Hey man. Sorry for your luck on the puny plant. Been there too many times. I strongly urge you to start your bean in Promix with added perlite and that is IT. Then ph water at 6.0 to use and you should be great.
Then you can take your other hotter mix and transplant to it after about 3 weeks in the more plain mix mentioned above. I wouldn't make layers. If you want to use all that stuff cool, just keep it on the light side and proportion it well and mix it all up and wet it down. Make sure your ph is spot on BEFORE transplanting into it. You have the probe so it should be easy.
The problem with the layers in my opinion is varying levels of nutes and ph is not stable at all. You need something more uniform in ph.
And instead of doing a traditional full scale transplant do what is called a tier transplant.
Get yourself some plastic/styrofoam cups at least 32oz in size.
#1Cup the bottom completely out of one.
#2Poke/drill/burn drainage holes into a separate cup.
Take the first cup and drop it down into the second. Fill with first mix mentioned and plant bean.
Grow them out in there with plain ph water only for 2-3 weeks or until they show sex.
Then when you're ready to transplant simply yet carefully pull the first cup out(which is the one with the bottom cut out)
Now you can plant the young plant cup and all into the bigger pot with the stronger second mix.
The roots will grow out into the bigger pot and there ya go.
Hope this helps and let me know if you need any other help.
