razingthebar
Member
Noob, but studying hard.
ISSUE: A couple days before the flip my pH started crashing from about 6 down to 4 (sometimes lower) in about 12 hours. EC/PPM would spike in same time period.
RIG: small (5 gal) DWC with top down and two air stones (air pump is outside the grow tent), Humboldt Seed Co. Magic Melon and Collie Man Kush (two of each) sharing same res, RO water and (prior to these issues) changing res about every 7-10 days. Lotus Nutrients (currently Bloom and Boost).
Day 12 of Flower as I write this. Plants look healthy overall (a little nute burn on a few tips here and there).
Right up until the flip I was running 1,100PPM (less than nute company suggestion) with pH only increasing slightly over time. About the time I noticed nute burn on the tips of only one strain the pH crash started and PPM spikes. I tried res changes and lowering the PPM, but still ended up with crashes and spikes. Roots are nice (no slime, no smell) and I'm using hydroguard (2ml per gallon), so I don't think it's root rot.
I have the chart from 420 Mag. that people keep posting, which suggests lowering EC and doing res changes until the issue stops. So far I'm down to 400 PPM and still having the same issues.
Then I saw someone quote this and wondered if this is the issue:
As plants uptake water they do not necessarily uptake nutrients at the same rate and as this occurs, the plants might be drinking lots of water but not eating much food. The result is that in a matter of hours, as the water is depleted, the concentration of the nutrients in the bucket can reach toxic levels. So it is critical to always under feed your plants in this system
Up until this started happening I was topping every day with nute water at a lower PPM to bring them down (e.g., if I wanted 800PPM and res rose to 880PPM over a day, I would add 600PPM water to lower the PPM back to about 800PPM). The quote above suggest that while the PPM was rising, some nutrients may have been consumed while others not, then when I added the nute-water top-up I was adding MORE of the nutes that were not consumed, raising those particular nutes to (maybe not toxic, but) bad levels which causes the pH to crash b/c the built-up nutes are acidic. In a sense, I've been chasing my own tail if that's right...
Is the cure as simple as topping up with plain, balanced water (no nutes)?
But maybe I'm over-thinking this one. (I also recognize I may have an issue caused by two strains in one res - if one wants a LOT of nutes and the other very little, that could be causing one to burn and the other to be deficient or at least leeching nutes back into the res.)
Many thanks for your thoughts
ISSUE: A couple days before the flip my pH started crashing from about 6 down to 4 (sometimes lower) in about 12 hours. EC/PPM would spike in same time period.
RIG: small (5 gal) DWC with top down and two air stones (air pump is outside the grow tent), Humboldt Seed Co. Magic Melon and Collie Man Kush (two of each) sharing same res, RO water and (prior to these issues) changing res about every 7-10 days. Lotus Nutrients (currently Bloom and Boost).
Day 12 of Flower as I write this. Plants look healthy overall (a little nute burn on a few tips here and there).
Right up until the flip I was running 1,100PPM (less than nute company suggestion) with pH only increasing slightly over time. About the time I noticed nute burn on the tips of only one strain the pH crash started and PPM spikes. I tried res changes and lowering the PPM, but still ended up with crashes and spikes. Roots are nice (no slime, no smell) and I'm using hydroguard (2ml per gallon), so I don't think it's root rot.
I have the chart from 420 Mag. that people keep posting, which suggests lowering EC and doing res changes until the issue stops. So far I'm down to 400 PPM and still having the same issues.
Then I saw someone quote this and wondered if this is the issue:
As plants uptake water they do not necessarily uptake nutrients at the same rate and as this occurs, the plants might be drinking lots of water but not eating much food. The result is that in a matter of hours, as the water is depleted, the concentration of the nutrients in the bucket can reach toxic levels. So it is critical to always under feed your plants in this system
Up until this started happening I was topping every day with nute water at a lower PPM to bring them down (e.g., if I wanted 800PPM and res rose to 880PPM over a day, I would add 600PPM water to lower the PPM back to about 800PPM). The quote above suggest that while the PPM was rising, some nutrients may have been consumed while others not, then when I added the nute-water top-up I was adding MORE of the nutes that were not consumed, raising those particular nutes to (maybe not toxic, but) bad levels which causes the pH to crash b/c the built-up nutes are acidic. In a sense, I've been chasing my own tail if that's right...
Is the cure as simple as topping up with plain, balanced water (no nutes)?
But maybe I'm over-thinking this one. (I also recognize I may have an issue caused by two strains in one res - if one wants a LOT of nutes and the other very little, that could be causing one to burn and the other to be deficient or at least leeching nutes back into the res.)
Many thanks for your thoughts