UVC Safety

Hello there,

I’ve been lurking around the forum for a minute now but finally got around to joining. I have learned so much from this community and I really appreciate all of the knowledge you all contribute. I hope to some day return the favor and help this community level up.

I recently came across a discussion on using uvc light bulbs between cycles to clean rooms or in a light box for air intake to kill mold etc. before the air gets to the grow room. This is a great idea and I may give it a try soon.

One thing I was wondering is how this could apply to reservoirs. I have heard people on here say they use UV inline after RO filters to purify water during filtering, which seems ideal for clean starting water. I found some UVC bulbs designed for fish tanks and I was wondering if using UVC inside a reservoir is a bad idea. Would the UV light cause any issues in the nutrient balance or cause anything to drop out or bind in strange ways? I know it could deteriorate materials like the reservoir walls, but is that a short term concern? This bulb creates a small amount of ozone while lit, would ozone mess with the nutrients? Ph?

Previously I would use very small amounts of sodium hypochlorite to kill off any bad stuff before mixing a rez, and then add even smaller amounts every few days. This was one of the only ways I successfully fought off a murky rez since my rez lasts 4-7 days. If UVC doesn’t affect the nutrient ratios it may be a great way to steer clear of harsher chemical solutions. All in all I am trying to occasionally feed organics and bennies directly to pots while having a rez auto feeding (close to the multi-shot crop steering method). So my rez won’t have any organics or bennies in it, but it should also not have anything that could harm bennies in the medium too. Hence exploring UVC in a reservoir…

I didn’t see any answers to my questions on here so I decided to make a post. Let me know what you think or if you have tried this.

Bump. Anyone have experience with this?

I made a UVC light bulb air purifier. I’m not sure how much good it does. It does not get rid of pm.

I did notice in reading about light safety, the general rule is that uvc light does not bounce, or at least the dangerous part of the light. However, like everything else, there may be exceptions. There is some research to indicate that uvc will bounce off certain polished metal surfaces.

I have also run uv purifiers for a hydro reservoir long ago. It did not get rid of pythium, but I did not have any strange nutrient lockouts.

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Yeah, not expecting 100% purifying from the bulbs but they are cheap and if it helps a little it’s worth it. The aquarium bulb I got for my rez is 13w and probably overkill, maybe that extra power will do the trick. I secured it next to my mixing pump so it should cycle the whole volume past the light.

You need exposure of hours for UV to be effective. If you are attempting to sanitize something inline you will need to meet a high dwell time, or loop it in a reactor.

I use UVA/B/C directly over my canopy. I use UV at or above 10% total wattage.

I have a 55 gallon feed tank that circulates through a UVC reactor for hours before it hits the drippers. And I will still get some blue algea in my tables.

I’m a chemistry guy and my green thumb is black I can kill plastic plants that’s how bad my gardening abilities are… But about 14 years ago I had a grow house in partnership with someone that really knew his shit and if I remember correctly he used to throw in some hydrogen peroxide into the reservoir. It seemed to have done the job pretty good and he said it also helped providing oxygen to the roots.

UC Roots is the classical tek

Been in the specialised lighting business for 28 years.

UVC been around a long time and very very effective.

I use RO water that goes through 2 x inline UVC fittings.

1 Tap - inline UVC - water reservoir
2 Water reservoir - RDWC epicentre

So water going into RDWC should be 99.99% ‘‘clean’’

But, it also means that any pathogens may lie in the pipes running from the reservoir to the RDWC epicentre.

I did have an inline UVC unit on the RDWC return to the epicentre gut was advised that it can interfere with nutrient solution, especially Fe.

One way around this problem is to have the UVC on a timer so maybe on for 10-15 mins per hour.

I didn’t want to take that chance so use hypochlorous acid (UC Roots is one) in the RDWC - keeps roots nice and healthy.

Using a handheld UVC light to disinfect a growroom is perfect. Just protect your eyes, UVC cannot go through normal glass or plastic so wear glasses.

Read ‘’ Disinfection of nutrient solutions in recirculating hydroponic systems’’ on the Science in Hydroponics website.

Dr. Daniel Fernandez runs a great site :+1: :+1: :+1: