Understanding the EC and TDS

GangaDownUnder

Well-Known Member
"Normal range" is subjective. Its plant and stage of growth dependant.

You didnt mention how big or what stage your plants are at but 773PPM seems high since I can see the base of one of the plants and it seems fairly small and untrained?

Im currently running about 550-600PPM in my resevoirs and I'll be flipping in about 2 days. I expect to get up to about 1000-1200PPM at peak flowering.

Test every day and the results will tell you if your in the correct range.
You want you PPM to stay steady or slightly drop/lower over a few days while your pH should slowly and slighly rise. That means your plant is drinking water and uptaking nutrients at about the same rate so the concentration (PPM) stays the same.
If PPM/EC goes up, then you've got too much nutrients on there and so its drinking eater faster than its uptaking the nutrients causing the concentration (PPM) to go up. If PPM/EC is dropping then you need to feed more.
 

Bucsfan80

Well-Known Member
Also it's hard to tell which measurement is temp and rh% but temp is low. You want canopy temps or leaf surface temps ( LST) 80ish°. So you gotta run temps higher than that, how much higher depends on your light and how much heat it puts out.
 

Cabrone

Well-Known Member
Here is a good chart for monitoring g your rez.UC Bible.jpeg
Also a great thread with info about ppm and ec.
 

GangaDownUnder

Well-Known Member
If those young plants take that high ec I'd be surprised.
Agreed.

Nightrider798, did you calibrate your EC meter prior to use? Maybe its out of whack?

And it'll be obvious when you get it all dialled in as you'll see relatively explosive growth. After growing in canna terra pro and then coco for like 8 years I was shocked at the speed of growth in my DWC setup.
 
Thank you for the advice. I've got my Ec down to .8 and my ppm is 402, water temp is 75 and the room temp is 77 room humidity is 66. The plants seem to doing better then I get up this morning and a couple leaves are drooping any advice. I thought it could be wind burn so I moved the fans back and repositioned them.
 

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Star Dog

Well-Known Member
The ec is more relevant to the environment than anything else, in hot dry environment water gets transpired quickly raising the ec.

In cooler humid environments the plant doesn't transpire as much so you need a higher ec to compensate.
 

Rubisco456

Member
Before you take your first EC readings did you take the EC of the nutrient solution and the same temp as the grow tent (or what ever environment you are in)? The EC/TDS readings will drastically change with temperature and you you may be basing your feeding decisions off of incorrect measurements.
 
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