Some say DO in DWC – RDWC is important, needs testing like pH and EC

[B3henry]

How many of you DWC, RDWC cannabis growers test your reservoir nutrient dissolved oxygen (DO) with a thermometer to see how much or how little oxygen is actually dissolved is in the water?

 

[samarta]

Excuse my ignorance, but how is that measured. Right now all I know is that if I keep the water as cool as I can without retarding growth and generate maximum bubbles, I should be getting maximum benefit.

 

[B3henry]

Excused… no problem.
Just wondering… in your opinion, why do you chill reservoir water and who told you that? And, at what temperature does cold water (hypothermia) begin to suppress root and beneficial microbe metabolism? Hypothermia definitely compromises and retards metabolism guaranteed to slow root and Benny growth. Why would you want to do that?
This is the cheapest way to I have found to test and measure DO. Each DO test only cost about $0.50 - *Salifert Dissolved Oxygen Test Kit – $22.31 + ***FREE SHIPPING -- https://www.amazon.com/dp/B001EJ3DQ4/?tag=skimlinks_replacement-20

EC and pH testing is popular, cheap and common for DWC growers and most people know what to do if these test results are not within the “safe range.” Most growers react and implement corrective measures to get pH and EC back within the “safe range.” That is logical, ya.
But, what in the world would you do if you did a $0.50 DO test on your nutrient water and discovered that your DO saturation was not even close to 100% saturation and was only 50% - 60% DO saturated? Your water is cold and your air pump and bubblers are making millions of bubbles. This is far from the ideal 100% saturation which is considered “safe oxygenation?” What DO is do you considered unsafe or “low dissolved oxygen” conditions?
Would you do anything or just wait and tither about looking into the crystal ball and know what’s coming? Doing nothing about correcting a low DO back to the “safe DO range” is not even close to logical, but that is always the growers choice and responsibility to keep his crop healthy.
I have also heard that ignorance can be bliss. Sometimes it’s less stressful not to know what’s coming next when you know your nutrient DO is deadly low. Like knowing how long you have left to live and getting past denial to acceptance.

 

[samarta]

Warm water equals slime and root rot. Now that's ignorance. Above 70 and that what you get. Below 60 and my babes seem to slow. Healthy?? What do you think. You know you can get too technical with anything except rock science and this just isn't!

View attachment HPIM1182.jpg

View attachment HPIM1183.jpg

View attachment HPIM1184.jpg

 

[zem]

There are DO meters on the market that operate like the ph meters. I think that most growers who grow for personal use do not buy it because it is not a requirement and they can go without it and it is one less tool to buy one less thing to worry about. We know that as long as the temperatures are within an acceptable range, the roots seem to do well. Commercial growers of cannabis do not choose DWC in the first place. Big scale vegetable deep water culture like lettuce farms test their DO continuously. But that is a totally different application where DO testing is required.

 

[B3henry]

Commercial growers of cannabis do not choose DWC in the first place.

I have wondered how that really works. In your opinion, how do commercial growers grow cannabis on a production scale if they do not use DWC or RDWC hydroponic techniques? Are they simply dirt farmers growing in dirt, apply for and buy a State permit/license to grow and sell cannabis commercially?

 

[zem]

commercial marijuana farmers normally use a medium like coco, perlite hydroton dirt... They do that to not have to maintain a lot of airpumps and airstones and equipment when they can do great without that

 

[B3henry]

commercial marijuana farmers normally use a medium like coco, perlite hydroton dirt... They do that to not have to maintain a lot of airpumps and airstones and equipment when they can do great without that

Well, that‘s a no brainer, a eureka moment; high profits, extremely low production cost, minimal equipment cost = much more cash in offshore banks or buried in mason jars in the back yard… times are really good in America for growing cannabis (medical) commercially in many states. I would guess vast amounts of cash are made with the new canna-industry opening up in many states.
Why in the world any sober, rational grower ever consider grow hydroponically with all those complications and problems? You are saying the commercial grower would have no good reason for hydroponic aggravations and additional wasteful cost. I can see a clear difference between the pro and the immature hobby experimenter trying time after time to make his hobby hydroponic rig work.
Thanks for sharing Bro Knowledge

 

[zem]

Well in fact most of the commercial growers use hydroponic media when they are growing indoors. This is still hydroponics. Growing in dirt indoors is also a fuss for large scale ops since they have to haul in soil with all the diseases that accompany it and the lack of control over growing in it. On the other hand hydroponic media can be recycled and sterilised, light weight easy to move, clean, can control the feeding in it, etc...

 

[Hushpuppy]

The grow style (soil, hydro, etc) really depends on the person and how they like to work things. I have grown in soil and I have grown in DWC. I found that growing in my own modified RDWC is my favorite way. I can control everything that goes into the plant. With soil its more difficult for me as I don't know whats in the soil. And I have to maintain the microbe herd. With my method and nute brand, if I maintain the pH, TDS, and temps (water close to 68f and air around 72-75f) my plants are quite happy and healthy right up until harvest. I do run air pumps in my system. When I maintain that 68f (66-69f) I have no issues with DO or pathogens. I don't see the need to follow the DO too close as long as I maintain these other factors