Perplexed to explain this!

New to dealing with Ph testing, having said that, it is taking more and more Ph down to get to my target reading as time goes by. At first use (after successfully calibrating) it only took a few drops of Ph down to get to 6.5, (tap water comes out at 7.7 Ph.) Now it takes 2/3 times the amount of Ph down to get to 6.5 (water Ph is very stable out of tap 7.7) I thinking maybe I need to shake the Ph down before use (like neuts) even though it does not say to shake in instructions. Or what explains this? I could understand this being the case if only after neuts added (more tds to deal with) but in plain water I don’t understand why this is happening! “SPLAIN IT LUCY!”

I give the bottle a quick vigorous shake or two before using. When I take the cap off and it’s bubbly, I call it good.

What brand ph down are you using. I use general hydroponics. My tap water is low 7s. I grow in coco and it takes about 6 ml to get to 5.8-6

I use GH as well, it just takes more to adjust than at start. Trying to figure out why. Having no trouble reaching my target Ph, just takes more GH down to get there now.

What do you mean by "than at start

I mean since I started watering and Ph-ING these plants as seedlings. The first water I Ph ed took about 4/5 drops of Ph down now 3x that much is needed.

Hey Audiofreak. Are your plants 2-3 times bigger? Are you feeding them nutes now vs. water only when they were seedlings? That is kinda what it sounds like and If so that may be it.

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Sorry, just saw your last line. Please dis-regard.

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Could be a lot of things. I thought questions above were worthy of asking. Nutrients will change ph, maybe amount of water you’re adjusting now is more?


When was your meter last calibrated?


Recalibration will be done today. The increase in PH up needed has happened with straight water (every other feed), and when using neuts. Still takes 3 times the “up” needed. Strange… can’t see any logic to this.

BTW I make up 1 gal at a time, neuts or just water.

While on this subject…water…I have been making 1 gal of water either w/ neuts or not. Ph ed to 6.5. Watering 3 plants with it, does this seem like enough water for one watering??? I get runoff at about 12 to 15 ounces and pretty much get a fair amount of runoff with gal. split between the 3 plants. Never sure I’m giving them enought water at each watering, I’m insucure about overwatering. Sooooo how much water should I use per watering???( I know it will very (temp,humidity, soil etc.) If it helps I am using FFOF with perlite added in 5 gal. landscape pots. They seem like they want water more often than my other grow and I think that is a good sign as they are drinking it up well and wanting water every other day or so. Response to neuts have been good no negative effects at 1/2 strength listed on package (FF TREO). Since no issues should I increase to over 1/2 strength??? (I’ve read many times here to not exceed 1/2 strength )

Could really use some input to the above question! Thanks.

It always takes mine at least a gallon per plant to get a solo cup worth of runoff that’s good for testing. I will get some runoff right away when the soil is dry because the water likes to bounce off the dry dirt and channel right out of the pot. I squeeze the sides of the pot to break up these channels and discard that runoff.

Depending on your solution ppm, you should be fine at 1/2 strength. I tend to stay around the low end of the Ppms that Fox farms has on their feed chart. Their ppms are on the .7 scale and my meter is .5 scale. So if they’re asking for 1750ppm, I’m looking for a 1250ppm reading on my meter

A few posts up you said it was taking a lot of ph up. That’s normal. Takes mine 10mL to bring it up from 6.1 to 6.5. I thought you were having an issue with ph down

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Typo. It was PH down not up! But situation seems to have abated. Checked calibration (AOK). Problem has gone away as fast as it came. The only thing I can try to explain Is that something in my tap water went Wonkey on that day and has returned to normal IE tap water is back to its consistent 7.7 Ph, neuts drop it to 7.4 than a few drops of Ph down and bingo 6.5. So… just guessing at this point but everything is back to “normal”. One plant was male (it’s gone) so I’ve got the 2 plants I planed on in the 4x2x5 tent and is pretty much filling the tent length wise and doing some LST. Concerned that I may run out of room.

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Glad you got it figured out!

Don’t know if I’d go that far. Can’t come up with any better idea/ LOL

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Crisis averted, anyway! :+1:

One for the books.