Greengrouch
Well-Known Member
Yeah, first two weeks of veg I only needed to add a little ph up once and that was at .8ec
Wanta try RDWC in a 4x2
- Thread starter SoggyCashew
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marzig
Member
I really didn't see how volume could buffer ph swings either but I had to ask.
amneziaHaze
Well-Known Member
If you think about it the air pump is 24h on and co2 from air makes the water 7+
marzig
Member
What's your waters starting ec? I'm using ro and my current ec is .6
Greengrouch
Well-Known Member
8ish I use half RO half tap, silica then ph to 6ish
Good point. I agree. With a surface area that small, you've got to get under one of the plants to do maintenance vs working unobstructed in the external bucket.
Good to know. Thank you.
Something that has more mass tends to take longer to change state than something that has less mass.
In terms of cannabis growing and res size, a 50" plant in a 3 gallon bucket will impact the conditions in a 3 gallon bucket more quickly than it will impact a res with 26 gallons of nutes.
Similar setup. I've dropped one plant for a few grows but my canopy just doesn't cover the 2' x 4' area so I'm going to switch back to 2 plants.
That was my last decent grow (I poisoned my most recent one by adding too much H2O2 to the humidifier water. H2O2 stops algae and it is effective at damaging plants!).
I'm making a new res top for my next grow. I use a veg light so the plants are very compact. Add in topping and LST and I'm determined to get two plants in there.
marzig
Member
At first I thought the only thing volume would affect would be temp swings. After thinking about it, I realized I wasn't taking into account a living organism in the equation. The plant is taking a smaller percentage of dissolved solids out of 26 gallons than 3 gallons.
Yup. That "big bucket", as I call it, holds quite a bit of nutes and that makes it easy to go a few weeks between res swaps.
The plants do exude chemicals as well as take them in. With the bigger res, there's more water to dilute the exudates.
I've attached a couple of PDF's on res maintenance. Bugbee is informative, the CannaStats is more of a "how to" but the Bugbee paper explains why adding back nutes can cause issues.
The biggest thing for me was getting my head around the idea that it's OK to let EC drop from, for example, 1.6 to 1.0 (typical values for flower). I had always thought that the res should be close to 800/500 (PPM) but even at 500/550, there's still a hell of a lot of chemicals in the res…and the rest of them are in the plants.
marzig
Member
Very interesting information in these PDFs! I know I don't have anywhere near the reservoir capacity for my canopy size that they recommend. Since it's early in my current grow I'm considering a new strategy.
I think I'll try doing straight RO water add backs until my PPMs drop to between 65 to 75% or I'm chasing pH too much. I've got nothing but time and the money spent on nutes isn't a problem for me either.
I'm excited to see how this works out. If I like the results at the end of this grow I may consider changing over to RDWC. This will give me plenty of time to figure out how to safely contain any overflow if I were to have roots cause a blockage somewhere in the system.
You're very welcome. I found then helpful and just like to pass along the good info.
Aha - a man of leisure and wealth!
The cost of nutes isn't a big driver once you get away from the "change it every week" and/or bottled nutes. I was in the mode for the first grow or two until I toned down the "helicopter plant daddy". Now I'm just mildly obsessive!
RO add backs have worked well for me. I measure light levels daily but sometimes can't be bothered to check water levels. I use a 5" cork with a steel ruler stuck in it = the Rubber Ducky approach.
Yup, that's something to watch out for. Companies like PA Hydro and Current Culture (primo gear) use large PVC pipes, in the region of 3" I think.
The external bucket does make life a lot easier. My res top is 23" x 39" or something like that so I've got plenty of room to access the res but an 8 gallon bucket is going to be overgrown pretty quickly by a big plant. And my sense is that hydro makes it easy to end up with a vary large plant. I do not have a green thumb (the only other thing I've grown is "old") but I've ended up with some pretty big plants.
amneziaHaze
Well-Known Member
You have 2 diaries of mine with every day ppm and ph test.one is in 7-10L other is in 70L
Rocket Soul
Well-Known Member
If i were to go for one of these fancy, fastest growth type systems id be looking at making a PPK a la Delta9. Im wary of any system where one pump failure could mess up the whole grow. Any machine will eventually fail, how much it affects your grow dependa on your system and if you can build in safety features the better.