PK Booster Is Killing My Girls?

It is very possible that too much p and k was being the issue. Is this an auto?

What is you water source? Ppm and ph?

I have high ppm tap water and I it cut with RO to <100ppm. I was not a fan of running pure RO. My best results are using tap/RO or RO with some water soluble gypsum and Epsom 75ppm to buffer the RO. Plain RO by it self will go acidic pretty fast when exposed to air. You can also buffer the RO with calmag but you end up adding nitrogen too which was my issue.

By the way those plants look fantastic

I have no experience with your nutrients so hard for me to say there. I use megacrop and only use AN bud candy and Sensizym

Kilbarrog said:

The ph of my water is 7 after mixing their nutes.
I was actually wondering should I be mixing my tap water with the RO for the calcium, magnesium etc...
I'm was thinking about getting a "COM-80 EC Meter from HM Digital" (any good?), but I read you don't really need to measure PPM when growing with organic nutrients like Biobizz.
Although I know I'm using AN Bud Candy & Nirvana, so I water until run off of about a 1/4 of what I put in to wash away salt build up. They each get 2 litres of water in 6.5 litre pots.
First time using RO water, so kind of trying to read my plants & adjust accordingly

Appreciate the help & the nice comment too!!

Click to expand...

I’ve heard good thing about that meter but I use apera ph60 and ec60

Like I said I don’t know the nutrients you are using. But want to say they are salt based.

I don’t measure ppm in my organic setup but I only use dry amendments and water only RO/tap. I only use bud candy for the extra carbs it helps a lot with terps and flavor the last couple weeks 4 weeks max

Most everything I do is because of @Mañ'O'Green this is what he has taught me about using RO he's been doing this a lot longer then I have

"The history of why I invented stabilizing RO. When I first started using RO It did all manor of weird PH shit to my reservoir when I added it to bring the PPM down in a nutrient mix to the range I wanted. I used RO because it added only water to the mix. But it took copious amounts of up or down to keep PH in range. You know that PH+ Nitric Acid adds nitrogen, PH+ Phosphoric Acid adds Phosphorus to your nutrient mix. When you use large amounts it will change your nutrient balance. Keep in mind I am in hydro and my PPMs would change by as much as 75PPM. This was not desirable. Then I learned that RO water is hungry and will pull Co² out of the air and drop the PH to 5.5 or lower. I read somewhere that adding some base ions would mitigate this action. It can be any metal ion. I started adding a little cal-mag to the RO and Bota Boom Bota Bang it stop hijacking my reservoir PH. Then I discovered that everything mixed better without any precipitation I could see if I used this "buffered" RO. The reason I used 50 PPM of Cal_mag was because that was the lowest number my EC pen could read. Not all Cal_mags are made the same but most are calcium nitrate and Mg nitrate and maybe some iron once again a source of Nitrogen I don't want. Hence my choice of Soluble Gypsum which is Ca and Sulfur, Epsom Salt is Mg and Sulfur. Cannabis can tolerate a lot of Sulfur way more than you are likely to get in any nutrient line. I settled on .3g Soluble Gypsum and .3g Ag Epsom Salt per gallon of RO that gets me close to that 50PPM mark that most meters can read. It works well for me so I teach it."

I'd definitely be feeding P-K booster by now. Follow instructions; give less if still worried about P-K killing your plants; and there should be no toxicity.

I also know nothing about your base nutes. But it seems a little strange that well into bloom you are feeding 3 parts grow and just 2 parts bloom vs. feeding the same amounts (or even more of bloom, if recommended).

I see no downsides from mixing feed using pure RO water. I (and many or even most growers?) use it without adding tap water, with the base nutes and supplements along with the medium/soil and plant root system presumably having or adding enough salts to 'buffer' the pure water in the medium/soil. (This refers to up front addition of salts, not post-mixing pH adjustments).

I try not to add more salts when feeding, including giving any needed Ca and Mg (also Si) by foliar feeding; faster and no EC/ppm or pH effects on the medium/soil. [And using AN pH Perfect base nutes, I also never adjust pH, again avoid adding more salts].

But I'm a lazy grower; and doing top feeding with no reservoir. Also get other opinions.

I just noticed that Adv. Nutr. renamed some of their claimed truly "organic" hydro (fully soluble) nutes. For ex., see Big Mike's OG Tea Organic (at https://www.advancednutrients.com/products/og-organics-bigmikes-og-tea/), formerly Mother Earth Super Tea, bases nutes with grow and bloom versions. This is not pH Perfect.

If you want to top or bottom feed just like everyone else but do it with only 'organic' base nutes, this is likely a good option. And of course, AN and many others sell 'organic' supplements.