Tds/ppm Confusion

[Greengrower8]

Recently in this grow I began measuring ppm’s in my dwc buckets, which is something I haven’t done before. I understand the basics of it and, when starting with new, clean (RO) water, adding nutrients to a desired ppm level is easily achieved. However, how are such weekly adjustments made to the reservoirs if they aren’t flushed with new water? I realize it’s recommended to change the water weekly in a dwc setup such as mine, but honestly, I think that’s overkill, especially when you don’t see any major pH spikes or drops or other visual problematic cues. It’s also a huge pain in the ass when you have 30 buckets. I do think the water should be changed eventually, although I’ve still had success without changing the water more than once throughout flower.

Anyway, my lights went 12/12 about 2 weeks ago and the reservoirs are due for a nutrient increase. They are running about 1100 ppm consistently since their last feeding. A few of them are a bit larger, drank more and had to be topped off a few times so they are at around 850 ppm. I only use GH trio and Hydrogaurd. The last feeding to continue transition from veg to flower (with clean RO water) at 1100 ppm was achieved by adding 35/35/35ml of GH trio and 7.5ml of hydrogaurd per bucket.

How am I supposed to make these buckets 1300 ppm from the levels they’re at?

In the past, totally ignoring ppm’s, I would just add the nutrients according to my chart - at this point, early bloom calls for 7.5/2.5/10ml of GH micro/gro/bloom per gallon. I always go half strength, so, in past grows, I would just add 15/5/20ml of GH trio per bucket. Obviously, this is considerably different when you add according to certain ppm levels. Like I said, I had to add 35ml of all 3 per bucket to get to 1100 ppm. So, using clean water, adding 15/5/20ml per bucket is gonna be no where near 1300 ppm. And it’s even more confusing if I’m trying to go from 850 or 1100 to 1300 ppm. And simply adding 200ppm or whatever to the existing reservoirs seems like spitting in the ocean.

Please help!!
Thanks!

 

[Jack og]

Well here a a very good old article but relevant to your situation.

https://www.420magazine.com/community/threads/dwc-quick-question-about-ph-and-ppm.253763/

 

[Jack og]

Dwc is a bear it’s why folks do a ebb and flow or counter flow dwc, so that you deal with a reservoir as opposed to each individual bucket. When you have the qty of buckets like you do, it’s can be a pain In the ass keeping up.

 

[Greengrower8]

That’s an interesting thread, but it still leaves me wanting answers. I still don’t know how much of the nutes to add to raise the ppm any specific amount. Also, the proportions change every week. So the ppm of one group of nutes one week is not gonna be the same for the next week. It would be a constant trial and error game adding and subtracting nutes. Some of the plants drink a quart a day and some of them drink barely a quart a week so the plants that barely drink anything, the ppm never changes, but they are clearly growing well. The plants don’t leach the nutes out of the water, they drink the water which in turn gives them nutes, right?? So, how are these plants feeding if the water level barely changes? I never understood this, yet the plants grow fine. I don’t want to change 30 buckets every week to adjust the nutrient level. I still don’t understand how the proper proportion of nutes at a specific ppm level is to be achieved without starting from zero.

 

[4plant]

I’ve found in dwc in-between res changes the best way to maintain a good ec is to addback only what is in high demand at the time with the amount of water you need to get to the right level. If your in mid veg and have gone from 4 gallons to 3 in your buckets you need to add 1 gallon back right? add it with only nitrate nitrogen at say 200ppm. You won’t maintain a ppm of exactly 1100 or whatever but it’s more important to get a boost of what you actually need than to just maintain a specific number. If you really want the numbers to add up than mix a extra bucket at your desired ppm and use it to refill

 

[Jack og]

I’ve found in dwc in-between res changes the best way to maintain a good ec is to addback only what is in high demand at the time with the amount of water you need to get to the right level. If your in mid veg and have gone from 4 gallons to 3 in your buckets you need to add 1 gallon back right? add it with only nitrate nitrogen at say 200ppm. You won’t maintain a ppm of exactly 1100 or whatever but it’s more important to get a boost of what you actually need than to just maintain a specific number. If you really want the numbers to add up than mix a extra bucket at your desired ppm and use it to refill

Like a reservoir, use that as the known mix for add backs but his issue is that they all range diff. It’s why maybe make it into a drain to tanks and pump back so that no matter what they drink the solution would be equal irrespective of uptake , then simply makeup solution to add back reservoirs to optimum. Kinda a crude ebb and flow but still a dwc. Manual valves to drain all to central pump and recirc back in once a day or multiple x a day and adjust. 1x a day or 2

 

[Greengrower8]

Ok. I have a plan. Here is the ppm schedule I use (this is from a well experience grower):
Veg
Week 1: 600
2: 900
1200, 1500, 1800 (hold there if vegging longer than 5 weeks)
Flower
1000, 1300, 1600, 1900 (hold there)

If there is any input about this, I’m all ears cuz this is the first time I’m measuring ppm at all. I’m already 2 weeks into flower. I will just change the water a few more times. And by the time the ppm is to be held steady at 1900, they will be all be drinking a gallon a day and it will be easy to add back the same proportion of nutrients during top offs, so I won’t have to change the water after that point.

Honestly, the more mind blowing thing for me is how much more nutrients I am adding to adhere to this ppm schedule. Like I said, previously at week 2 of flower, according to my recirculating nutrients chart, I would be adding 15/5/20ml per bucket of GH trio (and I got killer plants this way). The buckets I just changed for flower week 2 received 40/15/50ml per bucket and they are still only at around 1100ppm. This is a huge difference. Don’t get me wrong, the plants seem to love it. I have no complaints. Of course, these are all different strains from previous grows and I had been using tap (well) water up until this grow when I got my RO system. So it’s hard to compare.

Thanks for all the input guys!

 

[Rootbound]

Ok. I have a plan. Here is the ppm schedule I use (this is from a well experience grower):
Veg
Week 1: 600
2: 900
1200, 1500, 1800 (hold there if vegging longer than 5 weeks)
Flower
1000, 1300, 1600, 1900 (hold there)

If there is any input about this, I’m all ears cuz this is the first time I’m measuring ppm at all. I’m already 2 weeks into flower. I will just change the water a few more times. And by the time the ppm is to be held steady at 1900, they will be all be drinking a gallon a day and it will be easy to add back the same proportion of nutrients during top offs, so I won’t have to change the water after that point.

Honestly, the more mind blowing thing for me is how much more nutrients I am adding to adhere to this ppm schedule. Like I said, previously at week 2 of flower, according to my recirculating nutrients chart, I would be adding 15/5/20ml per bucket of GH trio (and I got killer plants this way). The buckets I just changed for flower week 2 received 40/15/50ml per bucket and they are still only at around 1100ppm. This is a huge difference. Don’t get me wrong, the plants seem to love it. I have no complaints. Of course, these are all different strains from previous grows and I had been using tap (well) water up until this grow when I got my RO system. So it’s hard to compare.

Thanks for all the input guys!

Seems like very high PPM's. I never go above 700 in veg and flower in unamended promix or coco.

 

[Greengrower8]

Seems like very high PPM's. I never go above 700 in veg and flower in unamended promix or coco.

These are ppm’s for a recirculating hydro (dwc) system, not promix, coco, etc. I’m sure there’s a difference, although I don’t know what the values should be in any type of soil.