Water Parameters and Test Kits

Whether your tank setup and fish are brand new or decades old, adequate water quality is essential to your fish’s lives. The only truly consistent way to keep track of your water parameters is, of course, to regularly test them. Test kits were briefly discussed in the basic equipment section of this blog, but will be covered here in more detail. Later in this section I will discuss methods and effectiveness of adjusting water chemistry.

The test kits essential to keeping an aquarium are ammonia, nitrite, nitrate and pH test kits. GH (general, or calcium hardness), KH (carbonate hardness, or alkalinity), chlorine, iron, copper, phosphorus and other test kits can give you useful information, but for most aquarists these are not necessary parameters to monitor. Any test kit can give useful information, but many of these test kits are simply a waste of money for the average hobbyist. You need to make sure that the test kits you have are relatively new. The chemicals that are used in these kits do not remain stable forever, and can break down enough to render your kit useless in less than a year from when you buy it in some cases. You would have to research the reagents used in each kit and their chemical properties to know what kits can last for how long, but a good general rule is to dump any kits you have that are over a year old, or to check your results with a newer test kit you have access to if you think your test kit is losing accuracy.

The type of test kit for each parameter you test is important as well, since not all test kits are created equal. Just because it tests for something and has measurements in, say, parts per million (ppm) does not mean it is really that accurate, or even that it is just testing for that chemical. Dip strip test kits are generally the worst type you can get. The only advantage they have is that they are easy to use. These kits are in general less precise and more expensive than liquid reagent test kits. For example, a kit that tests for ammonia and can perform 130 tests using liquid reagents is precise to 0.25 ppm and can be bought for $6.00, while a 0.5 ppm sensitive dip strip box with 25 single use strips costs $14.00. There are of course varying degrees of quality within liquid reagent test kits as well. The inexpensive test kits are not terribly accurate, but generally tell you what you need to know about your water conditions. They can tell you, for example, whether you have no nitrite, or a little nitrite, or a lot of nitrite, even if they can’t accurately measure 0.25 ppm. Remember, just because a test kit has color gradients for quarters of a part per million does NOT mean it is actually accurate to that sensitivity. The kit may have a margin of error of 1-2 or more ppm. There are also available quite costly test kits that are very accurate, so you know if it reads 1.0 ppm, you have that much in your tank, with a very small margin of error. However, at sometimes over a dollar PER TEST, very few aquarium keepers need tests that accurate or expensive. If you have that kind of money, you should first upgrade all of your equipment such as tank, filters, lighting, heaters and fish before you spend that much money on test kits. To me it seems silly to spend $40 for each test kit for a tank holding $15 in fish.

Ammonia is probably the single most dangerous chemical to your fish in a freshwater fish tank. Chlorine and chloramines are just as toxic, if not more so, but they are never produced in your tank, so if you eliminate them in the water you add to the tank before adding it, you don’t have to worry about them. Ammonia, however, can be added into your tank with fresh water, and it is also produced by any animals and decaying material in your tank. In fact, one huge source of ammonia for many tanks is the tap water itself. If your water supplier uses chloramines and not chlorine, even a dechlorinator that “neutralizes” chloramines can leave behind high levels of ammonia in your water. Most dechlorinators neutralize the chlorine part of the chloramines, yet leave the ammonia intact. This means you may be adding as much as 4 ppm or more ammonia in your freshly treated tap water. To avoid this you need a product such as Prime or Amquel or Amquel + that eliminate ammonia as well as chloramines. As discussed in the cycling section of this blog, ammonia in an established, healthy tank is consumed by bacteria as quickly as it is produced, but can be a serious problem for a cycling tank or if the biological filter fails. This is why ammonia should be one of the first things that you test for if you see any symptoms of disease or problems with your fish. Often, even if ammonia poisoning isn’t the direct cause of your fish’s illness, he has the illness because he was weakened by ammonia in the water. During cycling of course you need to test for ammonia regularly to know when the cycling is progressing to the next stage or is finished, and you need to test for it every couple days if you are using live fish to cycle the tank. Other times to test in a healthy tank are when adding fish, for the next week after a filter failure or power outage, or any time you think waste may be building up in your tank. One final note on ammonia test kits; you should avoid Nessler style test kits, such as Nutrafin’s NH3/NH4 test kit. With Nessler kits you cannot detect anything up to 1ppm of ammonia with any reliability. The indicator simply doesn’t change color enough to tell the difference between 0.6 and 0. These kits are characterized by a gradient of colors from clear to dark orange or amber, with the darker color meaning more ammonia. A better choice is a salicylate test kit, which has a gradient from yellow to green, with yellow being no ammonia and darker green meaning higher levels.

Nitrite is right behind ammonia in threat to your fish, and is appropriately the intermediate compound between ammonia and nitrate in the nitrogen cycle. Nitrite is of course quite toxic, though less so than ammonia. Since there are two entirely separate species of bacteria that convert ammonia ultimately into nitrate, you can conceivably have 0 ammonia, yet dangerous levels of nitrite if your biological filter fails. Any time you have reason to test for ammonia, you should test for nitrite as well. The causes of high nitrite are pretty much the same as for high ammonia, but you don’t need to be as alarmed about the nitrite as the ammonia, since ammonia is significantly more toxic to your fish. Test for nitrite when cycling your tank, when your fish get sick, or when you have an equipment failure, as for ammonia.

Nitrate is the last of the “nitrogen cycle compounds” that you should monitor. Nitrate is much less toxic than either nitrite or ammonia, but can still cause problems in your tank. This can be the case for any tank, as there are no bacteria that convert nitrate into less harmful substances. Plants can help by taking up some of the nitrate as nutrients, but the only effective way to eliminate nitrate from your tank is via water changes. However, depending on your water supply where you live, runoff of fertilizer into the local water supply can mean that nitrate is already present in your tap water. If you start getting high levels of nitrate and water changes do not reduce it, you may want to test your tap water for nitrate to see if it is coming from there. Since nitrate is so much less harmful than nitrite or ammonia, you don’t need to test for it very often, but since it is constantly building up in any tank that has fish in it, you do need to test for it regularly. Every 2 weeks to month is a good idea, depending on stocking level of your tank, and how many live plants you have. One thing to note about nitrate tests is that many convert nitrate into nitrite, then test for nitrite, rather than directly testing for nitrate. This is important if you have nitrite levels in your tank. Since you are not supposed to have any nitrite in your tank unless you are cycling it, this characteristic of nitrate test kits is not a problem, but you need to keep it in mind if you have nitrite in your tank. For example, if during cycling you measure 5 ppm nitrite with your nitrite test kit, and your nitrate test kit says you have 5 ppm nitrate, you may have no nitrate at all in your tank at this point; your nitrate test kit may just be measuring nitrite. Also, remember that hobbyist kits are not the most accurate in the world, so if your nitrite test kit says you have 2 ppm nitrite, and your nitrate kit says you have 5 ppm nitrate, you do not necessarily have 3 ppm nitrate, you still may have no nitrate if the 3 point spread is within the COMBINED margins of error of your test kits. The test kit you have may directly test for nitrate, and not nitrite, so you can’t assume that your readings of nitrate are being altered by nitrite levels in your tank. It is just something to keep in mind.

Acidity/basicity of your tank is measured in terms of pH. The pH of a tank is usually around 7, give or take a single pH point, though sometimes the pH can be as high as 9 or as low as 5. The higher the pH, the more basic the water, and the lower the pH, the more acidic the water. While all fish have certain pH ranges that they can live in, some a larger range than others, all fish are sensitive to dramatic changes in pH. Having a stable pH is more important to the health of your fish than having a certain “correct” pH. For example, you may have a fish that “should” be in a pH range of 6.5-7.5. Your water’s pH is a7.8. It is much better for your fish to live in the water at a steady level of 7.8 than to have the pH continually swinging from 7.8 down to 7.4 and back up the 7.8 over and over again as you try to adjust the pH of your tank. You do need to monitor your pH to make sure it is steady. Buildup of waste, limestone-containing stone or substrate and real driftwood in your tank can all alter the pH of your tank. Sometimes this alteration may be desired, such as adding limestone to increase your water hardness. However, you want your pH to stay as steady as possible, or your fish will become stressed and may die. pH should be tested every couple weeks or more often to make sure it is steady and not drifting on you.

Hardness is another common water parameter to test for, though it does not need to be monitored as regularly as the previously discussed parameters. You do need to know how hard your water is to know what type of fish you can keep, but you don’t really need to carefully monitor it for most fish species. There are two components to hardness of water, General Hardness (GH) which is generally talked about in terms of calcium hardness, and Carbonate Hardness (KH) which is also known as alkalinity (not to be confused with basicity). KH acts as a buffer in a fish aquarium, keeping the pH steady. If you have a problem with frequent pH swings, you may need to increase your KH to help buffer your tank. GH and KH are necessary for snails, as they build their shells out of the calcium and carbonate. Since the hardness of your water is fairly steady though, you do not usually need to worry about regular testing of your GH or KH unless you are trying to alter those values.

Chlorine is really not necessary to test for. The amount of chlorine or chloramines in your water (if you live in the United States) will not exceed 4 ppm by EPA regulations. As long as you use a dechlorinator that eliminates chlorine and chloramines, and use enough to eliminate 4 ppm in whatever water you add to your tank, you don’t need to worry about chlorine being in your tank. If you really want to know how much chlorine your water provider uses, or you want to make sure the bucket of water you left our overnight is really free of chlorine, you can of course buy one of the chlorine test kits, but I don’t personally see any need for one.

Copper test kits can be useful if you are using a copper-based treatment for parasites or illness in your tank, as the copper must be at a certain level to be effective, and if it gets too high it can become fatal. Homes with copper pipes also may have some copper in the water that has sat for any period of time in the copper pipes. If you don’t use copper for treatment of your fish though, there isn’t any real need to test for copper. If you are worried about it being in your pipes, simply run your water for 30 seconds to a minute to clear any copper-containing water out of your pipe before filling your bucket. If you have water quality issues that the common parameters, such as nitrogenous wastes and pH can’t explain, you may want to test for heavy metals like copper.

Iron test kits are similar to, though even less vital than, copper test kits. Municipal water supplies often contain trace iron amounts, though they are usually far below a toxic level to fish. If you have plants, iron is a necessary micronutrient as well. Unfortunately, algae also uses iron as a nutrient, so having iron in your water can speed up algae growth. One problem you should be on the lookout for is that rust from any lights or metallic equipment you have over your aquarium may fall into the water. If this happens, your iron level may grow to toxic levels very quickly. It is best to avoid having anything that can rust over uncovered water. In general though, iron is not a necessary water parameter to test for. As with copper, if you have issues in your tank and your water is free from the normal toxins, you may want to test for heavy metals.

Oxygen test kits are available for freshwater or saltwater aquariums, but in freshwater aquariums it is usually not vital to monitor your oxygen level. If you have healthy plants, or good filtration and/or bubblers in your tank, you don’t need to worry about the oxygen level in your tank. If you are worried, it is easier, and often cheaper to simply add some aquarium plants or a bubbler than to constantly monitor your oxygen level. If your level is too low, you will need to add one of those anyway, so in my opinion an oxygen test kit is pointless for a beginning freshwater aquarist.

Phosphate is the last chemical I will discuss that has test kits sold for it, though there are several others. Phosphate is a chemical that is produced as waste from decaying plant and animal matter, and is also present in a fish’s waste. Phosphate, unlike the nitrogenous wastes or heavy metals, is not likely to become toxic to your fish. Rather, like iron, phosphate greatly speeds up algae growth. Plants use phosphate as a fertilizer, yet in a normal tank there is far too much phosphate being added for the plants to absorb all of it. Water changes can keep your phosphate level under control, but unfortunately, in certain areas runoff of water from farmland can have fertilizer in it, so phosphate, like nitrate, can be added in this way to your tank during water changes. If you have a serious algae problem, you may want to test for phosphate to see if this is a problem, but in a freshwater tank it is not vital to test for phosphate.

Once you know your water parameters, you may be tempted to adjust them, either because the fish you want live in a different set of conditions than you have, or because you think your fish will do better with different conditions. There are many products out there that can adjust your water chemistry; from pH up and down to baking soda, there are tons of chemical supplements to alter your aquarium water. I would suggest you not use any of them. As noted earlier, it is much more harmful for a fish to be in constantly changing water than to adjust a less than “ideal” water quality. pH up and pH down do what they say they do, they push up or down the pH of your tank water, but they are very hard to use so that you keep the pH steady. These do not add the necessary buffering to your water, so while they do in fact push the pH up or down, those pH levels can change every easily. Unless you have experience with altering and maintaining a tank’s water chemistry, or you are willing to kill a lot of fish while you learn how tricky it can be, you should leave the pH where it is. The safest way to push the pH up would probably be to add crushed coral or limestone to your tank’s substrate or filter, or add driftwood to your tank to drive the pH down. This is not usually a good thing, but it is more gradual and safer for your fish than adding chemicals from bottles. Hardness is also increased by the addition of limestone or coral, and can also be increased using calcium carbonate (both KH and GH), calcium chloride (only GH) sodium bicarbonate, which is baking soda (only KH) or other products that are designed to increase a fish tank’s hardness. Again, it is often better for fish to live at “incorrect” hardness than to undergo drastic changes, but using limestone as a substrate is not likely to cause dangerous swings in the levels. For heavily planted tanks you may need to add micronutrients if you want the best possible growth. These can be expensive, and more importantly, it can be very hard to find fertilizer without the three MACROnutrients. Your plants get all the nitrate, potassium and phosphate they need from the fish food and waste from fish; they do not need more from fertilizer, and it can poison your fish. CO2 injection is one very common method of fertilizing your plants, and while it can be expensive to set up an injection system, you can make an effective do it yourself system for just a few dollars. In general though, while it is vital to test your water to maintain the quality your fish need to thrive, it is NOT a good idea to start pouring chemicals into your water.