Trying to understand EC in RDWC

[SwoleGrow]

I understand EC and as the plants feed it will fall. But what I’m not understanding is why is it fall so much?
Ill give my current scenario
A week ago I did a partial system flush because EC had fallen from 1.2-1.3 to 0.9, water level was falling and ph was static. I replaced the 7 gallons flushed from the system with a nutrient solution that was 0.2-0.3 EC higher than what was flushed and that raised the EC of the system to 1.3-1.4.
Next I refill the topoff res with an EC that’s 0.2 higher than the system with hopes of stopping it from falling so fast. It did slow it down but it still fell from 1.3-1.4 to 0.9-1.0.
Now this is where I’d normally partial flush, refill from topoff res with higher EC. Res change with 0.2 higher EC than system then wait and see the results, but this time I didn’t do anything. I let the plants eat and do their thing only topping off the res with full strength according to their feeding and after 3 days the EC is holding at 0.9 or 640-650 ppm.
Why is this???
What am I missing here?
The plants aren’t showing any problems and growing nicely. I’m just trying to understand the fall in EC then the level out and stability at a lower EC.

 

[Deadstill]

Have you seen this chart, yet? Maybe this will help..

 

[FourthCity]

Have you seen this chart, yet? Maybe this will help..

View attachment 948380

Good chart.

 

[SwoleGrow]

Good chart.

yes that’s what led me to upping EC by 0.2. Why would it fall from 1.3-1.4 to 0.9-1.0 and stay there for 3 consecutive days?

 

[Deadstill]

yes that’s what led me to upping EC by 0.2. Why would it fall from 1.3-1.4 to 0.9-1.0 and stay there for 3 consecutive days?

Probably just not hungry and/or eating and drinking at the same rate. If they look happy and healthy, it's a good thing.

 

[Terpz719]

Have you seen this chart, yet? Maybe this will help..

View attachment 948380

Anyone have a link to something similar for DTW?

 

[SwoleGrow]

Probably just not hungry and/or eating and drinking at the same rate. If they look happy and healthy, it's a good thing.

Yeah they look perfectly ok to me. Was just trying to get a better understanding.

 

[SwoleGrow]

Probably just not hungry and/or eating and drinking at the same rate. If they look happy and healthy, it's a good thing.

So, (if you run rdwc) you wouldn’t have a prob with watching the ppm fall from 900’s to 600’s and still replace what they ate in the topoff res abd not have an issue? That’s what I’m doing btw

 

[pr3tti]

So, (if you run rdwc) you wouldn’t have a prob with watching the ppm fall from 900’s to 600’s and still replace what they ate in the topoff res abd not have an issue? That’s what I’m doing btw

How do you know what they ate to gauge what to top-off? Top-off cal-mag or all-in-one? What ratios? Did plant consume cal-mag more or all-in-one more kind thing?

 

[SwoleGrow]

How do you know what they ate to gauge what to top-off? Top-off cal-mag or all-in-one? What ratios? Did plant consume cal-mag more or all-in-one more kind thing?

I have a measuring stick marked off by gallons that tells me how much they drank out of the topoff res. Topoff using GH nutes
5m/g armor si
10m/g flora blend
1m/g floralicious plus
5m/g diamond nectar
3m/g micro
6m/g bloom
5m/g cali magic
This will have me at 1.4 EC in topoff res & 0.9 EC in the system.
My thinking leads me to believe 0.9 is low and they don’t have enough to eat because the initial EC of the system started at 1.3-1.4 and within a couple of days it was 1.0-1.1. Few days later it settled at 0.9 where it’s been for about 4 days.
I have bluelabs guardian controller reading the system in ppm/700 and I can watch them fall. I also have the ph controller and it’s set to read in EC and keeps the ph where I set it when the system is functioning properly. As of now with the EC & Ph slowly falling I have the topoff res ph at 6.5 to keep the system ph acceptable. It’s currently 5.9.
8x8 sealed & C02 @ 1500ppm was @ 1200ppm when I first noticed the falling EC & Ph.
Plants are looking healthy