U
Ultra Current
pH is very important when you are growing cannabis. Growing cannabis in soil and growing plants hydroponically require totally different pH’s so don’t be confused by this. I will only talk about hydro here. You want to stay in a range of 5.8 – 6.2 at all times. Falling below or above this mark can cause (not will cause) serious problems. If your solution is not pH’d to the correct numbers, then the plants will not be able to receive and use the nutrients that you are supplying to them.
I have a lot of experience with many company's pH and TDS / PPM meters. When you buy one of these devices from a grow shop it usually means that you did not buy an expensive lab grade model and the result is that your device is made with cheaper components. I understand that most growers don't have thousands of dollars to buy a lab grade meter and this is ok but there are some things that you must know. With my testing with Hanna, Nutradip and Blue Lab I see similar problems in them that can give you a false reading.
Just because you might have a top of the line pH meter (pH meter is a necessity in hydroponics) doesn’t mean that the reading that it is giving you is correct. There are a few factors that will give you a false reading. Here is a list:
1. Your calibration solution is comtaminated, old or was stored in high temperatures or exposed to light for too long.
2. There is a build up of gunk on the pH probe. Solution: Gently clean the probe with a soft brush and recalibrate.
3. pH probe is broken or it’s beyond it’s life span. Buying pH meters at grow shops is an ecconomcal way of aquiring a meter but it is not lab grade and cheaper components are used in the process. pH probes can damage very easily and are also sensitive. When the pH probe is not being used, it is very important to keep it in 7.0 calibration solution. When you open the box for the first time from buying the meter, there is not always solution attached to the bottom of the probe but it is dipped in some sort of salt so don’t be confused by this and think that you can store your probe without solution. Your probe will eventually dry up and brake if you were to dry it out. It is very simple to know if you have a damaged probe. This process will require 2 different calibration solutions (pH 4, pH 7 or pH 10). Most meters that I’ve seen in the US use pH 4 and pH 7. Your owners manual will tell you if you have to use the 7 or the 4 first. It is important to listen to what the company of the specific meter that you have tells you. If your meter does not contain a computerized calibration method then you will see that you calibrate it with a screw driver or there are knobs that you turn or you may have to digitally punch in numbers to a screen on your device. If your meter calibrates to a screw driver or some sort of knob that you turn then it is important for you to know that when you pH the 4 first and finish, you then clean the probe and insert it into the pH 7 calibration solution. If you insert the probe into the 7 and it doesn’t read pH 6.8, 6.9, 7.0 or 7.1, 7.2 (normally I wouldn’t insert the 6.8 or 7.2 in here but the meters at grow shops are not lab grade and have a greater margin of error), then your probe has gunk on it or is broken and needs to be replaced. You can try to recalibrate it but it will not work because it will move the pH 4 somewhere else and you’ll keep going back and forth just waisting time. You will usually have to do some tweaking going back and forth between the pH 4 and 7 solution because there is a lot of little spaces between 4.0 - 4.1 and 3.9 - 4.0 as well as 6.9 – 7.0 and 7.0 – 7.1. Once you get the meter to read 4.0 and 7.0, then your meter will be accurate for at least that usage but you should calibrate your meter once a week to be safe. Your meter is a computer and you can’t just trust the numbers that it is spiting out at you. Always question the reading that you are getting and compare it to what your plants are telling you. The first signs that you will usually see first, if your probe goes out of alignment, is yellowing of the edges of fan leaves (Magnesium Lockout) or brown / black spots on leaves (Calcium Lockout). If you have the solution up to the required PPM and you see these signs on the leaves, then that should be a big read flag and will require you to calibrate your probe or check if it is broken and get a working one. You will notice within a period of time, the pH of your solution will fluctuate. Depending on what different things that you add to your Rez can make the fluctuation different so if your solution normally rises and then you add something else to the mix and then it does the opposite then it’s good to keep this in mind. If you know that your solution rises, then set your solution to 5.8 and let it climb to 6.2 and then pH it down, if your solution falls, then set it to 6.2 and let it fall down to 5.8 and pH it back up. This fluctuation should not peak within a 24 hour period with most nutrients so if you see this happen you most likely have root problems (root rot / pythium) or some sort of pathogen, fungus or algae. We will cover this in another chapter.
4. RF interference from your digital/electronic ballast. RF interference has a major affect on many pH / TDS / PPM meters that are sold at grow shops. It is important that your ballasts and any equipment that gives off RF is turned off before calibrating and using your meter. I have spent countless hours on the phone with the owners of these company's complaining about how the RF interference from my ballasts are affecting my reading and they would send me brand new meters that would have the exact same problem. Make sure all your equipment is turned off when using your meters.
I hope that you guys find this information useful. Happy Growing!
The information in this post has a copyright and is from a chapter in the book that I've been writing on hydroponics.
I have a lot of experience with many company's pH and TDS / PPM meters. When you buy one of these devices from a grow shop it usually means that you did not buy an expensive lab grade model and the result is that your device is made with cheaper components. I understand that most growers don't have thousands of dollars to buy a lab grade meter and this is ok but there are some things that you must know. With my testing with Hanna, Nutradip and Blue Lab I see similar problems in them that can give you a false reading.
Just because you might have a top of the line pH meter (pH meter is a necessity in hydroponics) doesn’t mean that the reading that it is giving you is correct. There are a few factors that will give you a false reading. Here is a list:
1. Your calibration solution is comtaminated, old or was stored in high temperatures or exposed to light for too long.
2. There is a build up of gunk on the pH probe. Solution: Gently clean the probe with a soft brush and recalibrate.
3. pH probe is broken or it’s beyond it’s life span. Buying pH meters at grow shops is an ecconomcal way of aquiring a meter but it is not lab grade and cheaper components are used in the process. pH probes can damage very easily and are also sensitive. When the pH probe is not being used, it is very important to keep it in 7.0 calibration solution. When you open the box for the first time from buying the meter, there is not always solution attached to the bottom of the probe but it is dipped in some sort of salt so don’t be confused by this and think that you can store your probe without solution. Your probe will eventually dry up and brake if you were to dry it out. It is very simple to know if you have a damaged probe. This process will require 2 different calibration solutions (pH 4, pH 7 or pH 10). Most meters that I’ve seen in the US use pH 4 and pH 7. Your owners manual will tell you if you have to use the 7 or the 4 first. It is important to listen to what the company of the specific meter that you have tells you. If your meter does not contain a computerized calibration method then you will see that you calibrate it with a screw driver or there are knobs that you turn or you may have to digitally punch in numbers to a screen on your device. If your meter calibrates to a screw driver or some sort of knob that you turn then it is important for you to know that when you pH the 4 first and finish, you then clean the probe and insert it into the pH 7 calibration solution. If you insert the probe into the 7 and it doesn’t read pH 6.8, 6.9, 7.0 or 7.1, 7.2 (normally I wouldn’t insert the 6.8 or 7.2 in here but the meters at grow shops are not lab grade and have a greater margin of error), then your probe has gunk on it or is broken and needs to be replaced. You can try to recalibrate it but it will not work because it will move the pH 4 somewhere else and you’ll keep going back and forth just waisting time. You will usually have to do some tweaking going back and forth between the pH 4 and 7 solution because there is a lot of little spaces between 4.0 - 4.1 and 3.9 - 4.0 as well as 6.9 – 7.0 and 7.0 – 7.1. Once you get the meter to read 4.0 and 7.0, then your meter will be accurate for at least that usage but you should calibrate your meter once a week to be safe. Your meter is a computer and you can’t just trust the numbers that it is spiting out at you. Always question the reading that you are getting and compare it to what your plants are telling you. The first signs that you will usually see first, if your probe goes out of alignment, is yellowing of the edges of fan leaves (Magnesium Lockout) or brown / black spots on leaves (Calcium Lockout). If you have the solution up to the required PPM and you see these signs on the leaves, then that should be a big read flag and will require you to calibrate your probe or check if it is broken and get a working one. You will notice within a period of time, the pH of your solution will fluctuate. Depending on what different things that you add to your Rez can make the fluctuation different so if your solution normally rises and then you add something else to the mix and then it does the opposite then it’s good to keep this in mind. If you know that your solution rises, then set your solution to 5.8 and let it climb to 6.2 and then pH it down, if your solution falls, then set it to 6.2 and let it fall down to 5.8 and pH it back up. This fluctuation should not peak within a 24 hour period with most nutrients so if you see this happen you most likely have root problems (root rot / pythium) or some sort of pathogen, fungus or algae. We will cover this in another chapter.
4. RF interference from your digital/electronic ballast. RF interference has a major affect on many pH / TDS / PPM meters that are sold at grow shops. It is important that your ballasts and any equipment that gives off RF is turned off before calibrating and using your meter. I have spent countless hours on the phone with the owners of these company's complaining about how the RF interference from my ballasts are affecting my reading and they would send me brand new meters that would have the exact same problem. Make sure all your equipment is turned off when using your meters.
I hope that you guys find this information useful. Happy Growing!
The information in this post has a copyright and is from a chapter in the book that I've been writing on hydroponics.
