Question for the powder people, Jack's people and/or Tint Eastwood

I'm going to do a test run, start to finish, with the following stuff.



As you can see, it is complete except for sulfur. So my question to you knowledgeable ones is this: Based on these numbers, would it be better to supplement the sulfur with magnesium sulfate (Epsom) or Calcium sulfate (gypsum), or would you use something completely different ? I can get both for really cheap and both are easily available to me. So which is it? One that will give more calcium in addition to the sulfur or one that will give more magnesium?

Thanks for reading.

I use the 2 part Jack’s 321 but I’m new to it. I‘m not familiar with the one you have shown here though. There’s 4% calcium listed on the package; I’m not sure if that’s going to be enough but since it has some calcium, I’d try the epsom salts. I use the Walmart brand with my 321 nutes.

Thanks for the reply. I am trying to figure out which is the more valuable of the two choices in regards to the plant's general needs. Like you noticed, it does have 4% calcium, and it also has 1.8% magnesium. Since I have to supplement sulfur regardless of what I use, I am wondering if bumping up the magnesium level with magnesium sulfate would be better vs. bumping up the calcium level using calcium sulfate. Currently I am using magnesium sulfate and the plants are happy, but I want to know for sure which is the better option, considering that my tap water is very low in both calcium and magnesium.

It doesn't look like the readers here have much to say on this topic so I may just have to end up experimenting with both. Perhaps I can report back on which works best for future readers.

I have also used the 2 part Jack's and have been generally happy with it, although the 2 part Megacrop gives me better results. I really love the Jack's blend that I have listed here though, in spite of the fact that I have to add sulfur. It is the most soluble powder that I have used in a very long time. It dissolves within seconds and there is not the slightest hint of any particulates. It also stays in solution perfectly long-term. Great stuff.

What do you plan on using in flower? Why opt for something like this over the 5-12-26?

I can say that the Jack’s finish 7-15-30 didn’t work at all for me. Blue dyed garbage in my setup. The plants would barely take it up so I had very low PPM drop the 4 days I let it run. I used more PH up in 4 days than I used in the previous 4 months. It made me uneasy about trying the other products in their line. The 321 is great but it was like the finish was made by another company.

i use jack's RO with well water. i add 1 g/gal of epsom for Su.

twentyeight.threefive said:

What do you plan on using in flower? Why opt for something like this over the 5-12-26?

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I like trying new stuff. In this case I found the 2.5-1-2.8 ratio to be interesting. I'll be using this one for the entire cycle; start to finish, with a supplementation of a little extra Phosphorus for the first 3 weeks of flower.

5-12-26 works fine. It costs the same as the 15-6-17 in my area and both magnesium sulfate and gypsum are cheaper for me to buy than calcium nitrate, which is needed for the 5-12-26. The difference isn't that much though. I just like trying new stuff and this one is more rapidly soluble than the 5-12-26, which I like.

As I wrote an above post, if you like 5-12-26, you might be interested in trying the Megacrop 2 part. It gave me better results. Same ratio for the macros.

MustGro said:

I can say that the Jack’s finish 7-15-30 didn’t work at all for me. Blue dyed garbage in my setup. The plants would barely take it up so I had very low PPM drop the 4 days I let it run. I used more PH up in 4 days than I used in the previous 4 months. It made me uneasy about trying the other products in their line. The 321 is great but it was like the finish was made by another company.

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You are not the first person to post problems with that mix. The negative reviews were one of the reasons that I chose not to try it.

rkymtnman said:

i use jack's RO with well water. i add 1 g/gal of epsom for Su.

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Easy choice for that one because the RO has so much calcium already. What do you think of that mix? Is it working well for you?

MustGro said:

I can say that the Jack’s finish 7-15-30 didn’t work at all for me. Blue dyed garbage in my setup. The plants would barely take it up so I had very low PPM drop the 4 days I let it run. I used more PH up in 4 days than I used in the previous 4 months. It made me uneasy about trying the other products in their line. The 321 is great but it was like the finish was made by another company.

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ya it stained all my dehumi filters and my ac blower wheel and carbon filter. never using anything blue dye from them again. i was thinking of mimicking the ratios of the bloom and finish adjusting the 321 ratios but idk if thats worth experimenting with. i do get purple leaves beginning of flower cause of the low P.

i like jacks 321 though. the light brown tint is pretty clean.

this 15-6-17 is for clones isnt it? i tried the ro formula with my tap and it gave good results. just the blue dye staining all my equipment made me stop using it. it also was missing sulfur but had everything else in it. i cant remember if i gave epsom salt with it though.

does this have blue dye in it too like blossom booster and finish and ro formula?

Hope these breakdowns are of some help.
If you add epsom, for example - Watch the ratio of Mg to Ca. Usually Mg is lower than Ca.



Older stock seems to have more dye than the new stuff.

Excess Mg may lock out Ca and/or K

newbplantgrower420 said:

ya it stained all my dehumi filters and my ac blower wheel and carbon filter. never using anything blue dye from them again. i was thinking of mimicking the ratios of the bloom and finish adjusting the 321 ratios but idk if thats worth experimenting with. i do get purple leaves beginning of flower cause of the low P.

i like jacks 321 though. the light brown tint is pretty clean.

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You get a light brown tint with the 321? Shit mine is clear. I’m new to it though so my supply is pretty new.
Must be like @TintEastwood said, “new stock has less dye”; I like that, fuck the dye.
After trying the finish and hating it, I‘m just going to use the 2 part and keep it simple. There’s a lot of products in their line and I’m thinking I can do without most of them.

rkymtnman said:

i use jack's RO with well water. i add 1 g/gal of epsom for Su.

Click to expand...

My first run with this and I had some great results so far !

MustGro said:

I can say that the Jack’s finish 7-15-30 didn’t work at all for me. Blue dyed garbage in my setup. The plants would barely take it up so I had very low PPM drop the 4 days I let it run. I used more PH up in 4 days than I used in the previous 4 months. It made me uneasy about trying the other products in their line. The 321 is great but it was like the finish was made by another company.

Click to expand...

Ya I’m feeling that sentiment right now I’m in last 1-2 weeks in flower I switched to the finish and now they aren’t happy my roots where perfect White full and now after the switch they don’t look as happy it’s weird also where my nozzles are misting the roots they are yellowing slightly so I was thinking I did something but nothing has changed only the nutes switched from Jacks RO to the Jacks Finish I don’t think I will use this again

Edit : since the discussion is about Mag I do have a question .... let’s say my target ppm is 800 and I’m using Jacks what percentage of mag should that be so do I figure 10% - 20% ?

Rdubz said:

My first run with this and I had some great results so far !



Ya I’m feeling that sentiment right now I’m in last 1-2 weeks in flower I switched to the finish and now they aren’t happy my roots where perfect White full and now after the switch they don’t look as happy it’s weird also where my nozzles are misting the roots they are yellowing slightly so I was thinking I did something but nothing has changed only the nutes switched from Jacks RO to the Jacks Finish I don’t think I will use this again

Edit : since the discussion is about Mag I do have a question .... let’s say my target ppm is 800 and I’m using Jacks what percentage of mag should that be so do I figure 10% - 20% ?

Click to expand...

I made it 4 days on the finish before I dumped it, my plants really didn’t like it, they didn’t take up more than maybe 50 ppm in that time. Never used the RO, but I’d like to as my water is pretty low at 55 ppm(.1ec), but I’m afraid to buy another bad product from them. There’s a lot of products in the line too. Another thing that pissed me off about the finish was it had no calcium in it. There’s no mention of this in their ads, that I remember anyway, but it does mention on the finish package that you should add a calcium supplement; like theirs…
@TintEastwood ‘s charts are in grams per ml, I think anyway. So the 321 is listed as 89 g/ml mag in 728 mls. So it’s less than 10%, just over 8% according to me but I’m pretty stoned right now…
I have been running the 321 at about 70% of the recommended dose of epsom in veg because of the mag. So like .7 grams per gallon instead of the .99 Jack’s called for. Don’t know if it was necessary to cut it back or not, but read it in a post so thought it made sense. I’m running their ratio now. 3.78A, 2.52B, and .99 of epsom.

MustGro said:

@TintEastwood ‘s charts are in grams per ml, I think anyway. So the 321 is listed as 89 g/ml mag in 728 mls. So it’s less than 10%, just over 8%

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On my sheets the product measurements are in grams (powder) or ml (liquids) per gallon.

Elemental PPM is per gallon.

The 89 is PPM per gallon.

Ppm is calculated - derived from the percentage printed on the product label.

Here's an example of bag percentages calculated into elemental PPM.
(For 1 gram of 5-12-26)

So @TintEastwood according to that last post of yours, just the Part A is 17PPM mag, or 6.3%.
I see there’s no calcium in it either, just like the finish. Not a big deal with the Part A, but didn’t want to add a bunch of calcium nitrate to the finish when I used it, so I was kinda stuck.
I understand what you mean about picking your epsom sources as the ratios will change with manufacturer. You have any favourites? I notice Jack’s brand of epsom isn’t cheap.

No need to buy name brand Epsom. Any Epsom salts brand will have the same breakdown.

Same with the Part B - calnit. Generic brands are ok. Except their N and CA percentages can vary between the different products.

MustGro said:

So @TintEastwood according to that last post of yours, just the Part A is 17PPM mag, or 6.3%.
I see there’s no calcium in it either, just like the finish. Not a big deal with the Part A, but didn’t want to add a bunch of calcium nitrate to the finish when I used it, so I was kinda stuck.
I understand what you mean about picking your epsom sources as the ratios will change with manufacturer. You have any favourites? I notice Jack’s brand of epsom isn’t cheap.

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So on Jacks feeding chart they don’t show that you should use any calcium it only shows to be used with Epson for the mag but why would they want u to run with out and is this why I’m having problems now because no calcium , does not having calcium have a negative effect on roots?

Edit: I was referring to the finish product actually so here is there schedule

Here I'm using also some calimagic to adjust ppm levels.
321. Most use more or less calnit to adjust the Calcium. Which affects N also.