PPM pen stopped working

Hello hope you’re all doing well. I just went to go feed my ladies and my PPM pen doesn’t work. Does anybody have any suggestions on one that is cheap but reliable? I do appreciate your feedback

Do you add more nutes when you ppm aren’t “where you want them”… if so how do you know to add how much of what your regiment should be fairly thr same and additions of amendments should be done gradually introduce low levels and increase the bottles usually have a guide and if you follow the guide based on what you been doing and ppms really don’t matter if your doing the same thing or adding it subtracting gradually until u get a pen if that makes u more uncomfortable but I’ve been growing for almost 3yrs and never made an adjustment due to ppms I follow my guide and plus or minus accordingly …do some research on your nutes and see exactly what each does for when and why and it becomes intuition over time :v::sunglasses:
If you insist on knowing …and or its its ph all in one then I’d replace it soon cut ph Is more important then ppms if you’ve watered more then 3 times you know what I mean …meaning you gotna general idea what your doing for the time being

Are u using same manufacturer on your food or are you picking and choosing and piecing together your own concoction… either way know what your doing and why is best advice I can give you … how many bottles of what are you using

I use Fox Farm Trio for now. I ppm I feed and then I PPM the runoff.

Do you make adjustment based on your outcome of your tds reading before during and after? Or do you just like to know the numbers for your own knowledge… if your not making adjustments its kinds pointless to even check it I never check ppms especially if your only using a 3 part from 1 manufacturer u should be the same or gradually going up or down according to amount u did last time it doesn’t change day to day as long as you shake your bottles well and measure accurately you should get close to the same number every time 50 to 100 rpm away is no big deal when your in the 800 to 1000 range

For my own knowledge and to make sure I’m not overfeeding. I had a couple babies in veg and it has been at least six weeks and I tested the run off after feeding a light dose and the runoff was at 2300 PPM. Obviously I should have waited longer before feeding nutrients. Soil still had plenty. Also when I add cal-mag 2 my Trio it increases my PPM a lot. So even if I follow the trio chart adding cal-mag or anything else if needed fluctuates my PPM. So in my case I like to know my PPM on everything. Before or after during. I also want to make sure my ppm’s are coming down nicely during flush.

I always added calmag on water only days when using the trio. So it was feed/ water with calmag/ feed. Fox farms runs on the high side with their nutes so I didn’t want to give the added nitrogen on feed days.


Actually give a little bit of cal-mag on my regular just plain pH water days. I don’t know if it’s the trio which I’m not real happy with or the plant. But it seems like it’s been going through cal-mag deficiencies off and on since the get-go. So I just keep a steady flow of calmag going. Since I’ve been doing this I haven’t had any problems. And with the trio I go a little lighter. I just feel safer with a pen

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@BobbyDigital do you PPM your water before you feed and do you PPM your runoff?

Not so much on the input anymore because with Jack’s it’s the same feed from seed to harvest. I measure runoff ppm from time to time just to check for any buildup.

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That’s what I’m getting next is Jacks. But I have to run this Trio out first. Just can’t afford to switch. Can’t wait to get the Jacks it just seems so straightforward

It is. I don’t even need to ph because with the Jack’s and my tap water it settles right at 6.53. I ran fox farms several grows and they work, just a lot more busy work with them. They’re also light on magnesium and without epsom salt, I had a hard time keeping up with the plants magnesium demands. You will need to check runoff ppm every time you water or feed because the salts can buildup real quick. That’s also why it’s important to follow their flush schedule.

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Couldn’t agree more. Everything you said * 100. LOL. When I was doing my own little nutrient concoction of a try hardware store fertilizer hydrogen peroxide molasses Epsom salts the plants were doing outstanding plus I had a few of those in Jobe plant sticks you stick in the dirt. LOL as soon as I switched to the trio nothing but problems. And that’s why I keep adding cal-mag every water or feeding. I actually started adding a little more Epsom salt again. Do you use Silica?

I do now. I didn’t at the time I was running fox farms.

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Started using silica the last 3 weeks . As we were talking last night about batteries and pens. Definitely have to stop by the store today and grab batteries. Hopefully when I can switch over to Jack’s I won’t need to use my pen as much. No wonder yours has lasted two plus years :slight_smile: and half of my tent is in late flower and I’m having some humidity issues. Got to deal with that when I get home. Thank goodness it’s fun stress :slight_smile: do you know anything about humidity?


I just finished my first full grow with Jack’s. All other grows have been with either fox farms, roots organics or kind soil.

I’ve tinkered with keeping my grows in the perfect VPD but it was just too much work. They do just fine at around 50% humidity the whole grow and that’s about where my house sits all year.

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By the way I think my tap water is 7.5 or 7.8 can’t remember exactly. It would be nice not to have to mess with my pH either. I hope your first grow with Jack’s was a success. I just want to try to avoid the rot if it all possible. Don’t we all :slight_smile: during the day with the lights on everything’s great. Low to upper 40s. Temp 74 to 80. At night is a different story. Humidity 55 to 65. Temp 62 to 66. So if heat holds more moisture why is there more humidity at night with the lights off? I live in the Pacific Northwest. Gets a little wet up here. LOL

It went real well. Got 15oz from 2 plants. Would have been 17oz but lost 2oz from mold due to a dry tent mishap.

As you get closer to dewpoint temps your humidity will increase. Are you ventilating while lights out?

With your tap around 7.5-7.8 you will need to ph down if you’re adding silica. Silica is going to bump that up to probably close to 9.


Noooooo not the mold. I’d be super happy with that amount. I’ll be happy with quarter of that :slight_smile: I’ve got clip on fans and I have them on a timer. They’re on at night but every two hours they turn off for 30 minutes. I will change that when I get home see if that makes a difference. I just don’t want the fans burning out sooner than later. But I also don’t want the mold. And yes on top of the headache from the trio I noticed the silica has added a change to things.

The mold came from the plant collapsing in on itself while drying and prevented the large colas in the middle to be blocked from air flow. I should have removed the large colas and dried separate from the whole plant.

A lot of people use silica for ph up. Are you not exhausting your space? Are you in a room or a tent?

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