A couple of PH questions

[Agen36]

I recently purchased my first digital PH meter after a year of growing. Purchased at the outset it might have saved me a lot of heartache.

Right off I noticed I've been using 7.5 tap water. Luckily two teaspoons of lemon juice brings a gallon down to 6.5-lovin' that!

I did notice that untreated tap water left out to de-chlorinate will work its way up to the middle 8's from 7.5. How come? Or am I dreaming?

Secondly, why is it necessary to test the runoff after watering and how do I interpret the results?

Thirdly, will grow or bloom nutrients alter waters PH substantially and if so how do I adjust?

 

[danklover79]

I catch my runoff in a small coffee cup, then test it, if the runoff ph is high, I set the solution ph lower to offset. Like if the runoff is 7, I'll set the solution ph at 6, and it will usually settle at around 6.5, unless there's salt buildup, then the ph will be jacked up til you flush. I have noticed the ph will rise in 24 hours as well, though I don't know why just seems to happen when you leave it out.

 

[Agen36]

I have noticed the PH will rise in 24 hours as well

Wonderful... when I think of all the times I must have poured high PH water for my plants over the last year, well it makes me sick. I guess I only have myself to blame.

Thanks for the tip on the runoff!

 

[c526]

are you guys just leaving the water sit?? I have my tap water in a 40 gal trash can,with air stones and a recycle pump.After a couple of days, my tap water goes from mid 7 to an even 6.My ppm also drops from 360 to an even 300

 

[Pop The Trunk]

I recently purchased my first digital PH meter after a year of growing. Purchased at the outset it might have saved me a lot of heartache.

Right off I noticed I've been using 7.5 tap water. Luckily two teaspoons of lemon juice brings a gallon down to 6.5-lovin' that!

I did notice that untreated tap water left out to de-chlorinate will work its way up to the middle 8's from 7.5. How come? Or am I dreaming?

Secondly, why is it necessary to test the runoff after watering and how do I interpret the results?

Thirdly, will grow or bloom nutrients alter waters PH substantially and if so how do I adjust?

Minerals and contaminates (ie Chlorine. Fluoride) raise and lower you PH, just like when you add nutes to a bucket of water the PH of your water will go up or down (i use GH and it always lowers my PH). As these Minerals and Contaminates evaporate (leaving water out overnight) and are no longer in the water, your PH will naturally change because those minerals and contaminates are no longer having an effect on your water. I use a 40g hempy tub, i usely use 3-4 gallons of water/feed and how i know its time to change or drain the tub before all the water is used up is ill check the runoff from my drain valve and if the PH is really high and out of the nute absorption range i know the plants have used up all the nutes, sometimes they use all the water with the nutes sometimes they use just the nutes it all depends on the stage of life of the plants. So thats why your PH changes when you leave water out over night, anything added or taken out of the water is going to effect the PH.

 

[danklover79]

When your ph rises and your ppm drops the plant is using more nutrients than water. When the ph drops, and ppm rises, the plant is using more water than nutrients. The reason it is good to check the runoff, as I think you guys already know, is so the plant you can the plant to the limit with nutes, increasing production. Ph is probably the most important factor when it comes to nute absorption, either in hydro or soil.

QUOTE=Pop The Trunk;1891917]Minerals and contaminates (ie Chlorine. Fluoride) raise and lower you PH, just like when you add nutes to a bucket of water the PH of your water will go up or down (i use GH and it always lowers my PH). As these Minerals and Contaminates evaporate (leaving water out overnight) and are no longer in the water, your PH will naturally change because those minerals and contaminates are no longer having an effect on your water. I use a 40g hempy tub, i usely use 3-4 gallons of water/feed and how i know its time to change or drain the tub before all the water is used up is ill check the runoff from my drain valve and if the PH is really high and out of the nute absorption range i know the plants have used up all the nutes, sometimes they use all the water with the nutes sometimes they use just the nutes it all depends on the stage of life of the plants. So thats why your PH changes when you leave water out over night, anything added or taken out of the water is going to effect the PH.[/QUOTE]

 

[Agen36]

Thanks Pop The Trunk and Danklover, I appreciate your explanations; they help a lot!