really good PH QUESTION!

[Suspectelite]

is it normal that when adding ph down a small ammount will cause a large fluctuation, & when adding ph up a large ammount will cause just a small fluctuation in ph?

[socialistpete]

Depends on what your using to lower and raise.

[PharmaCan]

Hmmmm - is that why my bottle of Up is so much bigger than my bottle of Down? :wtf:

There is no reason I know of why the Down is stronger, could just be the brand of product.

I mix my Up and Down with water and dilute them until they have about equal effects. (I pour some Up/Down in a bottle and dilute that.) This makes the chemicals easier to use - you don't have to dick around with such small quatities, and it also keeps my main supply of chemicals sealed and free from contamination.

PC :smokin:

[stinkyattic]

it also keeps my main supply of chemicals sealed and free from contamination.

Spoken like a true lab rat! That's the way to do things Pharma!

Just FYI in case anyone misinterprets, never mix pH up with pH down!

[Suspectelite]

Im using potassium hydrodroxide for up & phosphoric acid for down, does this make sense? pretty sure theyre both 80%.

[Help_Needed]

Im using potassium hydrodroxide for up & phosphoric acid for down, does this make sense? pretty sure theyre both 80%.

That's what I use, not sure on the concentration though.

One thing I've noticed with distilled water is that even though the native pH is 7.0, it is HYPER sensitive to pH Up & Down. Supposedly, 1/4 teaspoon of either will raise/lower a gallon of liquid by 0.5 - so 1/4 teaspoon of pH Down in 1/2 gallon of distilled water should give me a pH of 6.0, right? Nope lol. THREE DROPS of pH Down still drops my distilled water down to 3.2 :eek:.

So I've given up on trying to adjust the pH of my water before adding it to the reservoir. I just add distilled water as needed and then check the pH of the res after a couple of hours and *then* I adjust as needed.

[stinkyattic]

That makes sense. But where the heck did you get them?
Add these DROPWISE. I use KOH and HNO for my pH adjustments, lol... just be very careful, as concentrated strong acids and bases are dangerous, and should be treated as such:

-Wear gloves and eye protection while handling
-Store in shatterproof bottles
-Store in secondary containment adequate to hold the entire contents of the original bottle without overflowing
-NEVER store acids and bases in the same secondary containment
-Do not store oxidizers and acids together either (ex. hydrogen peroxide) or organic solvents and acids
-Check the containers regularly for leaks or cracks. Concentrated bases are pretty harsh on plastics, and even in poyethelyne (the best choice for storage, Nalgene brand bottles are made of this), you will lose bottle integrity over time.
-ALWAYS have very VERY clear labels on your chemicals!!!!! -Don't re-use containers
-Keep them away from small fingers.

[Help_Needed]

That makes sense. But where the heck did you get them?

Uhhh...the grow store? Standard bottle of pH Up and pH Down - potassium hydroxide and phosphoric acid :D

[Suspectelite]

That's what I use, not sure on the concentration though.

One thing I've noticed with distilled water is that even though the native pH is 7.0, it is HYPER sensitive to pH Up & Down. Supposedly, 1/4 teaspoon of either will raise/lower a gallon of liquid by 0.5 - so 1/4 teaspoon of pH Down in 1/2 gallon of distilled water should give me a pH of 6.0, right? Nope lol. THREE DROPS of pH Down still drops my distilled water down to 3.2 :eek:.

So I've given up on trying to adjust the pH of my water before adding it to the reservoir. I just add distilled water as needed and then check the pH of the res after a couple of hours and *then* I adjust as needed.
when I test my rez, I fill it, then I add my nutes, then I turn on my ph pen and ph correct while my pen is attatched to the side of the rez. I add 1 drop at a time until its at what I want it to be at.

& another question, does ph up & down add to the ppm of nutrient solution?

[stinkyattic]

Oh no shit. I didn't even realize that grow shop pH up/down was that simple! I work at a lab, and anything that isn't pure enough for our purposes just becomes waste. So I've never had to buy any, just raid the waste cupboards!!! :D