Nutrient burn yet visible yield bump, wtf?

Alright, so long story short - I run an aero setup that is mostly automated. Girls are in Week 6 of Flower, fed by a 40 gallon res on timer as well as lights, temp, etc... Two days ago I changed the res and bumped my PPMs from 1600 (Week 5) to 2000 (added 'overdrive' by AN). Then Yesterday morning I had to go out of town for something and did not get back until around 6pm tonight. The 30 girls I have fed by the res normally drink a lot. But when I got back 30 hours later, the res was 10 gallons lighter and my PPMs shot up to 2650 (they drank a lot of water without using the nutes proportionally). Fine - no biggie, a little nute burn on fan leaves. But the surprise was that the buds gained noticeably in size and frostiness in just 30 hours. Now I'm pretty good at math and I can figure out that from a 40 gallon res at 2000 PPMs I'm left with 30 gallons at 2650 PPMs, they drank 10 gallons of RO water ingesting almost no nutrients. So what's with the best gain I've seen all flower? And nute burn did not appear to stun them at all either.

I'm thinking of trying something new now in terms of throwing 3-4 days of pure RO water feed every two weeks in flower. Anyway, anyone else had any similar experiences? Every grow I seem to find something new that I cannot explain using previously acquired knowledge...

p.s. I will post some pics tomorrow when the lights come on so you can judge for yourselves how they look before and after the days in question.

Subscribed. I'd like to see the results. I use soil and like to give my plants a little water before I hit them with nutes, budding or vegging. It seems to work well.

There is no time stamp but I believe this photos are 4 days apart including the previously mentioned 30 hour period:

Pink Lemonade - Before: , & After:

Pineapple Express - Before: , & After:

I am confused here. So your tds went higher, and you observed an increase in size/frostiness greater than expected, so then you want to experiment by doing the exact opposite, 3-4 days or RO water only?

p.s. What is your conversion factor to ppm from EC? I don't think my meter even reads over 2000 ppm. At my .7 ec conversion, I grew c99 at about 360ppm in aero. Almost nothing in the res. I probably could have dipped a glass into the res and drank that all day, 62F, nice cool glass of water. Haha. Quite a contradiction to what you're doing, isn't it? My tap water is 600-900ppm.

Now I'm dwc with a lot higher tds, like 1300-1500, and I always see the best yields and stickiest, most frosty buds with significant nute burn. I basically just gave up on perfect leaves.

harvey m said:

I am confused here. So your tds went higher, and you observed an increase in size/frostiness greater than expected, so then you want to experiment by doing the exact opposite, 3-4 days or RO water only?

p.s. What is your conversion factor to ppm from EC? I don't think my meter even reads over 2000 ppm. At my .7 ec conversion, I grew c99 at about 360ppm in aero. Almost nothing in the res. I probably could have dipped a glass into the res and drank that all day, 62F, nice cool glass of water. Haha. Quite a contradiction to what you're doing, isn't it? My tap water is 600-900ppm.

Now I'm dwc with a lot higher tds, like 1300-1500, and I always see the best yields and stickiest, most frosty buds with significant nute burn. I basically just gave up on perfect leaves.

Click to expand...

Not really doing the opposite but accommodating what they appear to do on their own. 40 gallons at 2000 parts per million and 2650 parts per million in 30 gallons is the same amount of nutrients in different volume of water. That means they drank the water and did not absorb the nutrients. I flush my res weekly. Usually i fill the tank with nutrients and then daily check the PH and add RO water to make up for what they drink. By the end of the week my nute count is usually half of what it was when I started. So they only absorb half the nutes I give them. Following logic, I give them half as much nutes but then they show deficiencies. Trying to find the ever-changing sweet middle where i keep them happy without wasting spendy nutes.

You're at that time where the buds start doing that. Also, that Overdrive is no joke! I love the stuff.

Well, how do you think they'd respond if instead of adding RO water only, every few days add water and a calculated amount of nutes? It is a little more work that way though.

That's what I do. Solution level drops, then I add RO water, measure tds, then calculate what to add to attain my target tds. Some strains I keep the same tds for 8 weeks, some strains need a tds curve, some no nute changes using this method, some 2 nute changes.