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Completely useless research of Dissolved Oxygen Concentrations


Well-Known Member
This bit of research was done for a new member who wanted to know the "safe range" of oxygen concentration in hydroponics given as a percentage. Turned out to be a waste of time but I thought I'd share it with everybody so you can waste time reading my useless findings. Feel free to trash my results.

In order to discuss this we have to accept some generalities as there is no definitive study on the LC50 of low levels of dissolved oxygen in hydroponically grown cannabis. Believe me, I tried finding something, anything, scientifically definitive. Therefore, the following is an extrapolation of information.

Generally, hydroponically grown cannabis is grown in solution temperatures ranging from 15.5C to 24C. Empirical evidence indicates that 18C is optimal.

Numerous scientific studies indicate that at DO concentrations of less than 3ppm many aquatic life forms begin to show degradation of viability, and that the LC50 for these organisms is in the range of 1.5ppm. If we want to establish a "safe range" below which we do not want our oxygen levels to drop then we can posit that we should keep the DO above 3ppm. I created this nomograph to help understand this (useless) information.

It follows then that the "safe range" for dissolved oxygen is generally above 30 to 35 percent saturation dependent upon temperature.

We don't EVEN want to get into how the presence of dissolved solids affects oxygen saturation!

And no, I didn't copy and paste this! This shit is from my own efforts in answering your question, JP23. I hope it helps! (note: it didn't :))


Well-Known Member
Hey JustMeds! I wasn't ignoring you! I've been on a hiatus and just got back to the forums a couple of days ago. Not that I'll be much help, but I'm curious to see how your grow is going and how you're getting oxygen to the roots without airstones. This bit of research was done in response to what I thought was a serious forum member's question about dissolved oxygen. It turns out that the member had an ulterior motive and really had no scientific interest in the answer. Huge waste of time! LOL
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