Ounce of prevention re: high ppm

Hi all - my runoff ppm without nutes is between 2,500 and 3k after 5 weeks and ph drops from 6.5 to 6. My q is should I flush or what thoughts have you? I think everyone seems healthy, but I’m hoping y’all can help me head off an issue. Straight love is fine too :innocent:

• Strain: ILGM AutoBruce Banner and Runtz. 35 days from breaking ground

• Method: Soil - FFOF with a HF center for the seedling

• Vessels: 5 gal. fabric, planted directly

• PH of Water, Solution, runoff: 7.7ph tap, FF ph down to 6.5 in. 5.9-6 out

• PPM/TDS: here’s the issue. Im getting 2500-3000 ppm without adding nutrients. I was adding cal-mag and silica til a week ago when I first got these values.

• Indoor - 2’ x 4’ x 7’ tent

• Lighting system: Kind X420 at 75%; 16” from canopy; PPFD ~570; DLI -42; 20/4 cycle

• Temps; variable this time of year. Sticking to vpd as much as possible

• Humidity; Following VPD values mostly ok

• Ventilation system; The tent is in a utility shed that is lightly insulated and has a portable heat/ac unit. Inside the tent is a carbon filter with exhaust fan (off) and two small fans to circulate.

• AC, Humidifier, De-humidifier: Humidifier sadly has no auto-shutoff so it’s a pain to manage.

• Co2; No

• Age: 1/10/23 - 35 days

Runtz (Serena)

Bruce Banner (Venus)

Thanks everyone!!

Quick edit: I gave 2,500ml just before the pics.


The twins look great :tennis:

Looking good so far. I get why you’re concerned though. Five weeks in that soil should be somewhat depleted and you want a bit higher pH runoff. I grow in coco so I’m not much help, but I’ve seen both issues come up more than once with FF soils so I’m sure someone can help you out.


Unless they say they are not happy I would keep on just doing what your doing till it goes down. Do yo have a 500 or 700 ppm meter ff I think is 700.




Looking healthy and odd the PPMs are that high for 5 weeks. It’s not uncommon for FF mediums to be that high straight from the bag and on a positive note the organic amended nutrients are more gentle than synthetic based fertilizers. You could always increase your run off to lower the PPMs :love_you_gesture:

1 Like

What was PPM of calmag and silica solutions?
Did you water to runoff or stop when soil moist.


Thanks all!

@beardless I didn’t measure that. I stopped giving it a week ago when I first saw the high values. The water is about 200ppm or so. I have been increasing the water gently - basically every other day. I’ve just starting watering to about 10% runoff. I think twice. They are 35 days old.

@DRsDank I don’t know re meter, I think 500 though since it’s a cheapo ppm meter. That’s all it does. I have an Apera meter for ph. I didn’t realize the scale difference, but if my meter is a 500 and FF goes by 700, do my readings mean even higher? Seems like the reading is what it is in the runoff regardless of the soil scale, do I have that wrong?


The video isn’t for the meter, I like what she says about everybody talking with each other and manufacturers knowing which scale to use.
Sounds like EC is the standard. This is what I’m spending time this week trying to learn better.


Hope this works. Read this. There are many more on the forum also.


EC is supposed to be the universal measure. Like GMT. It is nice when nutrient lines provide both target EC and PPM amounts and the scale used for PPM. Jacks being Jacks provides all three EC / 500 & 700