DWC help requested

This is my second attempt at DWC. My first started off with a blast but ended with nute lock about 3 to 4 weeks to finish. After speaking with Emerald Harvest Nutrients they sent me a feeding chart geared towards DWC. Needless to say I was over feeding. Well, im following their chart and I’m seeing the start of nute lock. I.e. I adjusted ph to 5.8 with every water change. Which I do every week. 12 hours later ph is in the low 5s to high 4s. Below is the support ticket.

  • Tangie’matic and Blue Dream’matic by FastBuds
  • Method: Hydroponics
  • Vessels: Buckets, 5gal Black. 6in net pots with rinsed clay pebbles. Dual air stones in each bucket. Air pump is outside the tent.
  • PH of Water, I start with 6 to 6.3 for veg 5.8 for flower. Measured with Apera PH60. Checked monthly for calibration.
  • PPM/TDS 510 ppm for Tangie’matic 150 for blue dream. Measured with HM Digital Aqua Pro
  • Indoor
  • Light system FGI Light Panel 700 at 50%
  • Temps; Day, Night 78/63
  • Humidity; Day, Night 50/60
  • Ventilation system; Yes, Size 6in hard pipe
  • AC, central air
  • Co2; No
    Water temp day/night. 70/65
    Emerald Harvest Nutrients
    While getting my numbers for the ticket, it seems blue is coming back around. Ppms are down and ph is where I left it this morning. However Tangie’matic is still stalled. Ph is down and ppms are the same. I had done some research on my on and had given them plain water over the clay pebbles. I’m assuming this helped rinse the salts away. O yeah, I also us SLF-100 an enzyme thats supposed to help with salt build up.
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This is why I plant same strain each grow. It makes things complicated. Different strains grow different rates and food changes.
This is also why I do DWC: dumping all the nutes, sterilizing and refilling is easy.
Suggest you check PH daily and change nutes every 4 or 5 days.

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It kinda sounds like the stuff you are using isn’t really well buffered. Are you starting with R/O water?

I use the GH Flora series and with R/O it puts the solution in range with no adjustment. Of course when I add anything like silica or Superthrive it drives it out of range then. Plus; any solution that you are having to modify the PH of will drift over time. Like @tanlover442 said: monitor and change frequently. Florakleen is a good product and hydrogen peroxide should be used between changes.

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I do monitor twice a day. I use filtered rain water with a PPM of 14 or less. When I do my water change, I dont have to adjust the ph much. Maybe a drop or 2. Up until now the ph would rise as the ppms would drop after the first 24 hrs. I’m assuming this is the plant using the nutes faster than water?

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That’s actually how best to determine the nutrient load. If it goes down, set a higher TDS. If it goes up, lower the concentration. Data taken before adding water.

For example, my rez is at 1,000 ppm. 24 hours later I’m down to 800 ppm and 2 gallons of water. The plant is using more nutes and lowering the solution concentration. So I up it to 1,200 after adding water and repeat. Once the TDS stabilizes, that’s my target. This value will change as the plant matures.

Look up VPD for cannabis and download the chart. It’s helpful too.

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Heres how I’ve been doing this so far. Every Saturday I start with a clean bucket add my water. 4 gals to be precise. Then I add my nutes following the sheet I posted a pic of. They are just now at the point were they need water between changes. So when water is needed I add plain water and pour over the clay pebbles. Bringing water level back to 4 gallons. These are stand alone buckets. No reservoir. I looked at the VPD chart. We are going into transition so I think humidity is good. 50 to 60% at 78 degrees? Also Tangie’matic is a week behind blue. They both are autos

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I test and adjust daily

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I would test and adjust daily.

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I was using GH Flora series also with RO and it was very stable and easy to adjust. (If it was even necessary). Recently I switched to Jacks powder to save on the cost of nutes. It also seems to be very stable for me in my RDWC system.

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I use GH Maxi series bloom @1/4 strength in RDWC. Just like @Myfriendis410 said, the plants will tell you what they need, IF you listen. When you have it dialed in, your water level will drop, but PPMs stay about the same. If PPMs went down, you need more nutes. If PPMs go up, you need to cut back on nutes. With DWC, if you screw up, just dump it out and start over

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3 White Widow Autos. That’s a 32 inch wide door in the back ground. Seeds popped on 4/19 and 4/20 and flowering started on 6/3. 6 week of flowering.

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