How Do I Change The pH And/or Water Hardness Of My Water Tank?

It is highly recommended, although not absolutely essential, to test your water. The most common test is of the pH of the water. Test kits to measure pH are economical and easy to use. Hydrogen ion activity (known as pH) is a measure of how acidic or alkaline the water is. The pH scale goes from 0 to 14, with pH of 7 being neutral, pH less than 7 indicates acidic water, and pH greater than 7 indicates alkaline (also called basic) water. Some fish come from naturally alkaline waters, some from acidic ones, but nearly all are happy in water that is near neutral. While a pH of 7 is considered “ideal” most fish are happy at a pH of anywhere between 6.5 and 7.5. There is little point in trying to maintain a pH of 7.0 continuously, since pH varies depending on water chemistry and on the fish themselves. As mentioned before, new tap water is usually slightly alkaline, while fishes waste products tend to make the water more acidic. This means that, over time, pH in the aquarium will gradually drop. This is where the value of a pH test kit really lies. If you know that your source water is neutral to slightly alkaline, and your aquarium water has become acidic (dropping below 6.5), it is likely that there is a build up of other waste products as well, and that it is time for a water change. By regularly testing pH you can judge fairly accurately whether or not you are doing sufficient water changes. If you are, the pH of your aquarium should not drop too low, but will vary between being slightly acid and neutral to slightly alkaline. If the pH of your water stays low, or drops very quickly, it may be that you are not changing enough water, or that your aquarium is becoming overcrowded. If the pH of your water increases over time, you probably have some marble or limestone in your gravel or other decorations. Some fish do not mind this higher pH, but others will not like it. It is best to find the source of the problem and remove it. You can also test for the presence of other waste products directly, with kits available for testing ammonia, nitrite and nitrate. These are generally more expensive than pH test kits, and many have multiple reagents, but they do give a more complete picture of conditions within the aquarium. If you are having problems with unexplained fish deaths or cloudy, smelly water, it is a good idea to perform a test for ammonia. If you have overfed your fish, the uneaten food will rot and produce ammonia. Ammonia may also be a problem if too many fish are added to a newly set up aquarium (ie before filtration bacteria can be established), or if filtration bacteria have been killed off by highly chlorinated water, a medication, or a build up of solid waste product. If all is going well, then there should be no ammonia detectable. It is a good idea to check the ammonia, especially in a newly set up aquarium, to be sure the filtration is working and is adequate. If you find that there is continuously no ammonia, then you probably do not need to keep testing. However, keep an ammonia test kit on hand. If things do go wrong, it is the first thing you should check for. If you find a high level of ammonia in your water it is best to do a water change but do not clean your filtration media, unless this is choked with detritus that is causing the problem. In extreme cases, you can also add an ammonia remover or a dose of beneficial bacteria. Nitrite is produced by the breakdown of ammonia, and nitrite is then broken down to nitrate by filtration bacteria. Again, if all is going well, no nitrite will be detectable. If your filtration is not working, you will usually see ammonia first, but if you are having problems and no ammonia is present, then nitrite may be the culprit. Although less toxic than ammonia, nitrite is still capable of causing rapid, and seemingly unexplained fish deaths. Treatment for nitrite is similar to that for ammonia: change some of the water without disturbing the filter, and add a beneficial bacteria in severe cases. Nitrite-absorbing resins can be added to the filtration if nitrite is an on-going concern, or simply as an added safeguard. Nitrate is the final waste product, and although much less toxic than either ammonia or nitrate, it is still undesirable. Prolonged high nitrate levels are stressful for the fish, and nitrate also promotes algae growth. In most cases a low pH will indicate that nitrate is high, but where limestone and/or marble are present they will raise the pH, and in this case it cannot be used as a guide. In these cases nitrate should be tested for directly. If your regular water changes are sufficient nitrate should stay well below 100 ppm. To control algae, you may want to keep the level of nitrate even lower than this by doing larger or more frequent water changes. If nitrate stays high or increases rapidly, your aquarium may be becoming overcrowded. There are other things which you can test your water for, but these are not normally necessary. Other things you may want to test for are: Oxygen – while oxygen is clearly essential, it is not easy to test for. Shaking or agitating the water in any way will increase the oxygen content, making the test invalid. Electronic probles are available, but very expensive. If the water is chronically low in oxygen this will usually be obvious, since the fish will hang just under the water, gasping. In this case, change some of the water, and, if an airpump is available, add an airstone, or increase air flow to the aquarium. General water hardness – a measure of dissolved Calcium and Magnesium salts. As with pH, some fish come from naturally soft waters (low in dissolved salts), some from hard water (high in dissolved salts). Most fish you buy will be acclimatised to the hardness of your local water supply. If you are not using the same water as the store where you buy your fish, and especially if you are using bore water, rain water, or a mix of both, it is a very good idea to measure hardness. Try to get a mix of water that most closely resembles the water the fish are coming from, both in pH and hardness. The other time you may need to measure hardness is if you wish to breed certain fish species, particularly those which need soft water in which to breed (eg neon tetras), or if using copper sulphate to treat snails or disease, since this should not be used in very soft water. Carbonate hardness – a measure of the dissolved carbonate salts. Carbonate salts play a role in determining pH. If you find that the pH of your water is very stable, then it is proabably being “buffered” by the carbonates that are present. It may even be that your water stays slightly alkaline. This is usually nothing to worry about, in fact a stable pH is desirable. For this reason, a certain amount of carbonate hardness is a good thing, and you can measure it if you are interested, but it is usually sufficient to measure pH. Carbonate hardness should be measured if you plan to use CO2 fertilization of your plants, since it is highly desirable to have a moderate carbonate hardness to make this process most effective and to keep the pH stable as CO2 can otherwise cause pH to drop. Carbon dioxide (CO2). This should be tested for where CO2 fertilization is used. A balance must be found between providing enough CO2 for the plants, but not too much, which will suffocate the fish. Where CO2 fertilization is not used, it is not usually necessary to test for CO2. In this case, CO2 will only be too high if there is over-feeding or other decaying organic material in the tank. Accordingly, oxygen will be low, and the fish will show their distress by gasping at the surface. Phosphate is a waste product, often produced by uneaten food, that promotes algae growth. It is not toxic to fish, but if you are having problems with algae, you may wish to test for phosphate. If you are using a low quality fish food, it may be contributing large amounts of phosphate to your water. You may even wish to test your source water for phosphate. Iron is a nutrient needed for plant growth. If your plants are not doing well, you may wish to test for iron to determine whether this is lacking. If you are fertilizing plants, it is a good idea to check iron levels to determine that you are providing correct fertilization and not too much. Iron is also present in some water supplies and can be toxic in too high a concentration. Calcium is a mineral required by corals, testing calcium will ensure you are providing enough of this essential element in reef aquaria Copper is used in many medications and can be toxic to some species if the concentration becomes too high. If you keep sensitive species and want to use a copper based medication, you should test the copper concentration to be sure it does not exceed the desired dosage.

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