Soil runoff pH is high @ 7.8!!! I have an idea...

[ffgrowery]

Details about the grow:

• 4x4x6 tent
• 1000W HPS light, running %75, recently lowered to about 21" above plants.
• AC Unit set to go off at 75
• Temps have been between 68-78F (20-25C)
• Humidity between 35%-60%
• RO Water pH 6.0 with CalMag 1tbs/gallon. No neuts yet.
• Recently transplanted from 4" pots into 3 gal. Air pots.
• Soil is FFOF

I have recently re-potted my plants into 3 gallon air-pots, filled with FFOF soil. I have watered with pH 6.0 water, and let the runoff sit for a day. Once collected, the runoff tested pH 7.8! Before you ask, I'm using an electronic Oakton EcoTester, and I've recently calibrated it.
This worries me because I'm afraid that the actual soil pH is somewhere well above 8, and that it might cause nutrient lockout soon. The plants are looking pretty healthy, although some of the plants are significantly shorter than others, and are slightly more yellow.
Here's what I am thinking of doing. I am all for doing a flush in hopes of lowering the pH, but instead of wasting a ton of water, I'm thinking of collecting the runoff, lowering the runoff with pH down, and running it through again. Does anyone see a problem with this? I'm considering it might be good to recycle the runoff, and put all of the nutrients in the FFOF back in the soil, while lowering the pH.
Has anyone tried this? Would this work? I'm in Cali, and with the drought, I feel crappy simply wasting runoff water. I've also heard of people adding vinegar, or lemon juice to their water in hopes to raise the acidity. Any alternatives, or other solutions to this problem are welcome!

 

[evoleno]

If your plants are looking good don't do anything! Let them be, and give clean water if you really want to help.

 

[ffgrowery]

I actually ended up doing the slurry method of testing pH, and my pH came out 6.8, so I'm relaxing for now. The plants are doing great!

Slurry method: take soil samples from all of your plants, mix in pH 7 water, with 0 EC, basically anything under 30ppm (RO water, or distilled). Mix in until you get a nice slushy, slurry mix. Let sit for 10 minutes. Test pH.

 

[mack 10]

Some guys in Emerald County use water @8.4 pH !
but they are outdoor organic, it still amazed me they used so high of a pH
they also said the better aroma's and taste came from the higher pH.
crazy shizz.

 

[Granger2]

The soil pH and the pH of the water/nute you apply is what's important. I would NOT let your plants sit in the runoff, regardless of the pH. Vacuum it up right away with this: http://www.homedepot.com/p/Bucket-Head-Wet-Dry-Vaccum-BH0100/202017218

Best $22 I ever spent. Also get the extension tube and flat attachment. Good luck. -granger

 

[ffgrowery]

@Granger2

I owe you a beer! Brilliant Idea!

 

[Patmando22]

I do the same thing with the same vac works grate I don't reuse the runoff tho

 

[Granger2]

No, don't use the runoff. Also, the pH of the runoff needs to be measured immediately after it comes out of the containers for it be have any relevance. I've never checked my runoff pH. I don't think it is useful except in rare cases. Good luck. -granger

 

[SweetDee]

No, don't use the runoff. Also, the pH of the runoff needs to be measured immediately after it comes out of the containers for it be have any relevance. I've never checked my runoff pH. I don't think it is useful except in rare cases. Good luck. -granger

Well,in my case I had no choice but t use tap water from denver water co and I guess the hardness left deposits in the soil cause it was already 7.4 out of the tap and after a month wondering why the plants are not growing I check the run off and it was .7 higher then what I poured in . A distilled water flush brought the runoff with tap .3 over so I just accounted for that and everything took off.my first grow has had its ups and down but I'm learning ....also same ph tester as op.works great.