TrichCrazy said:

I completely agree. In my opinion and from logical thinking testing the run off for PH is good but for salts its a false reading. I have had whole rooms of plants that the runoff was maxing out my pen when i collected the first bit of runoff. But when i did multiple slurry tests my pen was not even registering. The plants were hungry for food, i fed heavily and they all bounced right back in a couple days.

Doing runoff tests to try and determine my mediums salt levels has really slowed me down in the past. I would see those high run offs, flush heavily and watch the plants just get even worse and worse.

And to the original post question. Are you using a high grade coco mix?? As i am sure you already know if its a low grade non rinsed product it could be binding up your calcium??

Click to expand...

Sunshine Ultra Coir. Thats decent grade?

Hey @neewb432 I have been running in CoCo hempys and 3 gal air w/coco I cut two flaps and can access the coco from a few places in the bag. when I measure the run off straight from the flush its high and that's wrong, IMO...

A much more accurate way to get the reading is to.......
a sample of the coco from 3 spots mixed in a cup with the Reg water that I use to feed with it mixed up with the coco in three separate cups I feel 3 places is a good way to check 2/3rd down the pot 2 inches in ok then after about 5-7 min I set my PPM meter and PH take a reading .>>>
for me this works and is by far the only way to get a good reading IMHO
good luck with your grow
BTW add 1 teaspoon of Epsom salt to 5.5 water check it then add to your plants that are showing deficiency signs ONLY if your slurry test shows active transport of elements, ie food nutes H^ (PH up and ppm down) indicate active transport
Peace
And what ever Seamaiden says is Magic I would trust what she says as gospel.
FlyJ