Slurry ppm way lower than runoff ppm...

[HeathBanks]

Ive heard that the slurry ppm's are supposed to be lower than actual runoff ppm, but my runoff result is 10 times higher than the slurry is!! I did a 2:1 r/o water to core sample, and let sit 15 min before taking readings. I even strained it with 75 micron filter and double checked readings.

Runoff was 1500ppm with pure r/o run through

Slurry was 150ppm


Is this normal to have such a wide range between the two readings? which one should i go by?

My plants are showing phosphorus deficiency and im trying to figure out if its from too much food, or not enough. Or if its ph.

 

[DONAJTHEIII]

Heath imo a slurry test isnt really ever a nec. you need to be worried about putting in the right water to your plants. A runoff of 1500ppm is a little high imo. You need to lower your nute strength and water until you get a good amount of runoff I think you should have your runoff no higher than 20% ppms/ec of your nute solution going in. My nutes mix is never higher than 1.2 and never goes below 1.0ec unless im doing a half strength nute flush every couple of weeks which isnt even nec. just like to be safe

So you need to keep your ec in a solid range like I mentioned above and then of course keep a good ph in coco Im assuming your in 5.6-6.2ph is what I do i like a little drift. Get a good meter if you dont have one already.


AJAE

 

[Andyo]

my run off

my run off

input a 2.0 ec ,last of run off is 1.6 using ro water .ph in 6.0 ph run off after 1 hr 6.2 ph after 2 hrs 6.2

try squeezing out enough after 1 and 2 hrs to get true ph in pot.A

 

[Snow Crash]

In both cases the snapshot of information is not very valuable. Watching your EC and pH from the start to see how it is changing with your feeds is where you can gain the information needed to make these kind of mid-grow reactions and troubleshooting.

Having said that, I'm kind of unsure how to read into the information. Instead, I think if you provide some history on the nutrients you are and have been using, at their levels throughout the grow, that we might be able to get an idea of if your ratios have been in the correct range. I will see some phosphorus deficiency after transplants as the plants produce a lot of new root tissue. Typically on the bottommost leafs.

If your plants have a deep, deep green color, like mixing green and purple together but still on the green-side of things... That could be a phosphorus deficiency. If you are allowing the media to get a little dry between feedings then it could be that the available phosphorus is precipitating with the abundance of cations in the coco which is locking out an otherwise healthy level. Feed regularly, with 60 to 100ppm of phosphorus (% on the label, multiplied by the ml used per gallon, multiplied by 1.16, will give you a rough estimate) and reduce the Nitrogen a touch and she should be good.

Pictures would be really useful... Everything I am saying is based on an assumption from your original post.