I have tried it two times. First in autopots. I did not have much luck with it. It fouled the valves and fell out of suspension. I am not sure why it did. I used it along with liquid silica (Silica Boost from Bloom City), See what I mean
I tried it again with a top fed plant I have now. I am in coco so feeding every day. During the 5 day period I used it the runoff pH dropped from 6.3 to 5.8 and PPM increased from1100 to almost 1900. The plant wasn’t taking in something so I stopped.
After of couple days of straight 321 I will try MKP formula.
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I bought a 1# generic version of monopotassium phosphate for $18 + a couple bucks shipping
I guess I’m just lazy or dim, but I have been running Jacks 321 successfully for a year or more and I don’t use anything else. I have silica but don’t use it because the main stalk and branches are already thick as can be and I don’t see the need. Nor do I do the MPK once I switch to flower. I also just measure the powders with measuring spoons from Walmart. 1/2 tsp A, 1/4 tsp Epsom, 1/2 tsp B.
Could I improve the yield if I fiddled with extra products during the grow. I am sure I could. But I already get enough out of the tent and don’t have any issues to contend with.
I am not discouraging anyone from using whatever they want because I know how fun it is to try to get that extra ounce, but If you really just want to keep it as simple as possible then all you need is the Jacks two part system with Epsom salts.
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Eww! It looks like Dawn dish soap that was squeezed out into the sink and just left there to coagulate.
I’m glad I didn’t find it and won’t waste my time on finding it now. I was happy with the results from just the MKP so I’ll stick to that albeit I’ll probably run it a little longer that they say like I did last time.
And now that you posted here I remember reading this in your journal not too long ago!
I’m gonna have to blame my lapse in memory on the Northern Lights I was trying out for the first time last night! Not bad for an auto-flower! 
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Both are a mystery to me. I am going the MKP route. Speaking of memory lapses I think I double ordered Bloom. Our flowers will love it.
