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March 5, 2013 Grow Guru Horticulture (info)

Why you should use Reverse Osmosis Water for Hydroponics

You may wonder why you should use reverse osmosis water for growing plants using a hydroponic method?

The sad fact that most water is polluted with chloramines, heavy metals, harmful bacteria and other contaminants. Some water comes with onboard magnesium and/or calcium, and this might be useful for your hydroponics plants. But most water just isn’t pure enough for you to grow successful crops and maintain plant strength.

We recommend you use a reverse osmosis system to clean your water for your hydroponic plants. If you use a quality reverse osmosis (RO) unit, like a 5-Stage Filter for example, you get water 98-99% free of impurities. Generally with a EC reading of 0.0, you get a neutral canvas or clean slate on which to “paint” your hydroponics nutrients so you know exactly what your plants are getting and when they get it. Giving you total control and peace of mind that your plants are at your command.

Should you not want to buy and install a unit, your local water store will be able to give you fresh clean water on tap at least 6 days a week.

Ironically, when you filter your water using a reverse osmosis system you remove trace elements such as calcium and/or magnesium. Most hydroponics nutrients manufacturers have even accommodated the pervasive presence of these two elements in source water by under-providing calcium and magnesium in their nutrients. Generally when you use RO water, just use a bit of General Hydroponics Mineral Magic for example, or a Calcium-Magnesium supplement. This stabilizes the water, helps your pH meter read the water better, and adds back minerals that you removed using RO.

Have you got better reasons for us? Feel free to leave you comments below.

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Filed in: Grow Tips, reverse osmosis water for hydroponics, why use reverse osmosis water
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Comments

Herz - January 27, 2020

Hey i use osmosis water because my tap water is way too hard. But i still have problems and try to fix what is going wrong. In the vegetative stage the plants looking healthy. I let the osmosis water stand for a day but in flowering stage i have to use the osmosis water right after i collected it in a bucket. And there the problem starts from weird leaf symptoms like a deficiency and they die after some days. It slowly works its way up and i can’t dix it. I did many tests with different nutrient strengths, different watering techniques, light distances and all i tried didn’t work.

So it must be the water source because in the vegetative stage if i let the water stand for an day the plants lookin great and in the flower stage i don’t have enough osmosis water for a day so i have to use it right after i collected it.

I measured the ph of the osmosis water that stand for one day and the ph is around 7to8 depending on how long it stands. The fresh osmosis water has an ph of 6. So im not sure if something gets out of the fresh water and changing the ph.
I also noticed that the nutrient solution falls out and smells bad if i take the fresh osmosis water but i didn’t test it with osmosis water that had stand for a day but i will test that the next days.

Could it be that there’s dioxide in the fresh osmosis water that needs to “bubble out”? I thought if the nutrients falling out of solution something must interact with the nutrients and oxides could lead maybe to those problems but im not sure and can’t find any informations. Or has the osmosis water not enough oxygen and the water that stands for an day will be more oxygenated because it takes oxygen out of the air? Im trying to find some websites that can explain what happens to the water 🤔 or only find some information how to work with osmosis water and to let it stand or if its not necessary.
Hope you know something about osmosis water and how you work with the water and if you oet it stand or use it right after you have the needed amount to water the plants with.

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