Hydroponics Water Filtration: Filter or Falter!

water filters

Well, that’s it folks, be sure to give this article a like, thumbs up…. Oh!  Oops!  I have everything in REVERSE for today’s article!  Read on to see why.

Many hydroponics systems’ guides advise using hydroponics water filtration to keep your plants happy.  If you’ve been using your tap water to drink, without filtering it, or spraying it on your garden plants and neither you nor the plants have kicked the bucket yet then you might be wondering what all of the fuss is about.

Today, let’s take a look at what the fuss really is about, how to figure out if your hydroponics system might benefit from water filtration, the most common hydroponics water filtration method, and some advice for setting up your system when including hydroponics water filtration.



What’s Wrong with Tap?

Tap Water
Bad Tap Water, Source


If you’re one of the two-thirds of Americans that don’t drink tap water then you probably don’t need so much convincing on this point (Go right on down to “Is My Water Hard?” and save yourself some time!) but the rest of us skeptics should read on:

I bathe in tap water.  I give my dog and cat tap water.  I make both my tea and my coffee with tap water.  Not only did I cook my quinoa in tap water this afternoon, but I also hungrily waited for that tap water to get soaked up into the quinoa before eating it.  I’m not going to invest in hydroponics water filtration if I’m not going to invest in human water filtration!  Tap water deniers (outside of Flint, Michigan!) are just finicky!

Yet again, what is good for us isn’t always good for hydroponically grown plants.  Your water may be too “hard” for your plants and as a result, won’t be able to properly deliver the nutrients you want them to get.  Yes, you read that correctly.  The water-bed filling we all know as water can be “hard” even above 32 degrees Fahrenheit.  Water hardness, explained in more detail below, is the main reason you might consider using a hydroponics water filtration unit.

When your unfiltered water is “hard” it has too many minerals in it.  These minerals make it more difficult for your nutrient mixes to properly take up the proper concentration of your water.  It is said that up to 85% of all US homes have hard water, so it is time to ask yourself a very important question:



Is My Water Hard?

Water Molecule
Water Molecule, Source


There are many ways that you might be able to guess if your water is hard, including scale growing inside your kettle just a bit too fast.  Americans can also check out this map to see the likelihood of the water being hard in their area, but before anyone goes out and gets a hydroponics water filtration system just for their plants (hard water is safe and possibly even healthy for humans) they’ll probably really want to be certain that this is actually an issue.

Fortunately, test strips are cheap and come in large enough bundles that you should be able to test your whole hydroponics club for under ten bucks.  Much like a pH test strip, you’ll be able to ascertain roughly how hard your water is by matching a reacting color to the colors of a chart.



What is Reverse Osmosis?

Hydroponics Water Filtration, Reverse Osmosis System
Hydroponics Water Filtration Reverse Osmosis System, Source


Alright, you’ve figured out that you have hard water.  Now it is time to get the actual hydroponics water filtration system.  A quick Google search will tell you that you probably want to get what is known as a “Reverse Osmosis” filter.  To figure out what that means exactly let’s break it down into digestible parts:


What is Osmosis?

Something about Mondays makes the average student want to rest their heads on textbooks and not their eyes.  At some point, the teacher is likely to crack a joke at the poor, sleep-deprived student’s expense that goes something like this:  “What are you trying to do, learn this through osmosis?”  The joke, like most jokes targeting students, wasn’t funny, but it did teach the concept of osmosis quite well.  Osmosis is a PASSIVE process (you putting in ZERO effort) of moving a HIGHLY concentrated thing (the KNOWLEDGE in the textbook) to a place with a LOW concentration of it (Your dumbhead!).

Your hydroponics water filtration system won’t be so lucky though.  It is going to take real effort to make it work!  This is where the word ‘reverse’ comes into play:



Assuming you were awake for the day the class learned the word ‘reverse’ then you’ve probably got it figured out what this means, vaguely.  Since reverse osmosis isn’t relying on the simple powers of a natural system like regular osmosis it is not passive – energy must be spent to get it going.  Reverse osmosis takes something that is in a low concentration in one space and moves it to a place of high concentration elsewhere.

What this all means for your water is that reverse osmosis filters are able to take the low concentration minerals that are making your water hard (even the hardest of hard water is measured in ppm – that’s parts per million) and remove them.  Then, aided by your hydroponics water filtration system, you’re free to add in the precise concoction of minerals that you actually want in the water manually.



What About Softened Water?

Alright, so we’ve established that water that’s not ice can be “hard” and that we don’t want hard water in our hydroponics systems, right?  Water that’s not hard must be called… softened water… right?  Well… not exactly!

Water that has undergone reverse osmosis in a proper unit made for hydroponics water filtration has simply reduced the hardness, not been “softened.”  Without going into such a level of detail as to leave you completely confused, let’s just sum it up with this:  water that is labeled as softened or water treated with water softening salt is usually too salty for your plants.

Quick take:  Don’t be fooled!  This is not how hydroponics water filtration should be done!


The Final Word

Today, we’ve covered the basics of hydroponics water filtration.  There is truly a dizzying amount of chemistry behind it all, but you don’t have to understand it all at this moment to evaluate if a water filtration device might be part of an effective plan to improve the health of your plants.



Picture of Grammy


I'm Grammy to my grandkids and most of the authors here. My gardening career started when I was a child digging and planting in my neighbors garden in Florida. As a teenager I worked on one of the first organic farms and learned the many benefits of organic farming. As a young Mom I started dabbling in hydroponics and became hooked! My family and I learned from research and "Hard school of Knocks " ways to improve our crop growing techniques which I am willing to share with you.