Hello all. Ive been growing for about 3 yrs now and i started out dwc and eventually spread my wings and set up a little recirculating system with some nets so i could scrog and all was great…but then i had my sytem torn down and put my old buckets back in action but left my reservoir hooked up with a float valve fill system so that when the bucket got to the designated spot low it auto filled back up. Everything was great…so i thought…i came in one day and two of my plants were very obviously stressed so i started combing over all of my parameters and found nothing wrong.temp was good humidity air checked the reservoir ppm… ph couldnt find anything wrong so i went about my buisness and the next day when i came in one of the plants was done it was dead and the other was like a bleached kinda colr only on the surface so im like root zone and thats where i found my issue. In my resevior the ppm was 1250 which os were i ride the last couple of weeks of flower before i flush and i also doble up on phosphorous and potassium but down inside the bucket the ppm was 3500 and of vourse when i put my eyeballs back in my head drom them popping out at the site of such a large number i dumped all the bucketa and they were all the same. My queation is this… how does the ppm go drom the reservoir 1250 to bucket …same water and all to such a large number. Any comments on that ? Thanks in advance.
I ran an RDWC system almost just like what you’re describing. One tote housed the nutrients and would just flow through pvc into 3 buckets. 2 had plants, the final one had a water pump that pushed the water through into a water chiller that dumped back into the tote.
I experienced almost the exact same phenomenon, although it was my #2 in the lineup plant who got shocked and died on me.
In hindsight, I should have known this would be what happened without wavemakers in each bucket and the tote to keep the mixture constantly mixing at all stages of the flow.
Dense stuff settles out, even when water is moving. I have a system like this designed at my job quite intentionally to allow for settling. Dirty water gets pumped into a 200 gal tank, then from that into a 2nd 200 gal tank, then into a sink, down into a 2” pvc drain with a 5gal bucket as the final settling point, then more 2” pvc to the main sewer line. The first tank obviously fills up much faster than the rest. But the second tank also accumulates sediment even when the first isn’t full, and the 5gal bucket also accumulates debris even when the other two aren’t full.
Naturally you’re experiencing this drop-out. The current isn’t strong enough in your system to recirculate all of the nutrients - some of them are settling into the buckets and just layer up at the bottom. The topmost water will continue to circulate, or in your case without circulation it will just settle and keep on settling. If the reservoir is the only thing you check PPMs in, and there is no back flow into the reservoir, it makes perfect sense that your overall ppm would rise due to the nutrients that fell out of the solution.
Daaaammmnnn son. Ganja Scientists 
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Thats a beautiful explanation . I appreciate that. That also explains why a 5 gollon jug of flora micro is so much heavier than a 5 gallon bucket of water i bet because there’s about a 8 to 10 lb diffeeence between the two. Awesome thanks again.
Absolutely. A 5 gallon bucket of paint is about 20% heavier than water. A 5 gallon bucket of ceramic glaze is about 50% heavier than water. I think nutrients will vary heavily, but I’ve had some anywhere between 10 and 40% heavier than water. You can measure those sorts of things with a gravity cup, but there’s no real practical reason, just scientific curiosity mostly. I operate in specific gravity for work (ceramics), and have to remind myself my 42 pounds of water (5 gal) is often much heavier - 62-67 pounds - by the time I’m done with it.
Same thing applies for nutrient water. A 27 gal tote of just water is already about 225 pounds when completely full. Add an additional 20% in nutrient weight and you’re looking at 270 pounds. On a smaller scale, a 5gal DWC bucket probably should be around 30 pounds (assuming 3.5 gal to get to the bottom of the net pot with a reasonable air gap) and after nutrients are added, it’ll be around 35 pounds. After the settling phenomenon, you could easily end up doubling that weight as the solids accumulate in the bottom.
Keeping track of the weight of your bucket may not be the most practical, but if you can lift it with ease when it’s freshly cleaned, you can periodically try to pick it up - when it becomes a struggle, it’s probably time to change the water out totally.
Graysin is correct in the sense you need a circulation pump to n your tote to keep you nutes mixed up and not settling to the bottom to keep it oxygenated. You like yo keep the EC the same in bucket depending on stage.One circulation pump and 1 pump to pump it out, I also like to have a little tank before it dumps back in to test