Tests aquarium water for carbonate hardness (KH) or calcium
This test kit includes everything you need to measure the general and carbonate hardness of your aquarium water.
To test our water, we brewers can use water test kits available for aquarium owners. The kind of test kit we need is one that tests GH and KH. GH stands for General Hardness and measures the total hardness of the water. In water speak the total hardness is the amount of calcium and magnesium ions present. It is commonly measured as either dH (German Hardness) or "ppm as CaCO3". Both these units are equivalent measures. That means that they don't express the weight of the calcium and the magnesium ions but their number per unit of volume. With knowledge of their atomic weight and an guess on the calcium to magnesium ratio commonly found in water one can estimate the calcium and magnesium content of the analyzed water [DeLange].
Though all freshwater aquarium owners should monitor water hardness it rarely happens in most homes. This is because of the need testing equipment. For some the cost of an electronic general hardness meter will be more than the cost of the aquarium. Chemical tests are also available that are not as expensive.
Water Hardness Test Kits & Strips for Aquariums | PetSmart
Get a reliable aquarium water hardness test
General Hardness is basically calcium and magnesium mineral levels. Plants and fish need both to survive! (hence you cannot use straight R/O water in your aquarium) In terms of German degrees I prefer to see it at 6-12 GH (multiply by 17.9 for ppm's), and again other values up or down will work. By achieving an 6 - 12 GH you will provide enough hardness minerals to benefit plants like Echinodorus (sword plants), and yet not be too hard to accomodate other softer water loving species. We maintain GH at 10 in the nursery. (remember when you top off evaporated water in your aquarium you must do it with R/O or distilled water, not tap water as you would be increasing the GH with tap water) Nitrate or ammonium (this is the pre nitrate form that fish provide by their waste, urine, and is preferred form) is a macro that aquarium plants need. How do we achieve a level of nitrate or ammonium in the aquarium? By providing an adequate fish population and regular feeding to insure those levels are maintained. You can also supplement with additives like Seachem's liquid nitrogen if you find it difficult to achieve those levels with your fish population and feeding schedule. We like to see a range of 5 - 10 mg/l of nitrate in the aquarium to have a ratio of 10 - 1 nitrate to phosphate, all the way to 20 - 1 nitrate to phosphate. We maintain a level of approximately 10 - 1 or 5 mg/l of nitrate, our phosphate levels being .5 mg/l that is explained below in the phosphate column. If you allow the nitrate level to go to zero, algae can then take the existing phosphate and begin to grow in your aquarium (plants need every macro and micro nutrient to continue growing, if one macro or micro is missing then plants will slow and stop growth eventually).Phosphate is a macro that aquarium plants need. How do we achieve an adequate level of phosphate in the aquarium? By feeding our fish the fish food provides the phosphates to insure those levels are maintained. You can also supplement with additives like Seachem's liquid phosphate if you find it difficult to achieve those levels with feeding your fish population and feeding schedule. We like to see a range of .3 - .5 mg/l of phosphate in the aquarium to have a minimum ratio of 10 - 1 nitrate to phosphate, if phosphate is .5 mg/l then nitrate would be 5 mg/l to achieve that 10 - 1 minimum. You can also have too much phosphate due to tap water that contains phosphate or overfeeding your fish which can then be corrected by using a phosphate sponge or water changes. This kit is our own planted aquarium master test kit and includes all of the above test kits at a discount over buying them individually!
Aquarium water hardness is a part of the aquarium water chemistry that is often not fully understood. In all, it is not that complicated. Fish tank water hardness is measured in degrees of hardness. Many home aquarium water test kits will give you measurements in either Degrees of Hardness (dh) or in parts per million (ppm).