pH dropping in run-off water

[GotChaman]

Hey guys,

issue:

Top feed to drain, but before disposing of the used mix, we check the PPM and PH of the runoff water. Noticed that I feed at 6.1 to 6.3 and the run-off comes out at 5.5 ish.

Nutes used: 0-39-50, pureblend soil, cal mag, silicate, beneficial bacteria, full power, cannazyme.

Plants look good, are starting to bud, just curious what this means?
Doesn't look like there are any bugs, like aphids or mites.

 

[Snype]

Hey guys,

issue:

Top feed to drain, but before disposing of the used mix, we check the PPM and PH of the runoff water. Noticed that I feed at 6.1 to 6.3 and the run-off comes out at 5.5 ish.

Nutes used: 0-39-50, pureblend soil, cal mag, silicate, beneficial bacteria, full power, cannazyme.

Plants look good, are starting to bud, just curious what this means?
Doesn't look like there are any bugs, like aphids or mites.

What is your EC going in and your EC going out? If you are using PPM, please state which conversion your meter uses or brand of meter.

 

[GotChaman]

Using BlueLab combo meter. PPM going in 900, coming out 1200ish.. I dont use the electrical conductivity conversion. I guess I should?

 

[Snype]

Using BlueLab combo meter. PPM going in 900, coming out 1200ish.. I dont use the electrical conductivity conversion. I guess I should?

I believe that Blue Lab uses a 700 conversion scale for their PPM. If that's true then you are at watering at 1.3 EC and your run-off is 1.7 EC which is high for watering everyday. I would go down to 1 EC since you probably nute on a daily basis in coco. The coco is holding more EC than you are feeding and maybe when you lower the feed, you can get the medium to rise. You also could have a salt build up in there which is probably more likely.

Just people your plants look fine doesn't mean that they will stay that way. According to your run-off, your pH is not in line. Some plants can take pH swings like that for a little while but eventually it can catch up with the plant in time. Some plants are less sensitive than others.

 

[GotChaman]

I've dropped my PPM's to around 800-100... I give feed one day, and the next day just water... Basically flushing every other day. My PH is still around 5.2 - 5.4 max.

Someone suggested I let the nutrient sit for a few hours before I PH balance it... Tried that, same issue. Plants still look great, its week 4. Is this something I should be concerned about?

I've checked for root aphids, other bugs and nothing. All is good, except my run-off is ridiculously low right after I feed. Any other ideas?

 

[GotChaman]

I believe that Blue Lab uses a 700 conversion scale for their PPM. If that's true then you are at watering at 1.3 EC and your run-off is 1.7 EC which is high for watering everyday. I would go down to 1 EC since you probably nute on a daily basis in coco. The coco is holding more EC than you are feeding and maybe when you lower the feed, you can get the medium to rise. You also could have a salt build up in there which is probably more likely.

Just people your plants look fine doesn't mean that they will stay that way. According to your run-off, your pH is not in line. Some plants can take pH swings like that for a little while but eventually it can catch up with the plant in time. Some plants are less sensitive than others.

i actually use the 500 coversion. EC going in is around 1.2 somewhere there. Not too high.

 

[Trend]

Don't worry about it. If real worried collect extra run off like half gallon per 2 gallon of container then check it. Ec is high because I'm betting you are checking initial run off. Dump that. Check after.

 

[Green Fields]

Someone suggested I let the nutrient sit for a few hours before I PH balance it... Tried that, same issue. Plants still look great, its week 4. Is this something I should be concerned about?

Is it mixing thoroughly when you pH it? I.e get it at 5.8 and then leave for 15mins or an hour or a length of time more than 2 minutes...come back is it still 5.8?

Chances are you're just overfeeding by a bit. I mean that's what the EC runoff upticking tells you. When the EC is going up often pH is headed down. Least that was the case back in my hydro days. Coco my pH is always stable, runoff EC swings fursure

 

[Snype]

Some strains or pheno's are more sensitive to pH swings than others. I do believe that if you medium is that low that it's just a matter of time before you see problems with your plants if you don't get the pH back in line. Some plants take a while to show symptoms of low medium pH. This is my experience at least. My motorbreaths and stardogs were in a medium with a low pH. the motorbreaths showed symptoms really fast while it took weeks for the stardogs to show symptoms. The point is that I believe if you don't fix the run off pH, the symptoms will start sometime. We will see if I'm right or wrong. Keep us updated.

 

[Snow Crash]

The acidification of your media is due to a buildup of hydrogen cations (pH is a measure of the balance of H+ to OH- in your solution, more H+ means more acidic). Most times this is a result of over fertilization of Nitrogen, or the under abundance of other cations like Calcium, Magnesium, and Potassium.

Given the stage of growth you may want to decrease your ratio of N in the solution, as well as increase the amount of Potassium, Calcium, and Magnesium. Before making any reaction you should perform a slurry test.

The most reliable method for measuring the nutrient levels in coco is using the 1:1.5 extraction method. EC and pH of rhe root environement can be determeind by using this method. the pH and EC of the drain water generally deviates from the actual root situation, as coco is able to retain and release elements.
1) Take a sample of coco from the slabs or pots. This can be done with a soil core sampler or a trowel (spoons too). To get a representative sample the coco must be collected from as many places as possible.
2)Collect the sample in a bowl and determine whether it contains the right amount of moisture. The coco has the right amount of moisture if moisture disappears between your fingers when you squeeze it. Add some demineralized water if necessary and mix the coco.
3) Take a 250 ml measuring jug and fill it with 150 ml of demineralised water. Add coco to the 250ml mark. Fully mix and allow the slurry to settle for at least two hours.
4) Mix again and measure the pH
5) Then strain the water through a coffee filter and measure the EC.

A 1:1.5 analysis can best be done after 3 to 4 weeks. The target values for EC are between 1.1 and 1.3 for the pH between 5.3 and 6.2.
Very high EC values increase the risk of burning symptoms.

Let us know what your readings are from doing this test and we can help guide you a little better to a resolution (if anything is actually out of whak to start with).