Is CalMag a pH buffer?

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OrlandoSmooth

OrlandoSmooth

7
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Hello Everyone,

I’ve been having major pH down swings recently. I run a DWC with tap water and the GH 3 part series. My plants are currently in late veg but for the past month have been having major problems with my pH dropping quickly. I haven’t really had this problem before and have about 4 grows under my belt. At first, I assumed I was overfeeding so I cut my nutes from 3/5 to 2/5 and still have been seeing problems with pH drop (as well as other deficiencies now). After doing some minor research and remembering my days using RO water, I added some CalMag to a new solution at 3/5 and haven’t seen any downward pH swings yet. Does CalMag act as some sort of buffer? Can anyone please explain this to me or educate me on why i’m experiencing this problem? Thank you!!
 
phxazcraig

phxazcraig

519
93
I don't know and am interested in the answers, but it would likely be a good idea for you to list all your nutrients.
 
Pushrod Monkey

Pushrod Monkey

1,174
163
Magnesium nitrate is neutral pH but calcium carbonate can range from 6 to 10. So it can definitely alter your pH.
 
OrlandoSmooth

OrlandoSmooth

7
3
Hello Everyone,

I’ve been having major pH down swings recently. I run a DWC with tap water and the GH 3 part series. My plants are currently in late veg but for the past month have been having major problems with my pH dropping quickly. I haven’t really had this problem before and have about 4 grows under my belt. At first, I assumed I was overfeeding so I cut my nutes from 3/5 to 2/5 and still have been seeing problems with pH drop (as well as other deficiencies now). After doing some minor research and remembering my days using RO water, I added some CalMag to a new solution at 3/5 and haven’t seen any downward pH swings yet. Does CalMag act as some sort of buffer? Can anyone please explain this to me or educate me on why i’m experiencing this problem? Thank you!!
just to expand: i run dwc with general hydroponics 3 part series. Nothing extra. i run it with hard tap water. right now i follow the schedule for aggressive veg growth but mix it at 3/5 (without calmag). anything more in the past has given me fast downward pH swings (6.0/6.2 to 5.0- in 48hrs).

Now, after adding Botanicare CalMag at full strength 5ml/gal. It seems that my pH is holding stable around 6.

I just ultimately would like to wrap my head about what causes these upward and downward swings in pH. I know there are natural swings caused by reactions when the plants feed, but there is no way the swing can be as finicky as i’m experiencing.

Long story short, what, if anything, will increase the pH buffer capacity of my solution?

Thanks yall.
 
OrlandoSmooth

OrlandoSmooth

7
3
It'd depend on source of calcium in your CalMag supplement. If it's calcium carbonate yes, if nitrate no.. That said, I use my tap water (calcium carbonate) to buffer my feed.
I used Botanicare CalMag. Im almost positive it’s calcium nitrate.

I can’t think of any reasons why i’m having these swings. I run extremely clean systems and moved to tap water for the reasons you stated about buffering… Do you have any more guesses?
 
jguit

jguit

Supporter
906
143
I used Botanicare CalMag. Im almost positive it’s calcium nitrate.

I can’t think of any reasons why i’m having these swings. I run extremely clean systems and moved to tap water for the reasons you stated about buffering… Do you have any more guesses?
Do you have a report on your tap water? It might not have enough alkalinity to keep your pH stable.
 
OrlandoSmooth

OrlandoSmooth

7
3
Do you have a report on your tap water? It might not have enough alkalinity to keep your pH stable.
Yes. I just pulled it. It says the alkalinity is 74-205ppm. That’s a big difference. Do you think it’s possible that I used water out of my tap that had a higher alkalinity during my previous grows and maybe i’m getting water with lower alkalinity now? If it does have low alkalinity, what could I add to help?
 
jguit

jguit

Supporter
906
143
I'd get other opinions as I'm able to use my tap water and have no personal experience with it but maybe look into something like potassium silicate?
 
Anthem

Anthem

3,353
263
Yes. I just pulled it. It says the alkalinity is 74-205ppm. That’s a big difference. Do you think it’s possible that I used water out of my tap that had a higher alkalinity during my previous grows and maybe i’m getting water with lower alkalinity now? If it does have low alkalinity, what could I add to help?
I have not seen many municipals water quality reports. But rather than alkalinity. Does your report have PPMs of say magnesium and Calcium. I have those numbers in my water quality report. PH going down is typically plants being underfeed in hydro but those bucket deals are not like a regular DWC or Hydro Set up
 
smokedareefer

smokedareefer

1,574
263
Hello Everyone,

I’ve been having major pH down swings recently. I run a DWC with tap water and the GH 3 part series. My plants are currently in late veg but for the past month have been having major problems with my pH dropping quickly. I haven’t really had this problem before and have about 4 grows under my belt. At first, I assumed I was overfeeding so I cut my nutes from 3/5 to 2/5 and still have been seeing problems with pH drop (as well as other deficiencies now). After doing some minor research and remembering my days using RO water, I added some CalMag to a new solution at 3/5 and haven’t seen any downward pH swings yet. Does CalMag act as some sort of buffer? Can anyone please explain this to me or educate me on why i’m experiencing this problem? Thank you!!
Pictures of the whole plant and roots?
 
C

Ccale

2
1
If your looking for a source of calcium to act as a buffer try the neutral formula get food grade calcium sulfate its low water soluble and neutral oh value it slowly releases the cal and sulfate causing it to act as a none chlorine buffer or acts like citrate acid aka buffer Calnitrate is ph down calcarbonater or bicarb is a ph up and calcloride has chlorine in it for the ph WARNING when using calsulfate as after all other nutrients and when doing an ec test on your pin 10 ppr will be enough calcium and sulfate for most of your plants complete grow so suggest you do your weekly or biweekly nutrient change and not meant to be used in a drip or spray hydro system ull get clogs and one last thing do not use dry wall mix for your calsulfate
 
C

Ccale

2
1
If your looking for a source of calcium to act as a buffer try the neutral formula get food grade calcium sulfate its low water soluble and neutral PH value it slowly releases the cal and sulfate causing it to act as a none chlorine buffer or acts like citrate acid aka buffer Calnitrate is ph down calcarbonater or bicarb 8.5ph CALACETATE 10ph up and calchloride calhydroxide has chlorine in it for the ph WARNING when using calsulfate aDD after all other nutrients and when doing an ec test on your pPM 10 ppM will be enough calcium and sulfate for most of your plants complete grow so suggest you do your weekly or biweekly nutrient change and not meant to be used in a drip or spray hydro system ull get clogs and one last thing do not use dry wall mix for your calsulfate... U can get calcium in all PH balance adjustment needs
And since the topic is calmag I should mention if you need caLMag and use the calsulfate in the above get a bag of Epsom salt at dg and get the plan Jane none fragrant peppermint what ever they got added to the magnesium sulfate.. PH ballancing. P and K use nitrates usually so that gives you some of your N use your sulfates which should be a neutral or Close to remaining N would be your ammonium and and if u need a ph up baking soda a sodium bicarbonate of you got oh problems it's cause of nutrient types nitrate down sulfate neutral usually carbonate 8.5ph and acetate close to 10ph up hydroxide chloride I think are your chlorine stability effects and citrate acid is buffer which is how long u get PH stability most effective with chloride nutrient or tap water chlorine think I got all that correct it's close thinking its potassium sulfate that's the none neutral PH sulfate or potash sulfate not sure on witch one it is cause potash has potassium and they can be sulfate and chloride depending on what's being used is what u get there on the premix stuff
 
Last edited:
phxazcraig

phxazcraig

519
93
If your looking for a source of calcium to act as a buffer try the neutral formula get food grade calcium sulfate its low water soluble and neutral oh value it slowly releases the cal and sulfate causing it to act as a none chlorine buffer or acts like citrate acid aka buffer Calnitrate is ph down calcarbonater or bicarb is a ph up and calcloride has chlorine in it for the ph WARNING when using calsulfate as after all other nutrients and when doing an ec test on your pin 10 ppr will be enough calcium and sulfate for most of your plants complete grow so suggest you do your weekly or biweekly nutrient change and not meant to be used in a drip or spray hydro system ull get clogs and one last thing do not use dry wall mix for your calsulfate
I'm sure this is technically correct, but please learn to use sentences with periods. The above is a single sentence. Try reading it out loud. You might see why some of us find it hard to follow.
 
phxazcraig

phxazcraig

519
93
I used Botanicare CalMag. Im almost positive it’s calcium nitrate.

I can’t think of any reasons why i’m having these swings. I run extremely clean systems and moved to tap water for the reasons you stated about buffering… Do you have any more guesses?
I use a Botanicare product called Silica Blast. Its label says it is Potassium Silicate.

My experience - I too have had some pH swings (in my reservoir) and am trying to figure out why. Mine are not so dramatic - but they have gone in both directions. It's usually like this:
-mix nutes in RO water, pH ends up at about 6.1. Sometimes even 6.0. My goal has been 6.0, so I usually have to add a small bit of pH Down.

After a day in the 14 gallon reservoir - drain to waste, and refilled with about 12 gallons of new nutes every 2 days - my pH might drift down to 5.9 or even 5.8. I have a Bluelab pH controller set up pumping pH Down and set at 6.0. Usually it is very stable, but occasionally it drops below the setting by itself. I add a teaspoon of pH Up and it usually corrects in 20-30 minutes. So mine is pretty stable, but still changes without any new inputs.

Here's my regimen in case it helps:
1. Silica Blast - 2.5ml/gal, then wait 1 hour for it to completely dilute in the water. I've seen various recommendations on waiting or not waiting, and an hour wait is the longest I've heard of. I do it just in case and it's worked so far as I know.
2. Calimagic - per the GH Flora chart that I'm using. Currently 1.9 ml/gal in flower, but used to be higher. This is necessary because I'm growing in coco and using RO water. My tap water is higher in EC than 2.5ml/gal, by the way.

- a note: in various sites, including the General Hydroponics site, I see strong warnings that Silica Blast needs to be mixed first, then Calimagic. If no silica, then start with Calimagic. Just passing it on.

3. GH nute trio in proportions based on their charts and the age of the plant. (Micro, Gro and Bloom)
4. Once flowering, I started adding Floralicious and Liquid Koolbloom in chart proportions.

At this stage I have 95% of the EC in place and I like it around 1200-1500 max. I end up diluting my mix a bit usually, as I get tip burn above 1200 on my current grow.

5. Now I add in the final supplements - Diamond Nectar Humic acid at 2.5ml/gal. A sprinkling of Yucca powder as a wetting agent. And finally 2.5ml/gal of 33% food-grade H2O2 to control algae and stuff in the tank. I've got 2nd thoughts on this, because while it seems to be working fine, I assume it also kills any beneficial mychorrizae at work in the root systems.

At the end of this, my pH is either 6.0 or 6.1. Sometimes I'll see my Bluelab controller crying 'Help! Ineffective Control' or some such warning. That means it's gone an hour or so trying to get the pH down to 6.0 and not succeeding. Invariably that seems related to me putting too much pH Up in from not waiting 10-20 minutes for it to mix thoroughly in my reservoir. Normally the pH drifts down, if anything, after 24 hours. It doesn't happen enough that I wish i had the 2-way controller. (Controls both up and down with inputs for both.)
 
Cashmeh

Cashmeh

1,632
163
No calmag provides almost 0 alkalinity. Here is a quote from Aquaman

"Potassium silicate is used for silicate and ph stabilization. Silicon dioxide is close to PH neutral and is the form available to plants. If I remember right but I'm fairly sure.

So if using for PH stabilization (alkalinity) potassium silicate is a great option. If just for silica then silicon dioxide is a better choice."

There are ways to test alkalinity in your water. I use fish tank strips. Alkalinity is what prevents ph swings and without it, you will always fluctuate.

I too use silica blast but will be ditching it for raw potassium silicate since it will add more alkalinity.

Tap water has dissolved metals and other elements that provide alkalinity. If your using ro you can mix it with your tap water at 50/50 for alkalinity also.
 
Smokey0418

Smokey0418

161
43
Ph downswings of .5 or a bit more in very short periods of time. Sure sign of root issues , could be as simple as a pot inoculation to resolve.
 
JohnnyApp

JohnnyApp

62
33
You only need 12 elements to grow cannabis hydroponically, humic acid and bennies are not required in a sterile hydroponic environment, and silica products are no longer recommended for liquid feeds due to the likelihood of salt precipitation. Your water should be dead, the opposite of organic. Humic acid is an organic material. Also avoid their sweetners which contain 5% molasses and or 95% cane sugar, also organic materials. Plants are autotrophic and produce sugar, they don’t need to be fed it in hydro. Sugar used is to feed microbes in soil.

A chiller is required to keep proper res temp.and prevent bacteria growth, products like hydro guard are only required in an improper setup.

cleanse or uc roots, cococal, or calimagic, and a/b. All you need to veg.

for flower simply swap veg a/b for bloom and add a mkp supplement. Nothing to it. And it’s definitely best to only use ro in hydro.
 
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