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3 Water Quality Issues You Could be Facing

Date: 01-05-2021

Poor water quality can be detrimental to the success of your system. Water that is too hard, too high in sodium or full of chlorine can negatively impact the health of your hydroponic setup. You might be thinking, 'tap water is clear and safe for me to drink, logically, it must be okay for my plants as well'. Although this is a common train of thought, it is simply not the case. Treated municipal water is in fact the most recurrent cause of problems for hydroponic (and aquaponic) growers.

The good news is that we're here to help, and we'll do that by running through each of these water quality issues, how to spot them and what to do if one of them is affecting you. 

Problem one: Your water is too hard

A 'hard' water supply is the most common of the water quality issues we will discuss today and is essentially water with high alkalinity. Hard water is most often seen when growers use a municipal water supply (tap water) in their system. This is because before tap water reaches you, it can travel through deposits of limestone, chalk or gypsum which are high in magnesium carbonates, bicarbonates and sulphur. It is important to remember that tap water varies from city to city, so the water from your faucet could be hard, or soft.

To find out whether your water is hard or not, test its pH. A high pH will indicate hard water in your system, you may notice white limescale build-up on surfaces and grow equipment which will indicate the need for a water change. If you can't see any of this build-up, a product like pH down will help to soften your water. 

Problem two: Your water is too soft

Unless your water supply has undergone distillation or a process of reverse osmosis, it will probably carry some salt content. Groundwater typically carries a higher salt content than other water sources, as the sodium leaches from surrounding soil into the water.

In some cities, municipal water supplies come from seawater, in this case, water desalination is used to separate salts and other minerals from the water, making it safe for you to drink. This form of municipal water is still toxic to your plants, as they are more sensitive to sodium than you are.

Another reason you might have water high in sodium is if you have previously had 'hard' water and have adjusted your pH or nutrient dosage to soften it.  Sodium chloride is not largely taken up by plants, which means it can accumulate in your system, which will end up displacing other elements and nutrients that your plants CAN uptake.

Water with high salt content is essentially the opposite of 'hard' water. From now on, we'll refer to it as 'soft' water. You can find out if your water is soft by testing your water's pH. If pH is low, the water is soft and should be adjusted with a product like pH Up. 

As the sodium in your water will build up over time, there are other ways to combat this problem. For low to moderate levels of sodium, growers may opt to avoid recirculating nutrient (as is the case with run to waste). Growers may also opt to grow vegetables like tomatoes which have a higher tolerance for sodium levels. If your sodium levels are beyond moderate, they could be toxic for your plants. If this is the case for you, you can dilute your water with a lower mineral water source, use a reverse osmosis treatment, add more pH Up to your system or use rainwater. 

Problem three: Your water contains water treatment chemicals

In most places worldwide, water safety regulations dictate the use of chemicals in treating municipal water supplies which make tap water safe for human consumption. Sometimes, this chemical is chlorine which is toxic to plants. If your water supply contains chlorine, best practice is to use rainwater, reverse osmosis or you can simply let it age for a couple of days before use. 

Although chlorine was once the most common way to treat large supplies of water, as technology evolves, many cities are switching to increasingly effective methods of water treatment, like the use of UV light, chloramines and chlorine dioxide. Chloramines, in particular, are just as harmful to plants as chlorine but are much more persistent and take far longer to dissipate from water. If your water supply contains chloramines, you can treat it with a dechlorinator or a water conditioner. You could also consider using coco coir as your growing medium, as it can help to deactivate some of the treatment chemicals in your water supply. 

If you're concerned about your municipal water quality, you can obtain a water analysis report. Your local water supplier should be able to provide you with a full water report that details exactly what minerals and treatment additives are present in your supply. 

For those using ground, river or dam water, you can send a sample off for lab testing. If you want to get your water tested, but you're not sure where to start, give us a call and we'll put you through to our best contact. 

Best of luck, and happy watering!