I changed my res water today. Hadn't done it in three weeks.
What's the science behind the philosophy of changing water every 7 days like so many posts I read on forums suggest?
If I monitor pH, PPM and temps 24/7, and make sure all values are within acceptable parameters, what's chemically different in "fresh" water versus 3 weeks old water? My res is sealed, cooled and protected from light. I've read "nutrients get weaker over time." Wtf does that even mean? Why would they get weaker over time in the res and not in the bottle? N and P are N and P. They're not organic, they're not alive. If P is in the res, P is in the res and it'll stay there until the plant eats it up for lunch.
Am I missing something?
Re: [GFP] Double SS400W Grow Journal
by FCGFrank » Wed Feb 20, 2013 7:38 pm
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Re: [GFP] Double SS400W Grow Journal
by SisterMaryElephant » Thu Feb 21, 2013 12:23 am
NPK are the main nutrients but there are many other micro-nutrients too. If you keep the PPM/EC corrected, adjusted for the current growth phase and levels topped off with good water there isn't much difference but you can build up levels of nutrients that are needed less and not enough of something needed while still maintaining a desired PPM that the TDS meter cannot differentiate. I know growers that only do a complete drain and change twice. Once when they switch to flower and once before veg. Monthly, weekly, daily can depend on other factors (like res size and health) too.
TDS meters just say how much Total Dissolved Solids (TDS) you have. It doesn't say how much of each NPK. etc just how much of everything.
TDS meters just say how much Total Dissolved Solids (TDS) you have. It doesn't say how much of each NPK. etc just how much of everything.
Disclaimer:
I still use HID and I'm NOT an LED expert. All of my LED knowledge is from other parties or research so I can't say from first hand experience one way or another. I also run a medical grow consulting business in SoCal.
I still use HID and I'm NOT an LED expert. All of my LED knowledge is from other parties or research so I can't say from first hand experience one way or another. I also run a medical grow consulting business in SoCal.
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Re: [GFP] Double SS400W Grow Journal
by FCGFrank » Thu Feb 21, 2013 4:20 pm
SisterMaryElephant wrote: I know growers that only do a complete drain and change twice. Once when they switch to flower and once before veg. Monthly, weekly, daily can depend on other factors (like res size and health) too.
Good to know because this is what I would do next on my next grow. If using organic stuff like mycos, you have more to gain by keeping that water, which is like an aquarium ecosystem in the end, rather than changing it out every week.
I see what you mean about macro and micronutrients imbalance, though. I imagine nutes are designed to account for this possibility and that as long as all the prerequesites basic parameters are in check, such an occurrence shouldn't occur.
On the other hand growth has slowed down dramatically, (used to be 1.2inch a day last week, 0.3inch/day in the past 3 days). pH is all out of whack, but the plants arent showing signs of damage or deficiency.
The organic crap has gummed up my res a lot. I think I'll have to change it out (or clean it thorough).
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Re: [GFP] Double SS400W Grow Journal
by SisterMaryElephant » Thu Feb 21, 2013 4:41 pm
If you want to try to change the res less frequently, you might trying building up to the 2 + month change outs. Try every month and then build up to 2 months. You might need a bigger external res to get that much time too, if your plants use what's in your res quickly, it's not much more work to flush with clean water for a minute or two and start over. If you're having balance issues at 3 weeks then 4-8 weeks might be too much for your current system. Try it and see... 
Disclaimer:
I still use HID and I'm NOT an LED expert. All of my LED knowledge is from other parties or research so I can't say from first hand experience one way or another. I also run a medical grow consulting business in SoCal.
I still use HID and I'm NOT an LED expert. All of my LED knowledge is from other parties or research so I can't say from first hand experience one way or another. I also run a medical grow consulting business in SoCal.
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Re: [GFP] Double SS400W Grow Journal
by FCGFrank » Thu Feb 21, 2013 7:41 pm
SisterMaryElephant wrote:If you want to try to change the res less frequently, you might trying building up to the 2 + month change outs. Try every month and then build up to 2 months. You might need a bigger external res to get that much time too, if your plants use what's in your res quickly, it's not much more work to flush with clean water for a minute or two and start over. If you're having balance issues at 3 weeks then 4-8 weeks might be too much for your current system. Try it and see...
I was responsible for the balance issue -- I didn't premix my myco powder and used way too much of it.
I'll avoid it next time
I guess it makes sense to change it more frequently in bloom since larger plants will drink and consume more nutes, but in 45 days of vegging, the plants have eaten or drank very little.- FCGFrank
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Re: [GFP] Double SS400W Grow Journal
by SisterMaryElephant » Thu Feb 21, 2013 10:22 pm
Absolutely, keep an eye on health and see what they do.
Disclaimer:
I still use HID and I'm NOT an LED expert. All of my LED knowledge is from other parties or research so I can't say from first hand experience one way or another. I also run a medical grow consulting business in SoCal.
I still use HID and I'm NOT an LED expert. All of my LED knowledge is from other parties or research so I can't say from first hand experience one way or another. I also run a medical grow consulting business in SoCal.
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Re: [GFP] Double SS400W Grow Journal
by FCGFrank » Fri Feb 22, 2013 10:31 am
I woke up this morning to find pH at 8.3. I had no ph Down left yesterday (my mistake) so couldn`t re-adjust pH.
I bought some. I inspected plants under white light, a few leaves are showing signs of a defficiency, no doubt because they were locked out of nutrients at that pH.
Now, do I adjust it back in 0.5 increments back down to 5.8, every 4 hours, or in one go?
Also, this pH down I bought has an effect on PPM. My ph Down raises PPM by like 400. Wtf is going on? I can't link to it I guess but it says 17% Phosphoric Acid.
I bought some. I inspected plants under white light, a few leaves are showing signs of a defficiency, no doubt because they were locked out of nutrients at that pH.
Now, do I adjust it back in 0.5 increments back down to 5.8, every 4 hours, or in one go?
Also, this pH down I bought has an effect on PPM. My ph Down raises PPM by like 400. Wtf is going on? I can't link to it I guess but it says 17% Phosphoric Acid.
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Re: [GFP] Double SS400W Grow Journal
by SisterMaryElephant » Fri Feb 22, 2013 12:24 pm
I'd try to get it close to the desired PH in one shot and then fine tune after. Don't go too far then yo-yo with up and down though.
Just get the PH right, first, then see how they respond. If they show signs of nutrient burn dilute a little with PH adjusted water. What, in your system, is causing the PH to jump so high? Is your water that bad? What is your method, step by step, for preparing nutrients?
Just get the PH right, first, then see how they respond. If they show signs of nutrient burn dilute a little with PH adjusted water. What, in your system, is causing the PH to jump so high? Is your water that bad? What is your method, step by step, for preparing nutrients?
Disclaimer:
I still use HID and I'm NOT an LED expert. All of my LED knowledge is from other parties or research so I can't say from first hand experience one way or another. I also run a medical grow consulting business in SoCal.
I still use HID and I'm NOT an LED expert. All of my LED knowledge is from other parties or research so I can't say from first hand experience one way or another. I also run a medical grow consulting business in SoCal.
- SisterMaryElephant
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Re: [GFP] Double SS400W Grow Journal
by FCGFrank » Fri Feb 22, 2013 12:41 pm
The issue came from the damn myco powder I added 2 weeks ago. I followed the instructions but it was way too much, and I didn't pre-mix it in a water jug before adding it to the res, so not only did it not dissolve properly, but some of it fell to the bottom of the res and formed lumps under some of the air discs or the cooling coil. When I changed the res a few days ago, all that lumped myco powder was mixed up again and it started to make a thick foam at the top of the res.
This morning I took the plants out, transferred the water into another res temporarily, and completely cleaned the shit out of the res. Removed all the gum, residue, etc. I added about 8 gal of fresh RO water, I transferred back 12 gal of the old water, added 1/4 strenght nute, adjusted pH, and pH hasn't budged ever since the cleaning.
When I add nutes to the res I take a 1 gallon jug, fill it to half capacity with RO water, I add my nutes to it, shake, adjust pH then dump it into the res slowly as I watch the PPM meter, making sure I don't overdo it.
This was user error due to a first time use of an unknown product that came with vague/incomplete instructions to boot. Tbh, ALL Advanced Nutrients recommendations are completely bull. Their dosing suggestions make no sense whatsoever.
This morning I took the plants out, transferred the water into another res temporarily, and completely cleaned the shit out of the res. Removed all the gum, residue, etc. I added about 8 gal of fresh RO water, I transferred back 12 gal of the old water, added 1/4 strenght nute, adjusted pH, and pH hasn't budged ever since the cleaning.
When I add nutes to the res I take a 1 gallon jug, fill it to half capacity with RO water, I add my nutes to it, shake, adjust pH then dump it into the res slowly as I watch the PPM meter, making sure I don't overdo it.
This was user error due to a first time use of an unknown product that came with vague/incomplete instructions to boot. Tbh, ALL Advanced Nutrients recommendations are completely bull. Their dosing suggestions make no sense whatsoever.
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Re: [GFP] Double SS400W Grow Journal
by SisterMaryElephant » Fri Feb 22, 2013 2:47 pm
You fill your res 1/2 gallon at a time? I like to fill the res with RO, pre-adjust the PH to 6-ish first, then check PPM, add nutes etc at the correct strength and then finalize PH after everything gets mixed up well. Check again after an hour or so.
When topping off levels, I add PH corrected water and then add nutrients to get the PPM back up and then recheck after an hour for minor corrections.
A lot of the hydroponic PH Down uses phosphoric acid so I wouldn't worry about that unless you see signs of toxicity. AN nutrients are pretty popular but I have no idea what their PPM schedule is like; you can find other growers' AN schedules online with a quick search. Different genetics and growing styles may have different requirements which is why keeping a log is a good idea until you get everything figured out.
When topping off levels, I add PH corrected water and then add nutrients to get the PPM back up and then recheck after an hour for minor corrections.
A lot of the hydroponic PH Down uses phosphoric acid so I wouldn't worry about that unless you see signs of toxicity. AN nutrients are pretty popular but I have no idea what their PPM schedule is like; you can find other growers' AN schedules online with a quick search. Different genetics and growing styles may have different requirements which is why keeping a log is a good idea until you get everything figured out.
Disclaimer:
I still use HID and I'm NOT an LED expert. All of my LED knowledge is from other parties or research so I can't say from first hand experience one way or another. I also run a medical grow consulting business in SoCal.
I still use HID and I'm NOT an LED expert. All of my LED knowledge is from other parties or research so I can't say from first hand experience one way or another. I also run a medical grow consulting business in SoCal.
- SisterMaryElephant
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- Joined: Thu Sep 22, 2011 10:05 pm
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