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Tending Your Reservoir for a Full pH Swing and Cleaner Cannabis
- Thread starter Douglas.Curtis
- Start date
Be careful... Watch for lockouts...
I've used a ph drift for years with much success in rdwc. I change solutions once weekly, set the ph on the lower side and let it drift up with ro top offs through the week. Every 7 days drain change solution and repeat. Always a quality product! Kudos for the thread.
Douglas.Curtis
Autistic Diplomat in Training
This is the simple res management Lucas recommended, especially if you don't have access to meters or pH testing.
It's the same place I started with hydro as well. Awesome.
And how many gallons of water/nutrient solution are you changing out every week?
It's system dependent, so would depend on the size of the controller and system.
Yes, I realize it's system dependent. How about some kind of number for a system? Are we talking 50gallons a week, 100 gallons a week, 200 gallons a week?
Douglas.Curtis
Autistic Diplomat in Training
The easiest way to manage is by counting the add-back gallons of r/o. 100 gallons of solution is changed every time 100 gallons of r/o have been used to top off the res.
Starting flower with a 7-10 day window for your pH drift, peak flower will be about a 4-6 day drift before you hit changeout. As flowering progresses, the rate of transpiration and nutrients being used goes up dramatically.
So... 7-10 days for the first 200 gallons (100 gallon res filled, plus 100% addback), with a shortening time span as flowering progresses.
I was asking Blazeoneup how many gallons he goes through? If your changing out your res every 7 days, that is a lot of water and nutrients to change out every week. I recall seeing some of Blazeoneup's grows back in the day on overgrow.
If you are using 100 gallons of RO every week to change out your Res, that's 400 gallons total (waste out put and RO out put), that is a lot of water. (total gallons dependent on ratio RO/Waste rates 3-1, 2-1)
I used to change out my Res every two weeks. These days the most I change out my Res is 1 time per grow cycle. I've also been able to run a system without changing out the Res the whole grow.
I do see a swing in the PH when the water levels drop. I do add back in mixed nutrients. the top offs are most often, RO, RO, Mixed nutes. When the Res gets back to it's starting ppm, the PH goes back to where it started.
This I've figured out over years of growing in hydroponic systems. If some one is new to hydroponics, its best if they change out their res every 2 weeks
Douglas.Curtis
Autistic Diplomat in Training
Yes, the simple res management technique Lucas pushed is quite wasteful, unless you're dumping your res on a garden or something useful. Blazeoneup goes through even more than this, by staying to a rigid schedule instead of counting add-back gallons.
This is why you use the 'advanced' res management methods Lucas pushed, and I've outlined here in this thread. Though it does require being able to test pH and ppm/ec/tds, it saves a LOT of water.
The only 'dumping' you do is with very low ppm water, just before harvest.
Substitute
Member
Read this. Interesting. Do plants experience this full PH swing in nature?
In nature you have clumps and layers of nutes, not homogenous solutions, I'm pretty sure each individual root does its best to interact with whatever dead crab or rabbit pellet it encounters.
Douglas.Curtis
Autistic Diplomat in Training
Nature provides pH changes through a variety of methods, yes. In soil, many exchanges of elements are accomplished in other ways through a living, thriving soil. This is not a discussion about nature and living soil though, we're covering how pH changes affect nutrient absorption in a hydro reservoir. It's a rather specific environment.
Cannabis is remarkably good at absorbing excess elements and many things it has zero need for when forming flowers. This means mistakes in hydro are readily 'noticed' by the end user, because there's literally no way to 'flush' excess or unwanted molecules out. Yes, you can pull out un-used nutrients/molecules. No, you will not be able to pull 'fixed' elements/molecules out of formed flowers. Like the old spaghetti commercials... "Iiiit's In There!"
Cannabis is remarkably good at absorbing excess elements and many things it has zero need for when forming flowers. This means mistakes in hydro are readily 'noticed' by the end user, because there's literally no way to 'flush' excess or unwanted molecules out. Yes, you can pull out un-used nutrients/molecules. No, you will not be able to pull 'fixed' elements/molecules out of formed flowers. Like the old spaghetti commercials... "Iiiit's In There!"
Substitute
Member
I was thinking of starting the plants out at 800ppm. My water is 230, so nutes would make up the rest of that.
Douglas.Curtis
Autistic Diplomat in Training
Sounds like a decent starting point, and 230 is a lot. Start a thread and document the progress with your tap water. I'd love to see the differences between now and when you upgrade to r/o in a few years. You'll be happy to have it saved as well.
This thread details using r/o water and tap is completely out of place. Shoot me a link when you've created your thread, I'll stop by and we can pick up this conversation there.
RO systems capable of 400g + will have a rather large booster pump, which SHOULD reduce waste to ~1:1, which is still a lot, AND they are expensive
Depending on where you live, there are local companies who rent DI tanks to kidney dialysis facilities. Don't know how they would feel or whether there are any legal restrictions for a grower to rent their tanks, then just do an exchange when you see the EC going up
Douglas.Curtis
Autistic Diplomat in Training
Welcome to ICMag!! Great first post!
Wow, this statement is remarkably similar to a response I read on facebork just the other day. How coincidental...
Everything is relative to your own education and experience. I, and everyone around me, said I grew the best cannabis around in 2008.
What a joke that quality was, but it was 'the best' we'd seen in multiple states till that point. So glad I experienced 'clean' cannabis, and starting with clean water turns out to be very important.
Substitute
Member
No, it's me you had the conversation with. I was signed in to a different account I created by accident. CDMHog.
Douglas.Curtis
Autistic Diplomat in Training
So you're on repeat?
