DWC Design Improvement?

This is a pretty difficult subject to search ( I've DEF tried), so if it's already been discussed and buried, a link would be helpful. Thanks.

Do you mean, put air through a mister?

I've used expensive Boss Hog diffusers and compared to good airstones, I see no difference. Maybe smaller bubbles are better, but it's having enough that is important.

Air stones work more then adequate for a properly maintained reservoir and the plants roots, most people who are looking for other ways have issues other then the "stones" they need to address. Just saying. I have had air hoses unplugged for 24-48 hours and the plants roots were fine.

Nothing you do will get your DO much above 8ppm, but that is enough, considering anaerobic pathogens have a hard time living in anything above 6ppm. The DO in the water itself will never be enough to support a plant in high production, which is why we leave a little air pocket between the netcup and the waterline, and why we want lots of bubbles making momentary contact with roots.

The amount of O2 dissolved in the solution will vary depending on both temperature and pressure. The warmer the water the lower the gaseous content will be. Really cold fresh water has a DO reading of up to 14 ppm or 14mg/litre, while water at 30 degrees centigrade can only hold about 5ppm or 5 mg/l DO.


This DO only amounts to a very small percentage of the roots needs. All water culture systems have to utilise some other form of oxygenation for the roots as well as DO in the nutrient. Root systems that have insufficient O2 available will soon turn brown and become very sick.


We aerate the nutrient in our systems in order to get the best saturation that we can, (from 5ppm to 8ppm) but the main function of this aeration is to kill off the anaerobic bacteria around the roots. Anaerobic bacteria are pathogens that cannot survive in an oxygenated environment; (Anaerobic meaning without air).


Because the DO in the nutrient can only supply about 1% of the roots requirements, the balance must be made up by breathing air. This air is trapped within the soil in conventional gardening and in the growing medium in normal hydroponics systems. This O2 search uses up energy that the plant could better use to produce root growth.

The limitation of hydroponics is the fact that 1 kg of water can only hold 8 mg of air, no matter whether aerators are utilized or not.

Quantitative Airstone Test. an end to the hype


http://en.wikipedia.org/wiki/Aeroponics
http://hydroponics-gardening-informa...om/Oxygen.html

Originally Posted by Hugo Phurst

Do you mean, put air through a mister?

Yeah, according to the copious amount of reading I've done, the smaller and more plentiful the bubbles are, the better it is for DO. i figured misters would put out ALOT of very small bubbles.

Originally Posted by jazzyjsd18

We also know the finer the bubbles, the better right?

No, we don't.

Originally Posted by Heisenberg

Nothing you do will get your DO much above 8ppm
Quantitative Airstone Test. an end to the hype
http://en.wikipedia.org/wiki/Aeroponics
http://hydroponics-gardening-informa...om/Oxygen.html

Nailed it. DO is not the only goal, total oxygen presence is much higher than just that of the oxygen actually dissolved. Aeroponics don't need high DO like DWC because air doesn't need to be dissolved to benefit the plant. DO has it's limits(gas laws) but you can still bring more oxygen to the plant. Less restrictive airflow(not diffusers) and bigger pumps are the answer, not smaller bubbles.