I don’t understand this stuff so much. So I’m trying to test my run off. Getting worried because the tds meter is reading 3600 to 3800 ec and I’m pretty sure that’s high because it’s not on the conversion chart. But I’m also using soil witch adds to the number i guess. I’ve read up on it but i can only learn so much from reading. I’m a hands on kind a guy. I have tested the tap water i been aerating for a day and it reads 660 to 700 ec. 300 to 350 ppm. The run off i tested is from my gorilla glue auto in a supersoil mix 3 gallon fab pot. Going on second week of flowering.
How long do i measure the run off for. When i first put it in it slowed down around 2600 ec but slowly kept climbing as i left it in there. After like a min it kept bouncing back from 3600 to 3800. Did i leave it in to long? It’s new should i have to calibrate it before use.? Any help will be appreciated. Thanks
Must be an error or reading it incorrectly. Those numbers would be more of your PPMS and an EC value would be 2 times that. The most common is the 500 scale. I mix my nutes at 900-1000 PPMs and 1.8-2.0 EC. To accurately measure run of you would collect a sample of the water/nutrients coming from the bottom of the pot after a few seconds of run off. What type of medium are you using? Coco or soil? This will determine your feeding frequency. Coco can be watered/fed daily with soil needing a wet/dry cycle. Both need to watered/fed to approximately 20% run off. This will prevent salts and minerals from building up in the root zone creating lock out of nutrient uptake and give you the high run off numbers. The run off numbers shouldn’t vary from what you’re putting in by 200, above that typically means a root issue commonly fixed by a flush and reset 
Soil is a subcool mix with ffhf using the 1/3 layer. The medium i used for the other layers are half Coco and half plain ffhf with a splash of perlite. I should mention that just over a week ago i gave it it’s first tea for flowering.
I took the first bit of run off that came out. Should i have watrered it a bit more and tried testing that?
How are PHing the water or nutrients for this mixture. 2 different mediums that require different PH
Water ph is around 6.3. I measure ph in the soil before and after. Average before is around 6.8 and i wait about 30 min after watering then check and it settles to 6.6. I’ve only fed it the 1 tea so far. Same ph range in the tea. But i never tested it with the tds meter. I just started using it. Trying to figure out how to use this properly and understand the ppm.
Mixing coco and soil might be a PH issue