Monitoring sensors under full spectrum led have different readings, only during light on

ha.. 'don't hinder air flow...' not flower... flower is on the mind.

These devices are +/-5% so that's within expectations. Definitely don't hinder air flower near the sensor, that'll make for a greater deviation. Inside is a hair-like folicle that contracts and expands in a consistent way relative to moisture... this is typically what is used for the cheap hygrometers. It does not directly measure RH just as a TDS pen does not directly measure PPM. It's using a correlation, that is much stronger than the EC-ppm conversion factors out there as seen by the +/- 5% error. maybe, one probe is more accurate in a given range that differes from the other - some sort of mechanical difference in how it's made or quality control differences etc. These are not high-precision instruments, but they do a good enough job for this context. Do you have any boveda 2-way humidipacks? put the sensors in a sealed container until the rh reading stabilizes.. those would give a good idea of the error in the reading. boveda seem to be +/- 1% maybe 2%. Integra boost suck ass, don't use those as they are nowhere near advertised RH%. If you have 'something' that creates a known and consistent RH, put the probes in a sealed container with it and take note of any offsets. IF you think range of temps are impacting accuracy, test at different temps and see if those offsets change. if additional deviations exist, probably related to manufacturing differences / quality control of each company. RH% is used because that is what matters as far as how easily water is drawn out of or gassed off into the atmosphere. This is what impacts the "why" of VPD, this is what allows microbes to more easily draw water from the atmosphere - or not. Absolute humidity is important to keep an eye on to avoid hitting the dewpoint when your lights go off and temperatures drop. Even though they are based off the same thing (moisture), they are different units of measure that are both important and used in appropriate ways at any time it is relevant. Absolute humidity is not relavant to this question. not sure why it was mentioned.. just a convoluted explanation for no reason.

There are three primary types of humidity sensors: capacitive, resistive, and thermal conductivity humidity sensors. Capacitive and resistive humidity sensors are designed to sense relative humidity (RH), and thermal conductivity sensors are used to detect absolute humidity (AH). While both absolute humidity and relative humidity provide insights into the moisture content of the air, they differ in their approach and interpretation. Absolute humidity focuses on the actual amount of water vapor present, providing a direct measurement of moisture content. In contrast, relative humidity considers the relationship between the actual moisture content and the air's capacity to hold moisture at a specific temperature. One key distinction between the two is their units of measurement. Absolute humidity is typically expressed in grams per cubic meter or grains per cubic foot, representing the mass of water vapor present in a given volume of air. On the other hand, relative humidity is expressed as a percentage, indicating the amount of moisture in the air relative to its saturation point at a specific temperature. Another difference lies in their calculation methods. Absolute humidity requires the measurement of the actual mass of water vapor, which can be obtained through various instruments or complex equations. Relative humidity, on the other hand, involves comparing the actual moisture content with the air's saturation point, resulting in a percentage value. Both absolute humidity and relative humidity have their practical applications. Absolute humidity is particularly useful in scientific research, industrial processes, and agricultural practices, where precise moisture measurements are required. Relative humidity, on the other hand, is widely used in weather forecasting, indoor comfort assessments, and determining the likelihood of precipitation. It is important to note that absolute humidity and relative humidity are interrelated. As the air's temperature increases, its capacity to hold moisture also increases. Therefore, if the absolute humidity remains constant while the temperature rises, the relative humidity will decrease. Conversely, if the absolute humidity remains constant while the temperature drops, the relative humidity will increase.

one might be off or both. Can always test it out and place the sensors into a jar with a some fresh/new humidity packs and see how close it gets to the advertized RH of the packs. can always tape the hole shut in the jar if the RH probe is on a long cable to the control unit. I use a RH probe that connects into my tent fan controller, I also used to have a mini shelf one. they where always with 5% of each other. but then the other one would not go above 30% it just broke so I had to get a new one. they do not last forever and I find have a 1-2yr shelf life. If anything I think the inkbird would be a more accurate device and should be considered the go to. but test it out.

It's probably a combination of the margin of error between the products and differences in the location of your probes. Microenvironments exist throughout your canopy, mostly due to differences in airflow, that will affect your numbers.

Well I've no experience of Spider farms stuff but I have an inkbird humidity controller and a g.a.s. fan controller with humidity control too and like you the two never agree. I also have an inkbird temp/humidity/vpd monitor and it doesn't agree either. So I think an expensive calibration device is required and some places rent them but not where I am and they're 800euros to buy. Fluke is the company that makes them.

Hello there sometimes the humidity can be at different levels throughout the tent especially durring winter with heaters on in people houses. It's possible the 2 devices have variances and just are reading wrong. Your best bet is try and control the humidity level in the room the grow tent is in. We will call this the lung room. Make sure to get the lung room at the right temp and humidity and should help keep the tent at a stable temp and humidity.