DIY PAR meter, Yeah you heard me
Ok, send me back the meter and I'll refund you. Something is wrong electronically. The photodiode might be blown. It happens. I'm getting normal readings here against t5-ho bulbs. I'll pm you.
Ps. I just checked reading on my DIY led. Readings are dead on. Let me give everybody a tip, on any light sensor, when you're measuring up close to a light source like a bulb, they are wildly variable. You can have one measurement and move the sensor closer to the light by an inch! You can get double the reading. The angle of the sensor can vary the reading as well. Published readings from light manufacturers can be off as well. Take the tip for what it's worth.
For aquarists, the only reading that really matters is the reading on the substrate. That'll give you an idea how much you have and it's physically fixed. You don't need to eyeball the distance to the light.
Sent from my iPad using Tapatalk HD