Mixing nutes and pH adjusters in Hydro.

O.K. Peeps. So here's the story. I've grown in a few different environments/places in hydro and have never really thought about how I make my res fluids up. It just tends to go with whichever way is convenient at the time.
As an example, I currently have a 250w mini-grow going with a 40L res. I tend to fill res with 10L buckets in the following order.

Bucket 1. Water and part A of nutes (2-part canna Aqua)
Bucket 2 Water and part B
Bucket 3 pH down as required by experience (heck, I even throw it in by eye now and get pretty close)
Bucket 4, plain water.

I check the pH on day two, correct and it tends to stay stable for a week/2 weeks depending upon growth stage.

I am no expert in hydro (soil is my speciality, long story but basically a degree in soil science through my career, but I prefer hydro indoors, only got half a dozen hydro grows under my belt). It has left me with a lot of holes in my knowledge and a lot of unanswered questions (compost teas and mollasses etc effect in hydro) It really is a whole new world.

So, my question is, in what order do you add 2-part nutes and pH down (Phosphoric acid) when changing the res? I am thinking that the solubility of some nutes are variable at different pH levels so it's better to allow the pH to fluctuate during the mix hence it could be better to mix the nutes before adjusting pH to allow them to dissolve. Or will they just fall out of the solution once the pH is adjusted?

Opinions please?

I've never had any issues mixing A or B in different orders. It could depend on which line you use, though. Just avoid mixing anything concentrated. I'd suggest filling your reservoir all the way up with water, THEN adding the A & B.
pH is last. If you adjust pH before adding nutes, you'll have to go back and add pH up.

PH after mixing your nutes.

Yeah but I already know how much pH down I need. I can't help thinking that if I start with water (ph 7.8 and part A&B, then bucket 2 PH down followed by 2 plain water, it will go through the alkaline-acid range and help the nutes dissolve.

I used to ph my water to exactly where I would need it then add nutes.... always a then b or Mirco/camg first depending on the line i was using...If you

Once you know where your filtered water is at it seems pretty easy to know you need x amount of ph up or down .

Now the one thing I know that I see alot of people do wrong is adding ph adjuster straight to the res. without diluting them in water or something first.

This can cause all sorta percipatation issues and such.

How would one correctly add ph down in a setup like this?

Take out 5-10L of solution, add PH down to that, and then add it back in?

If the roots are in the solution, I imagine it's a bad idea to add ph down directly to the water?

Take a bucket or cup of water depending on how much ph down your adding... add the ph up or down to that water first so its nice and dilutated.... mix it up let it sit for a few then mix that diluted water/ph adjuster solution into your res. ( btw do not take the water from your res. use fresh water to dilute the ph adjuster in )

Maybe I'm not making myself clear enough here. Sorry,
What I am talking about is making the A&B solution up, then taking it through a pH range to ensure all elements are dissolved before bringing it to a stable pH of about 5.6-5.8 instead of keeping pH more stable throughout the mixing.
I guess I am saying that by taking the nutrient through the maximum pH range during mixing (and while in the res, not pumped through the substrate), surely we can dissolve more nutes more effectively?

why dont you just ph to 5.5 then let it go back to 6.1 then go back?

Because I want to go through the acid-alkaline range to ensure maximum solubility of nutes across the range. Is it me being thick or something?

explain what you mean by "taking through a range" you ph it all the way up then ph it all the way down before getting to 5.6?

well......

Yeah, within the limit of what we are using anyway. I don't mean chuck loads of pH up in then loads of pH down.

Your adding extra chemicals to your roots for no reason at all. Imagine if you were lounging in the pool and the pool guy added a shit load of chlorine to "take it through the range". Your eyes would be fuked, so why would u do that to your roots?

No, I'm not. I'm adding exactly the same amount (about 28ml phosphoric acid in 40 litres water+nutes).
All I'm doing is changing the order of mixing it all to take the nutes through a wider pH range while mixing.
Am I not explaining myself clearly here or something?

Do you have a tds pen? Sounds like your doing a lot more work than you have too. I would mix all in one pail, check the tds to make sure your range for their age and then ph down to 5.5-5.6

Starting your girls at 5-5 and letting nature run the ph up to 6ish will run your gils through the whole scale. Then either change it out completely of top it up with fresh nute water balanced.

A ph of 5.8 overlaps all mineral/nutrients and should be what your run off is if your doing things correctly.

Good Luck

Cues I sorta kinda see what your saying, but it wont make any difference all water soluable nutes will already be dissolved and have no need to "run the range" if anything this mixing and varying of the range might actually cause percipate and micro nutes to lock each other out if mixed in an inproper order.... like adding a cal-mag or micro product last.

cues said:

Maybe I'm not making myself clear enough here. Sorry,
What I am talking about is making the A&B solution up, then taking it through a pH range to ensure all elements are dissolved before bringing it to a stable pH of about 5.6-5.8 instead of keeping pH more stable throughout the mixing.
I guess I am saying that by taking the nutrient through the maximum pH range during mixing (and while in the res, not pumped through the substrate), surely we can dissolve more nutes more effectively?

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The more ph up or down you use adds to the instability of your res. You really want to add as little as possible. Mix your additives in then your mycos and bennies and then finish with your base nutes. let your res sit for several hours 4-6 the mycos and bennies that you added will gradually raise your ph over time. heck leave it for a day if your set up permits. the point is add every thing then let it sit. you don't need to "let everything dissolve" take a stick or something and stir your res up if thats needed but seriously unless you're using organic nutes you shouldn't have to "wait" for your nutes to dissolve. after the ph has stabilized then add your ph adjuster. I use an auto dosing ph meter with pump from hanna so when I mix my res and it comes out at 5.2 to 5.5 I just leave it beacuse my mycos and bennies will raise that ph. then when it gets too high (5.86) my meter brings it back down to 5.8. My point is I use as little as possible of ph adjuster.
whew...sorry I just woke up and medicated....straight oil as a wake and bake is always nice

Sir.Ganga said:

Do you have a tds pen? Sounds like your doing a lot more work than you have too. I would mix all in one pail, check the tds to make sure your range for their age and then ph down to 5.5-5.6

Starting your girls at 5-5 and letting nature run the ph up to 6ish will run your gils through the whole scale. Then either change it out completely of top it up with fresh nute water balanced.

A ph of 5.8 overlaps all mineral/nutrients and should be what your run off is if your doing things correctly.

Good Luck

Click to expand...

My run off is usually 6.0....U think thats a bit high for hydroton?

devolv said:

My run off is usually 6.0....U think thats a bit high for hydroton?

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No not really you are only loosing, .2-.3 of whatever nutes/salts yours plants are uptaking and your bennes are using.... so that seems pretty normal and well within range seeing as range can be 5.5-6.5 and i have seen people that run areos and dwc as low as 5.3

Personally if my mix falls within 5.8-6.3 I don't even ph adjust it as I find it does more damage then good, especially with higher ppm flowers solutions as it takes a shit ton of ph adjusters to move the range even like .2-.3 points... and for a soilless base like coco 5.8-6.3 seems to be the sweet spot.... shoot with my premix "soil" type mixes I'll a range of 5.7-6.5 just because the medium buffers ph so well.