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Water Filtration With Reverse Osmosis (RO)

Water quality can have a large influence on any hydroponic system. Knowing when to use a filtration system or even reverse osmosis is key to achieving great results in your grow.

Water Filtration With Reverse Osmosis (RO)

Water quality can have a large influence on any hydroponic system. Knowing when to use a filtration system or reverse osmosis is key to achieving great results in your grow.


Reverse Osmosis Filter

What's In My Water?

Most people wonder why they even need a water filtration system if they are able to water their houseplants with tap water. The short answer is, you many not. In the United States, tap water varies from 0.2 to 0.8 EC or higher. This means that there is quite a bit of variation. Often, nutrient solutions will instruct growers to feed young plants until the solution reaches some preset concentration such as 1.2 EC. This doesn’t sound hard until you realize that if your water isn’t at zero you have no way of knowing an accurate concentration level. Also, even though you may already know your waters EC level, you have no idea what dissolved solids are already in your water. This makes maintaining a healthy nutrient solution level in your water very difficult. Tap water can also vary EC by the time of day making an already difficult problem even harder. Hard water tends to coat the interiors of your hydroponic system with minerals and dilutes the efficiency of your grow. Some of these minerals are useful to your plants but they may be cancelling out the effects of the nutrients that you are adding at the concentration levels found in tap water.



One of the biggest issues with tap water is chlorine or chloramine often used to prevent bacterial growth in water systems. Chlorine will usually evaporate out of water if left for 24 hours but chloramine will not. Both can be removed with ultraviolet light. Both of these chemicals neutralize plant friendly bacteria such as mycorrhiza and trichoderma which are often added to improve root structure and nutrient uptake.




How Do I Find Out What's In My Water?

Public Water

If you get your water from a public or community water system, yearly reports are published on water quality. These are freely available to the public and can usually be found on your water utilities website or by calling your utility company. The EPA provides a list of phone numbers for water utility providers on their website. The Safe Drinking Water Act requires public drinking water to comply with certain EPA standards of quality. Figure 1 shows a portion of the 2015 report for the city of Anaheim California (click to enlarge image).

2015 Anaheim, CA Water Report Figure 1. 2015 Anaheim, CA Water Quality Report

There is a lot of data here but some of the takeaways would be the levels of calcium, magnesium, potassium, pH and water hardness. Knowing these will help you start to know what you need to filter in order to achieve optimal growth. This water is too high of pH for optimal plant growth with a pH between 7.6 and 8.1 and would need to have pH down added, especially for hydroponic gardens. This water would be considered particularly hard with CaCCO3 being between 264 ppm and 321 ppm for city and ground water respectively. Figure 2 shows water classifications based on mg/L and ppm concentrations. As a contract, freshwater usually ranges from 15 to 375 ppm and seawater is about 6630 ppm.

Water Hardness Figure 2. Water classification chart taken from Wikipedia.org

Water quality varies, even within city limits. Getting a quality water meter is a great start to testing your water and knowing what you are dealing with. Another option for those that are serious about water quality or considering getting a larger reverse osmosis system is to have Hydrobuilder test your specific water in order to build a custom water filtration system for your unique needs. Call us at 888-815-9763 or email [email protected] for more information on what we can do for you.


Well Water

If you get your water from a well, the only way to know the quality of your water is to have it tested. Well water is not subject to any of the filtration and purity standards that public water is and can vary widely from site to site. Contact us at 888-815-9763 or email [email protected] to have a test of your water conducted to know what you need to filter for and how we can improve your water quality.


Reverse Osmosis Filter

Reverse Osmosis (RO)

RO filters are one of the best ways to ensure that you are providing clean water to your plants. Many filters come with a three stage filter. The first stage removes fine particles and protects the osmosis membrane. The second removes chlorine and chloramine and other organic elements. The final stage removes the majority of dissolved solids and renders the water virtually pure.



Filter Membranes

Filter membranes are an important way you can improve your RO system. Many RO systems are compatible with a range of membranes depending on your needs. Base filters that come with the system usually are able to filter out sediment and chlorine. Upgrading your filter membrane to a carbon filter, kinetic degradation fluxion (KDF) / CAT filter, or ultraviolet sterilizer can greatly improve your water filtration system. These filters can remove many more contaminants found in all water supplies and sterilize them. Hydro Logic and Growonix are two companies that make upgrading filter membranes within their product line easy. Upgrading your membrane is one of the cheapest and easiest ways to significantly improve your RO water quality without having to change your entire filter system.



Once water has been filtered, it is important to remember to add back in the positive nutrients that might have been filtered out such as calcium and magnesium. Pure water also needs to be pH balanced in order to increase uptake from plants. These are very important steps in any garden and especially in a hydroponic, aeroponic, or nutrient film gardening system since they rely heavily on water for transport of nutrients and other dissolved compounds.


Booster Pump

Booster Pumps

RO water systems produce more water with additional water pressure. When water pressure is not enough to optimize your water filter, a booster pump can dramatically improve how much water a RO system delivers. Water pressure varies from house to house and older homes often suffer from poor water pressure due to calcium build up in water lines and valves over time. Hydro logic and Growonix make a range of booster pumps to fit inline before their water filtration systems in order to maximize their effectiveness.


What size do you need?

Filters range in how much water they deliver. For each gallon of water they deliver there can be two to three gallons of waste water that need to be disposed of so it’s important to size your filter correctly for what you need. Most filters are rated in gallons per day (GPD) or gallons per hour (GPH) delivery. Waste water has all the same sanitary qualities of potable tap water but with a slightly elevated concentration of minerals and water treatment chemicals. It is not recommended for direct human consumption but can be used for flush toilets, laundry, washing vehicles, decorative fountains and other uses that do not require as pure a water source. The temperature of water can have a big impact on how much water a RO system will produce per day. Warmer water tends to filter faster and provide more purified water over colder sources.


Commercial Solutions


Once you start needing over 2000 GPD you’ll want to talk to us about a custom filtration solution that would better meet your needs. We can find ways to custom tailor your filtration system to meet your specific water supply in order to make it more efficient and economical for you.



Give us a call at 888-815-9763 or email us at [email protected] to talk to a specialist about all your water filtration needs.