has from simple to complex sumps but all really function in the same manner. If you don't feel too handy you can always get a small wet/dry. Running without the bioballs it is actually a pre-plumbed sump.

Once again, I'd take a look at Randy's articles on raising calcium levels. Right now you alkalinity seems fine. I'd use a calcium additive that doesn't increase alkalinity at this point. Calcium chloride ice melter is used by many to boost calcium and leave pH and alkalinity pretty much alone. Dow Flake ice melter is one brand said to be useful for this purpose and is pure enough not to cause problems in your tank.
 
ok back to the thread topic.... why are you saying to find a supplement that does not increase alkalinity anymore? i thought you want high alkalinity, that way, the tank is less prone to pH change. or am i oversimplifying your idea of "the piece of iron in the room"
 
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