Sure, you also need light and food for your plants and fish, but water, the water in aquaponics, is the lifeblood of your system. Most of your aquaponics problems will be caused by poor water quality. Therefore, it is vital that you keep your water quality as high as possible. There are several water quality factors that you need to control. Let’s start with what I call the 3 Hs: pH, GH, and KH.

Start with good water.

It is much easier to maintain good water quality if you start with good quality water. If the tap water in your home is not as good as it should be, you may want to have water delivered if it is available in your area. of course, you must test that water before adding it to your tank.

If you have the time and patience, you can run the water through a reverse osmosis (ro) filter to remove all the bad stuff. If you have a large system and a small capacity reverse osmosis filter, this can take days instead of hours. What to do if you have to start with bad water!

Adjust the pH

The pH of the water is expressed as a number that reflects the acidity or alkalinity of the water. The number can vary from 0 to 14, with pure water being 7.0, which is considered neutral. Technically, pH is a measure of the hydrogen ions in water. The p comes from a German word “potenz” or power. The H stands for hydrogen. H is capitalized because it is customary to capitalize element symbols. But enough chemistry, what we need to know is what pH number we are looking for and what to do if our water reaches that number.

Fish can survive in a fairly wide pH range, but plants are a bit more demanding. For most of us, a pH range of 7.0 to 7.5 is a good compromise. If your water tests are outside of that range, you can add products to raise or lower the pH until you reach the correct number. You should do this slowly, over a period of days, if you have already added fish. When you reach the target range, you can maintain it by adding a pH buffer. If you add a tampon, make sure it is safe for both plants and fish.

Tap water in most cities will be 8.0 or higher. This is done to reduce the risk of filtering harmful particles from the water pipes. Think of Flint, Michigan. The tap water in my hometown, Las Vegas, Nevada, is between 8.2 and 8.4. It took me several days to adjust it to the pH I wanted.

Products to increase or decrease the pH are available at most pet stores, hydroponics stores, or online at Amazon. You will also find kits to test the pH in these places. You can use test strips, test kits, or test meters. Kits and strips may not be as accurate as a test meter. Test meters are not that expensive, so you may want to invest in one of these.

Adjust for hardness

Tap water in Las Vegas rates as “very hard. I think it’s so hard that if you look closely, you can see little rocks floating in it. When I first tried to measure hardness with a witch test kit, you keep adding and counting drops in a test tube until the test solution changes color, the number of drops went up so much that I stopped counting and concluded that yes, the water was hard.

There are two types of water hardness: general hardness (GH) and carbonate hardness (KH). General hardness (GH) is usually a measure of the calcium and magnesium ions in the water. Overall hardness is not usually a concern, except that it can leave unwanted mineral deposits in faucets, bathtubs, and toilets. But your fish and plants need these minerals for good health.

Carbonate hardness (KH) is the measure of bicarbonate and carbonate ions in water. The important factor of GH is the effect it has on the pH of the water. Too high, it will be difficult to lower the pH, too low and the pH can undergo big changes that can be harmful to your fish. So we need it to be the correct one, a reading between 4 and 12 dKH that you can measure with an API test kit.

Other water quality problems

Temperature, levels of ammonia, nitrites, nitrates, and dissolved oxygen are also very important in maintaining good water quality. We will cover them in other articles. However, if you get all of your H’s correct up front, you will have an advantage in maintaining good water quality in your aquaponics system.