regal8r, it sounds like you have too much air for your reservoir size. The 5g bucket should be just fine, the goal is to have the swing take place over 7-10 days at the start of flower.
Can you do an experiment?
- Check the pH of the res
- Turn off the light and turn off the airpump for 15 minutes
- Check the pH again
Is the pH higher or lower? If the pH has dropped, you have too much air going through your 4'ish gallons of solution.
I do know a few growers who start with a mild strength solution, pH'd to 6.0'ish. They do not top off daily, and the evaporation due to aeration over time causes the solution to concentrate over time. The pH is at around 5.4-3 when they eventually re-fill with whatever nute solution they top off with. I thought it was a lot of stress on the roots, being dried out for so long between re-fills. I knew both growers only briefly.
Englishrick, good point! I've never even thought of that being a 'feature' of nutrients.
In either case, reversing the process is indeed the solution as Hydro8 explained. At some point in the swing, they both allow cannabis free absorption of each element. .
Your plant looks normal and good.
My next trouble shooting thought would be to get a second ph pen. I have had PH pens work fine in a certain range then drop off the map in a different range. Paper PH strips are a cheap 2nd test also.
With RDWC, if I go with let's say 20 total gallons for 1 plant in a 2x2 SCROG, how long could I go without having to do a water change? Right now I'm changing solution every Friday, but with increased res volume I think I could get away with at least twice a month. Does that sound right? Thanks for your help.
Sorry, I did not realize the size plant you have in your 5 gallon bucket. You seriously do need a larger reservoir to slow your pH changes. A 15 gallon res, with about 10-12 gallons of water would be about right. Your goal should be around 7-10 days for a full pH swing at the beginning of flower. This shortens as demands increase in flower, and will stay within safe ranges.I realize now that there is just too little solution volume to effectively buffer pH changes with a plant of this size and how much it's drinking. We're drinking a gallon per day now with my 2x2 SCROG completely filled AND dense foliage under the canopy but above the SCROG. I will probably end up getting a water pump and aux reservoirs and switching to RDWC since I will also have to leave town for about 5 days in a few months and I have no one to take care of the plants.
A reservoir makes things so much easier to manage and keep consistent.
One thing that will be important to maintain for 5 days is the volume level. When plant is small, 5 days with a 20 gal res the level change would be minimal, when a plant is big it can drain a gallon or so a day.
However much the level drops in your res is how much it will drop from net pot. You could test it by getting a tote/reservoir and taking 5 gallons out and see how far the level drops.
I had a 15 gal reservoir on two 5-gal buckets/plants I would leave it for 2-4 days in flower no issues the level would be down 3 inches or so, the plants seems unfazed. More then 3 inches down would make me feel uncomfortable.
One of my next experiments is an auto feed for a reservoir, a raised container with a tube that will gravity feed into the reservoir when the level gets below it. If it works it would keep the level constant and I could leave for a week or so.
I like to change my nutes at least every 10-14 days closer to 7 in flower. Some guys will run the same nuts for 30 days or more. 7-10 days just seems like it keeps everything clean, fresher and the plants seem happy.
Agreed on all accounts. I have a couple 18gal totes I'm gonna move to. Thanks!Sorry, I did not realize the size plant you have in your 5 gallon bucket. You seriously do need a larger reservoir to slow your pH changes. A 15 gallon res, with about 10-12 gallons of water would be about right. Your goal should be around 7-10 days for a full pH swing at the beginning of flower. This shortens as demands increase in flower, and will stay within safe ranges.
Personally, I don't recommend RDWC. At the end of flower, my DWC reservoirs are still clean. I use zero chlorine, h202, enzymes or other products to keep it clean. The DWC setup is a simple tub, with airlines and airstones. All of the additional cracks and crevices from plumbing in RDWC makes this nearly impossible. In addition, RDWC costs more to build and run than DWC and the outputs are the same.
Sorry, I did not realize the size plant you have in your 5 gallon bucket. You seriously do need a larger reservoir to slow your pH changes. A 15 gallon res, with about 10-12 gallons of water would be about right. Your goal should be around 7-10 days for a full pH swing at the beginning of flower. This shortens as demands increase in flower, and will stay within safe ranges.
Personally, I don't recommend RDWC. At the end of flower, my DWC reservoirs are still clean. I use zero chlorine, h202, enzymes or other products to keep it clean. The DWC setup is a simple tub, with airlines and airstones. All of the additional cracks and crevices from plumbing in RDWC makes this nearly impossible. In addition, RDWC costs more to build and run than DWC and the outputs are the same.
[/FONT]Canna said:[FONT=Arial, Helvetica, sans-serif]Influencing pH
Plants are capable of actively influencing the nutrient solution’s pH. If the intake of food is disturbed when the plants suffer a pathogenic attack, for example mould, it can cause the nutrient solution’s pH to drop below 3. Another symptom can be noticed with iron deficiencies and, in this case, the pH is actively lowered to make iron more available to the plants. For this reason, it is not advisable to have the same value for the pH continuously. With a good nutrient solution and a pH between 5.2 and 6.2 there should be no nutrient problems. If the pH should be lower than 5.0 or higher than 6.4 for a few days, it is advisable to carry out manual adjustments or to change the composition of the nutrient.
Hoping you guys can help me. I currently have Pineapple Chunk going in a 5gal DWC, day 8 of flower and using only Mega Crop 1 part at 2.2ish EC and change solution every week religiously. Every day this week, I come home to check on my girl and find the res has a pH of <4. I'm having to add 1mL/gallon to get it back up to 5.6 pH. 24hrs later, it's back down to <4pH without fail. I use an Apera PH60 probe that I calibrate once a week and have no signs of root rot (normal smell and no sliminess) but just some staining. Here are some pics. TIA.
https://imgur.com/a/7hEBtTe
Forgot to mention I'm also using RO water.
Very interesting. I would much rather add something the plant will be using, than some random tap/well water elements. This is the first time I've heard of using p/k this way. It makes a LOT of sense. And to think, I've had a jar of it around for years until about a year ago. lol Never used it much so I dumped it for the jar.Root secretions are definitely effective in moving ph,, canna aqua actual website says that if you see a pH drop it's an indicator to add pk 13/14,, i have used this pH drop indicator for years with fantastic success,, i add only enough pk to bring the pH back and I don't even check how many millilitres it takes as I just mix the tank and check the pH,,
Pathogens should really have been killed in cloning and surface sterilisation,, but it's not like I'm in the swing of doing this myself yet
If I ever need to solve any problems I just flush with water,, loads and loads of water,,, then I remix a tank (canna aqua) and run it,, then I check it progressively,, if pH drop is heavy il add pH and watch it rise,, that is actually my usual time and event when I'm forced to add pk/1314
Root secretions are definitely effective in moving ph,, canna aqua actual website says that if you see a pH drop it's an indicator to add pk 13/14,, i have used this pH drop indicator for years with fantastic success,, i add only enough pk to bring the pH back and I don't even check how many millilitres it takes as I just mix the tank and check the pH,,