CO2Meter RAD-0501 Day Night CO2 Monitor and Controller for Greenhouses, Grey

10 stars! I can't believe this unit can be this great of a deal, but it really does seem to be. Just got it, and out of the box it's completely accurate (within margins of all the meters in general), and is working perfectly so far. It was professionally packaged for shipment and doesn't feel like a cheap unit. If the build quality stands up and this unit lasts, it's going to be among the best purchases of mine to date. Edit: Unit is still working perfectly, and has doubled the life of my Co2 tank versus just using a regulator and timer. Only having to go once a month for refills now, means this unit will pay for itself in about 8 months factoring the costs of the Co2 and the gas driving. Update: It's been about 4 months since purchase and the unit is still working without any issues. I couldn't be happier at this point, and would buy another one without worry. I'll try and update towards the year mark, or sooner if there is an issue, which I don't foresee. 2+ Years update - Still working just fine. Getting ready to purchase another unit for another room and figured I'd update with news of the longevity. 3+ Years Update - Just as good as the day I bought them. 4 Years Update - The only problem I have had is that these are not in stock so I can't buy another one...

Works great. Always wondered what my PPM levels were without CO2 supplementation. Well, starts around 600 PPM and dips below 400 PPM. Now I have this I can not only monitor my levels but I added a 20lb CO2 tank of course. I keep my levels at 1100 PPM and since I bought this it has been 3 weeks. I have seen a major change in my plants growth. Girth has increased and I have needed to up my room temperature from 75F to 80F and nutrients from 0.6 EC to 0.9EC . I noticed a 200 PPM drop in my nutrient solution over a 2 day period. Usually I only see drops like this over a week period and when in transition (ie: week 2 of flower). Update: the newer model has a high and low setting. I got the newer one when I ordered another one a year later. Update: Since using this meter I have been able to monitor my CO2 supplementation and loss. It has been a money saver. My rooms are sealed now and I can get a 20lb bottle to last 2-3 weeks at 1200ppm. I have doubled my yield after tweaking my nutrients to coincide with the increased metabolism from my CO2 supplementation. $13 worth of CO2 every 2 weeks. Best $78 per grow spent ever. No bottled nutrient will give you the results CO2 will.

This meter was purchased to run my autopilot co2 generator. And I will tell you it exceeds my expectations. It's accurate and keeps my 18x90 greenhouse @ 1200 ppm. The meter can be used to run a generator or an exhaust fan to keep co2 from reaching high levels. Very easy to setup and use. 10 minutes and I was up and running. I'm going to purchase more for my other greenhouses and would highly recommend this to anyone needing to add co2 and precisely control it for a small grow to a large grow. A PLUS

The unit works well wish it had a longer cord,thought it had a co2 sensor on a cord not 4 mamp signal wire

I’ve used it for about 4 months now, has a light sensor so you don’t need a timer, 20lb co2 tank last about 1 month and a half compared to a week or two without the controller, easy to use easy to setup, keeps very steady co2 levels through the day, will buy again if needed

Had for a few months now. After my first tank, it started giving abnormally high ppm readings, in the 2000s, when I had it set at 1000. So I tried calibrating it for 5 days straight. I finally got it to pass calibration test after 100 fail attempts. So it worked great...great, for 3 days, then back to what it was doing before. So now I use it, just to dispense co2. I don't trust it, and I manually shut my tanks on and off from here on out. My Friedan brought his brand new auto-pilot master Gardner controller over, and we ran it along side this one to see how they coincide and they were 150+ ppms apart. I would not buy this again for the simple fact it does not work. Maybe I have a lemon model. At the end of the day I now need to re invest in another product and hope it doesn't end up like this product did.

Some people have complained about all the lights on the unit not shutting off during the dark time and causing their plants to 'hermie'. I don't have that problem with my controller. I have watched after 'lights out' and I have no lights whatsoever in the dark. The only time is when the controller is in 'Ventilation mode' and NOT in 'Greenhouse mode' did that occur on mine. 2 modes on this controller. In 'Greenhouse mode' everything shuts off on mine. However, a growing setup costs a lot of time and money, always check that all your stuff is performing as desired. For me , this unit has performed perfectly. Its not a $1000 unit, but it has been an excellent value for me.

Easy to use. Only wish mine was self calibrating for altitude. Turns out those are available but I was unlucky and got one of the last designs. Oh well, just increase the PPM target by 3% for every thousand feet in elevation. Had to call the company to ask some questions including the lack of self calibrating and they were very helpful and friendly like you'd want a company to be. One nights use and it's working as designed for a great price

A quality unit.