[Ymir]

I emailed JRPeters and since my PH was so high (7.8 out of the tap) they recommend I use sulfuric acid (battery acid from the auto parts store). I've read about this in the past but never got around to trying it. It's a lot more stable than other ph down solutions and a lot cheaper, lasts longer and doesn't throw the NPK out of whack since it's just sulfur which most nutes don't have a lot of anyway.

$5 at the auto parts store = gallons of PH Down solution.

Instructions: (Make sure what you buy has instructions for filling a battery directly, if it's doesn't then you bought a more concentrated solution and need to be a lot more careful with it). Wear gloves and eye protection, never add water to the acid, add the acid to water and you'll be fine.

https://www.*****************/index....-acid-ph-down/

[Ymir]

I guess I can't link to the thread so I'll paste it:

First, do not read any further if you aren't comfortable handling strong acids.

Second, ALWAYS ADD SMALL AMOUNTS OF ACID INTO WATER TO PREVENT VIOLATE AND HARMFUL REACTIONS. Remember acid to Water, never the other way around. Wear eye protection, protective clothing and have the ability to flush any spilled acid off of yourself immediately! If you spill concentrated acid on yo or even worse get it in your eyes, you do not have time to go running to the kitchen or bathroom to rinse it off. Soak any cloth that get acid on it immediately in large amounts of water and neutralize with baking soda.

Now to the topic at hand. Using new clean battery acid fluid properly it is very easy to make many gallons of killer H2SO4, sulfuric acid) pH down for less than $5USD.

Just go to any good battery shop that sells automotive batteries and buy the PRE-MIXED 33% Battery Acid Fluid that is ready to add directly to the batteries. Avoid concentrated 97% battery acid as it is much more risky to deal with. Then get a gallon of distilled water. You will need a clean glass or plastic calibrated container to measure up to 950 ml and as small as 50 ml accurately and to pour it into your 1 liter or 1 quart acid proof storage container.

A mixture of 1 part 33% battery acid fluid to 19 part of distilled water has been the standard formula for a long long time. This gives a strength of approximately 1.65%. Another ratio that is also used fairly often is 1 part H2SO4 to approximately 12.75 parts H2O (I'll give the exact amounts later.) for a concentration of approximately 2.4%. Using the stronger strength means you need to use less pH down to change the pH of a given amount of solution a given amount. However because it is nearly twice as strong, a mistake in the amount you add will cause much more change and possibly damage. Hence, I would recommend using the weaker solution because using a price of $5/L for acid fluid at the weaker ratio and $2/gal for distilled water will give you 20 liters of pH down for a total cost of less than $10USD or $0.50/liter ad it is twice as safe to use.

TO MAKE 1.65% H2SO4 pH DOWN place 950 ml of distilled water into your mixing container. Then CAREFULLY and SLOWLY add 50 ml of Pre-Mixed Battery Acid (H2SO4) fluid to the water. GENTLY stir the pH down solution to mix it thoroughly. You now have 1L of standard strength H2SO4 pH down solution.

TO MAKE 2.4% SOLUTION place 890 ml in the mixing container; carefully add 70 ml of the Battery Acid Fluid; gently stir the mixture and you have 1 US quart of the stronger strength pH down solution.


You will need to figure out how much of your pH down solution to add to whatever you're trying to pH to move it 1 point, ie from 7 to 6.

Here are ball park amounts of how much to add to drop the pH 1 point:

For 1.65% add 5 ml/L and for the 2.4% add 15 ml/gallon. REMEMBER THESE ARE APPROXIMATIONS AND WILL NEED TO BE CHECKED AND MODIFIED TO SUIT YOUR NUTRIENT SOLUTION/WATER.

Sulfuric acid (H2SO4) pH down is more sensitive than commercial pH down solution but it is so much much more inexpensive, most growers who have gotten used to it agree that the savings way out weigh the bother of mixing it up and the need to be more careful how you use it.

This post is a paraphrase of a much longer post of a friend on another forum. He gets credit for all of the general ideas and I bear the blame for any errors. I took his word for the math because it has been too long since I used or studied the formulas.

[SecondAttempt]

Originally Posted by chicken-

For 1.65% add 5 ml/L and for the 2.4% add 15 ml/gallon. REMEMBER THESE ARE APPROXIMATIONS AND WILL NEED TO BE CHECKED AND MODIFIED TO SUIT YOUR NUTRIENT SOLUTION/WATER.

Great post Chicken... I believe the above is incorrect though, probably 5 ml/L of the stronger solution and 15 ml/L of the weaker solution would make good starting points.

[Ymir]

I didn't come up with those numbers and honestly I haven't tried to figure out a per gallon yet, ended up just adding some to my res little by little until I was satisfied and I'll try and get a per gallon when I do a res change.

However, perhaps you misread because the stronger solution says 15ml per GALLON, not liter. If the 5ml/L for the weaker solution is accurate (doubt it) then that would be about 7.25 ml/L of the stronger solution for the same strength.

I would start with a lot less than that, I think that might be in the ballpark of what I used and my water is 7.8PH to start which is higher than most I'm sure.

[SecondAttempt]

I did misread, thanks for the info.

[Ymir]

Originally Posted by ganjourno

Only really needed for certain strains, especially during full bloom and especially for larger plants. If you are 9 per light or fewer I would suggest a little extra epsom, quarter of a gram per gallon. This gives 11ppm extra mg, which combined with the ~50ppm in full-strength jacks, should be plenty.

I've googled around and from the info I'm finding, quart of a gram of epsom salt would = roughly 6.5ppm of mag, 8.5ppm sulfur.

Just wanted to clarify this, if that's wrong please correct me but it seems like it should be more like a little less than 1/2 gram per gallon (13ppm mg)

[Canidae]

Reading this thread is why I joined icmag. I'm having terrible problems with Jack's, and just can't figure out where I'm going wrong. The 18 plants that are now 5 weeks in 12/12 are displaying what I believe is a bad calcium deficiency, and this is the second grow this has happened to. Any help from experienced Jack's users gratefully accepted (Yo Sam, are you still around?).

My setup is as follows.

Two separate 18 plant drip/dtw systems. Each 4 gallon pot uses a 3 gallon perforated insert. Hydro Halo drip rings, each feeding 200 ml. of solution per 20 seconds. Two feedings per day.
Medium: Growstones (recycled glass, supposed to be inert)
Water: RO = 0.00 EC
Lights: One Inda-Gro Par 420 over each 9 plants. (9 plants per sq. meter)
Canopy temp: 76-79
Water temp: 68f
PH: 5.8
Grow room: 18'L x 8' W x 7.5' H
Ventilation: Natural, no CO2. One 4" Vortex fan, one 8" Vortex fan, one 18" oscillating fan.

I've been using the 1 part Jack's to .67 parts Cal-Nit ratio (by weight) and two TBSP of Epsom per 55 gallon res., with a current EC around 0.96.

The plants have dark leaves, burnt tips, some downward drooping (not "eagle claw"), and the characteristic spotted/mottled leaves of cal. deficiency...and I don't have the
experience to figure it out.

Any words of wisdom out there?

[Arminius]

Originally Posted by Canidae

Reading this thread is why I joined icmag. I'm having terrible problems with Jack's, and just can't figure out where I'm going wrong. The 18 plants that are now 5 weeks in 12/12 are displaying what I believe is a bad calcium deficiency, and this is the second grow this has happened to. Any help from experienced Jack's users gratefully accepted (Yo Sam, are you still around?).

My setup is as follows.

Two separate 18 plant drip/dtw systems. Each 4 gallon pot uses a 3 gallon perforated insert. Hydro Halo drip rings, each feeding 200 ml. of solution per 20 seconds. Two feedings per day.
Medium: Growstones (recycled glass, supposed to be inert)
Water: RO = 0.00 EC
Lights: One Inda-Gro Par 420 over each 9 plants. (9 plants per sq. meter)
Canopy temp: 76-79
Water temp: 68f
PH: 5.8
Grow room: 18'L x 8' W x 7.5' H
Ventilation: Natural, no CO2. One 4" Vortex fan, one 8" Vortex fan, one 18" oscillating fan.

I've been using the 1 part Jack's to .67 parts Cal-Nit ratio (by weight) and two TBSP of Epsom per 55 gallon res., with a current EC around 0.96.

The plants have dark leaves, burnt tips, some downward drooping (not "eagle claw"), and the characteristic spotted/mottled leaves of cal. deficiency...and I don't have the
experience to figure it out.

Any words of wisdom out there?

Running a similar setup with Jacks, and Ebb and Grow. I do not measure my salts by weight, but by volume. Iirc, it is 3/8 tsp per gallon. You can see the results in my thread. The first room just started Week 8 today. Insane resin production, and nothing but Jack's.
My first thought, is you may have a Ca deficiency, due to the generally low EC that you are using. When I was using RO, 1.2 - 1.6 from veg to chop killed it. At my new site, using city water that is 0.6 - 0.8 EC from the tap. I was worried that I would burn tips at 2.4 EC, but nothing, not even the "Claw". Maybe your ratios are off? Try to measure by volume, and not weight. The raw salts will absorb moisture from the atmosphere, and thus increase their weight. For example, I use 10-12 Tbsp per 60 gal tank of each, in equal volume, but they are not equal in weight. The Cal Nitrate is obviously less weight by volume based on the size of the granules.

[Medium Pimpin']

How established are the girls and their root zones?
Seems to me they might need more feedings.
2 x 20 second cycles seems awfully under watered to me.
Grow stones don't hold water all that well from my experience.
Also, did you rinse the stones?
They def come dusty, maybe that's causing your root zone ph to rise?
Some pics might help.

[Ichabod Crane]

Try giving them some cal/mag ferts just before flower. My chem strains do the same thing in flower but out grow it. So they get some cal mag before flower.

Drop the EC to 1.1-1.4 also and feed more often. If the media is drying to much it will shift the PH in the media and cause this as well. More feedings will help with the PH drift.