Nutrient reservoir pH swing

[Highflyer580]

Needing a little info..
Jus started up my grow gonna have a drain to waste system with 20 25 g res..
I am in coco using canna coco products
I have really high ppm tap water..450-+ a few and a 7.2ph ive decided to use rain water to dilute my tap water and bring it to roughly 225 ppm then adding canna coco a + b and camg which bring my ppm to a little above 500 and adjust the ph to 5.8 to 6.1 ish

So i made a small batch 2g 50\50 tap\rain adding roughly half strength nute and what not phd to 6.1 check ph next day it had risen to 7.5ish so i went ahead and lowered again bringing it to about 5..9 well once again the ph it back up above 7!!!
My seedlings jus broke ground and dont wanna biff up my first grow could the ph change due to the small batch? Help a fellow stner out lol

 

[TurboBucket]

With the small batch are you checking pH after thoroughly mixing it? Or after it has settled? I know with bigger batches they say to let it circulate for 30 mins and recheck. I run mine empty every day or two days depending on how many tents are running. So I just fill it with new solution. If it drifts to 7 by the end of the day oh well it's getting new 5.5 stuff in the morning.
You want some drift with your solution or you'll lock out certain ranges of nutrient uptake.

 

[Highflyer580]

I do have a air atone in the small batch bucket so i dont really think it gets to settle to much and i even gave it a good stir and re tested it with a .05 to .1 change in ph...so what i dis this morning is...pilled about a cup of the nute solution into a jar and diluted with collected rainwater and phd it down to 5.5 to water my freahly sprouted seedlings and im jus hand qatering as of now so its not to big of a deal to pH it it before use but once the babies are big enough ill be going to w automatic drip system {being i have a busy shedule} watering to waste multiple times a day and dont think its beneficial for my res ph to br going up like that

 

[TurboBucket]

I run DTW. Multiple irrigation cycles per day as well Fwiw.

Try monitoring a batch with only rain water, it's possible your water quality is causing some stuff to bind up.

Again you want some drift but not that much that rapidly. Some nutrient lines hold pH better than others. I use Dyna-Gro and am happy with it. But I also don't need a rez to stay stable longer than 3 days.

 

[Highflyer580]

I jus read another forum fron and alot of ppl and saying the airstones running constantly will have lot to do with pH going up and once they cut down airstone time to jus 15 min 3 times a day they stop having pH issues which could be the case since i was bubbling 2 gals of nute solution with a 10 gal ait pump so imma try that first and see what it does if anyone has had similar prob but diff solution chime in plz lol

 

[TurboBucket]

Yes air stones will contribute to pH swings. I don't use any.