RDWC PPM QUESTION NEED A QUICK RESPONSE PLEASE!

legitroller · 2025-06-17T12:08:21-0600

So my grow is going awesome, I'm under 900 ppm, less is more on nutrients, great progress, will update my other thread later once I have time. So I am about to incorporate Fox Farm Open Sesame. Now, I have measured my ppm of just water, which is 75 ppm. I started by adding 1/4 tsp to a gallon of water, which took my ppm to 205. Now I subtracted my start ppm from that and end up with 130 ppm. Now my res is 20gal, I'm already at 873ppm on regular nut, so adding this will kick my ppm through the roof. What shall I do? Or should I not use it, order some dry Koolbloom, and just use that?

My feed schedule

FloraMicro 5.7ML per gal 20gal
FloraGro 6.6ML per gal 20gal
FloraBloom 3.8ML per gal 20gal

Updated Photos

Thurston · 2025-06-17T12:28:47-0600

Sorry but I only use EC and not PPM readings. As you said in your first statement, less is more. Recommend to never exceed 1.2 EC in RDWC no matter what you add but your mileage may vary. Watch your plants for signs and adjust from there.

Delps8 · 2025-06-17T12:54:43-0600

When you add chemicals to the solution, it will increase EC. Will it be enough to push the plant into toxicity? We can't tell. The plant will tell you when it's too much, so going from 873 to ~1100 might put you into the toxicity range or it might not. VPD can be a major factor in hydro so you could still be in the sufficiency range or you could be in "luxury consumption" which is sufficiency but on the edge of toxicity.

Something to keep in mind is that the goal of nutrients is to give the plants enough chemicals to be in the sufficiency range. That's all. More than sufficiency puts the plant into toxicity.

I grow in a res the holds 28 gallons and I max out at about EC 1.6 (800/500) but I also keep VPD at 1.0 in veg and 1.2 to 1.5 in flower.

legitroller · 2025-06-17T14:19:39-0600

Thurston said:
Sorry but I only use EC and not PPM readings. As you said in your first statement, less is more. Recommend to never exceed 1.2 EC in RDWC no matter what you add but your mileage may vary. Watch your plants for signs and adjust from there.

I try to use EC but my hanna hi show 1234 for EC so I use PPM

legitroller · 2025-06-17T14:41:57-0600

Delps8 said:
When you add chemicals to the solution, it will increase EC. Will it be enough to push the plant into toxicity? We can't tell. The plant will tell you when it's too much, so going from 873 to ~1100 might put you into the toxicity range or it might not. VPD can be a major factor in hydro so you could still be in the sufficiency range or you could be in "luxury consumption" which is sufficiency but on the edge of toxicity.

Something to keep in mind is that the goal of nutrients is to give the plants enough chemicals to be in the sufficiency range. That's all. More than sufficiency puts the plant into toxicity.

I grow in a res the holds 28 gallons and I max out at about EC 1.6 (800/500) but I also keep VPD at 1.0 in veg and 1.2 to 1.5 in flower.

View attachment 5469730

I have a hanna hi 98129 pen, which reads PH, PPM, EC Us it always reads in Us 1432 but claims it reads EC so I'm stuck with ppm

RDWC PPM QUESTION NEED A QUICK RESPONSE PLEASE!

legitroller

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