Grow Mediums What should I do to stop water stagnating?

[SweetSkunk]

Glad you asked. That's why I said fill the tank up to 120L in stead of 150 and why I would adjust the pH to 6.5.
If you're in Hydro or Coco You can still go down and if you're growing in soil just add water to go up

I'll give my setup as an example.

This season I'm growing in buffered Coco with 30% Perlite added to it. So my range for pH would be 5.5 - 6.2.
My nutrient tank is 60L Which in hindsight is on the low side, but that's an issue for next season.
While I'm filling the tank with tap water (pH 7.8 EC 0.18) I add between 12 and 16ml of acid. 12ml if I want the end result to be pH 6.0 and 16ml if I want it to be 5.5.
Then I add 6ml Potsil or in my case Potassium Silicate (which is wayway cheaper). This will counteract the amount of acid as Potassium Silicate has a very high pH. Then I add my A+B nutrients.
By the time I have everything added my tank is almost full and it's time to measure. I stop adding water so I have room to spare in case the pH is to low so I can add more water and have a syringe ready with a couple of ml Sulfuric acid in it to lower it if needed.
Then top of the tank so it's completely full and let the airstone do it's thing.
The next day in the morning I measure the pH and EC again and adjust.
You'll get the hang of it. Just make notes of everything you've added and compare after you're done. I can't stress that last one enough

Oh, one note (and it's an important one)... Adding acid isn't something that's linear. What I mean by that is that if you need (for example) 10ml of acid for 50L of water to change from pH 8 to 6 and you add 10L of water to the already pH lowered tank you would need 2ml more to come to the same result. That's not the case. There's all sorts of of chemical reactions taking place one being the Calcium carbonate which is added by the water company to buffer your water and those need to be accounted for. So in the beginning take it easy with adding acid to your tank or you'll need to throw half of it away just so you can add more water to raise the pH again. Just note how much you've added and calculate when you're done. After a couple of days making notes use the average and test it out. You'll be amazed how fast you can accurately mix your 150L tank

Regards,

Bob

this is a project for next weekend! thanks for your help bob. I will update!!

 

[Hypathetical Gardener]

If you're not using the water storage vessel for anything else I would recomend you premix everything in there and add an airstone. It's much easier to regulate a large quantity then a smaller (10L bucket) one.
Also because of the hard water you have you'll most likely notice that the water in the large container doesn't keep it's pH steady for the first couple of days. This also happens in your medium with the disadvantage that it's not easily corrected.
What I would do is... Fill the vessel with 120L of water and add about 10ml of Sulfuric acid. Put your airstone into that and let it bubble away for a couple of hours. Then measure the contents. If the pH is lower then 6.5 add more water until the pH is 6.5 ish and note that you use less Sulfuric acid the next time.
Now the next day you measure the tank again and you'll probably will notice that the pH has risen. This is normal as the Calcium in the water reacts with the acid. It's doing it's job buffering the pH. When the pH is stable you can procede with adding nutrients in the tank or continue by adding them in the bucket. I recomend adding them in the large vessel.
The most important thing is to take notes...
How much water added. Amount of acid added and so on. Once you've got this dialed in you'll know how much acid you'll need to pH down your water so the outcome in 24h is always the pH you want

Regards,

Bob

Wait.... Ive been letting my hard tap water (on the liquid ph test, it turns blue) sit for 2ish days with no ph adjuster. Then i add my nutes (lowers ph) then i ph it down from there...
Should i be ph ing the water down to 6 (where i keep it) before adding nutes? Wouldnt that drop it further? Or am i missing out by not adding the acid to the water first?

 

[Death The Cultivator]

There is a product by a company called Torushydro that supposedly maintains pH for two-four months. It's up there in price but it would keep your water moving and lower the need to pH in general.

Product Results | Torus Hydro

For your system and media, using mineral nutrients, 35gal (or less), we recommend using the PerfectpH Inline Edition 35gal. Larger models can also be use for less frequent recharging. See all models applicable for your system listed below: RECOMMENDED: OR UPGRADE, FOR LESS FREQUENT RECHARGING...

www.torushydro.com

 

[Bob's Auto's]

Wait.... Ive been letting my hard tap water (on the liquid ph test, it turns blue) sit for 2ish days with no ph adjuster. Then i add my nutes (lowers ph) then i ph it down from there...
Should i be ph ing the water down to 6 (where i keep it) before adding nutes? Wouldnt that drop it further? Or am i missing out by not adding the acid to the water first?

Hey HG,

When you add an acid (or base) to your nutrient solution it will instantaneously react with the chelated nutrients in your mix. This will break the chelate bond and make those molecules inactive. That being said, it is a local phenomenon which will stop as soon as the extreme pH dissipates in the liquid, but extreme high or low pH is not a good thing for some of the ingredients in your nutrient.
That's why I explained the way I fill my nutrient tank. While I'm filling the tank I'll add everything starting with the acids and bases (Potassium Silicate) so the churning water will keep everything moving and mixing. And no extreme pH situation is created.
You'll have to experiment and make notes while mixing so you know how much of everything you need to add as to prevent having to add an acid or base after you've added the nutrients in the tank.
Again, this is best practice. In reality you'll always have to make minor adjustments to the pH, but the impact of just a couple of drops Sulfuric acid to the tank is negligible in comparison to adding let's say 14ml of acid.
You can test this by pouring some of your nutrients in a cup. Add some water to dilute and then add a ml of acid to that. You'll notice that the color will fade. That was probably the iron in the mix that got separated and is now unusable for the plants.

Oh, and just one more thing... From your comment I understand that you are using pH sticks (something like the picture below)? These are really not accurate enough for what we are doing. At the bear minimum you should be able to measure accurately to one decimal. As 0.1 difference in pH is 10x more acidic or basic. To measure that you'll probably have to switch to a pH pen of some sorts. I use a reasonably priced one (approx. 25$) from Ali which can measure to two decimals which gives the certainty that the first decimal is always correct.

Regards,

Bob

 

[Hypathetical Gardener]

Hey HG,

When you add an acid (or base) to your nutrient solution it will instantaneously react with the chelated nutrients in your mix. This will break the chelate bond and make those molecules inactive. That being said, it is a local phenomenon which will stop as soon as the extreme pH dissipates in the liquid, but extreme high or low pH is not a good thing for some of the ingredients in your nutrient.
That's why I explained the way I fill my nutrient tank. While I'm filling the tank I'll add everything starting with the acids and bases (Potassium Silicate) so the churning water will keep everything moving and mixing. And no extreme pH situation is created.
You'll have to experiment and make notes while mixing so you know how much of everything you need to add as to prevent having to add an acid or base after you've added the nutrients in the tank.
Again, this is best practice. In reality you'll always have to make minor adjustments to the pH, but the impact of just a couple of drops Sulfuric acid to the tank is negligible in comparison to adding let's say 14ml of acid.
You can test this by pouring some of your nutrients in a cup. Add some water to dilute and then add a ml of acid to that. You'll notice that the color will fade. That was probably the iron in the mix that got separated and is now unusable for the plants.

Oh, and just one more thing... From your comment I understand that you are using pH sticks (something like the picture below)? These are really not accurate enough for what we are doing. At the bear minimum you should be able to measure accurately to one decimal. As 0.1 difference in pH is 10x more acidic or basic. To measure that you'll probably have to switch to a pH pen of some sorts. I use a reasonably priced one (approx. 25$) from Ali which can measure to two decimals which gives the certainty that the first decimal is always correct.

Regards,

Bob

Thanks for that. Ill adjust my mixing teq in a few weeks when i start using nutes again.
I will use a ph pen eventually. Im using the liquid drops ph test that changes the liquid a color. Pic included. It gives a color gradient in .5 but ive peen aiming for piss yellow (6) all thru. I ran a lil green in veg and a lil to the orange tint in flower. I definately saw an increass in yield just by adjusting ph. I didnt check my ph for years. This is my first time. im already at my 1g/watt goal with 3/4 plants down and in jars.