Question about Ozone Generators and Carbon Filters

Author: Scott  


Hello Scott

I am looking into some sort of solution to odour problems for hydroponics and I am becoming somewhat confused as to what is the best. Just wondering if you had any thoughts on ozone generators vs. active carbon filters vs. ionisers, or if maybe you could direct me to some good information on the issue. I have also read that you shouldn’t have a ozone generator in the grow room and that they need 1-2 minutes in contact with the air to be effective. This would require a rather complicated system with air being ducted into a separate chamber, left there for 1-2 minutes with the generator on and then being expelled. This sounds like it would be a pain in the arse to set up. Can you run a ozone generator in ducting with constantly flowing air? In this case would you need to run it constantly? Your thoughts on this matter would be greatly appreciated.


Yes, the odour issues are important to think about.

Carbon filters are expensive, and only clean the air you pass though them. They do work, so go for it if you like, but…

Typically attached to the exhaust fan, it ensures no smell goes out the exhaust, but the room still has smell, and this can slowly make the whole house smell, though the roof cavity, the hallways, and so on, until you can’t open the front door without the smell being obvious.

Ozone Generators have always been fairly simple for me.
You put them in the room with the plants (I don’t have much success with putting it into the inlet duct.)
You ALWAYS put them behind an oscillating/pedestal type fan so the Ozone is spread about, diluted and there is a good air movement through out the growing area. Ozone cannot build up at any place in the growroom, nor can any area escape the ozone being distributed.

You only need as much ozone as there is smell in the air. 15 minutes on 45 minutes off is usually enough to make the air free of smell, without removing the smell from the plants. Usually if the smell on the plant is reduced, it returns within an hour, hence the need to make small doses regularly.

As the smell and the ozone collide, both are destroyed by oxidation. If the ozone has nothing to react with, and there is enough of it, firstly, you will smell the heavy ozone smell, and then it will tickle your eyes and then your throat. If you expose yourself for longer you will get ozone into your chest, and may begin to cough, and you are being silly. If you still remain there with all these symptoms without switching off the unit, and ventilating the area and getting out, you will be damaged. Its not rocket science. Be careful, not paranoid.

While you are feeling these symptoms, you will notice the plants are not doing well, and if you don’t reduce the ozone the leaves will begin to get some brown splotches, and eventually become a big problem. Common sense means if you keep the ozone to a safe level, the plants will be fine also.

To summarise, I put a money back guarantee on my ozone units that if you follow instructions, it will do the job. You might need to move the unit until the distribution of ozone is effective, but generally, switch it onto the 15min cycles when the smell begins, reduce or increase the cycles if necessary but only slightly, and usually you will find it all works fine. Initial dose may be higher to reduce any initial smell build up.

Forget separate chambers, ducting, continual running, it all sounds stupid to me. The light of the unit can be a problem when the the growroom has its night cycle, and some black ducting with a s bend is a good idea, attach the duct to the back of the oscillating/pedestal fan – or don’t run it when the lights are off.

Nerang Hydroponic Centre 4/50 Spencer Road Nerang QLD 4211 Australia Phone (07) 5527 4155
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