hi surf and grow,
i have been doing some reading on this topic.i am just starting out with jacks.
while looking around i found this site from colorado. unfortunately i cant figure out how to sign in but maybe youll have better luck.
anyway
this site is doing a bit of work deconstructing hobby nutrient lines and replacing with more real ag fertilizers for years now. in this link they break down non caanabis industry cal mag products by water type. its breif and not super in depth but its worth a look. if you stroll around the site youll find their formulations for jacjs and peters are slightly different program.
1.89g/gallon Peters Professional 5-11-26
1.84g/gallon Yara Liva CALCINIT Calcium Nitrate
0.94g/gallon Magnesium Sulphate (Epsom Salts)
Mixed together this will deliver PPM 100-24-108-93-25 (N-P-K-Ca-Mg)
they also go int orunning a couple different jacks and peters ready formulations. site is interesting for sure.
maybe youll find something they are doing helpful. just thought id throw it out there, it made me think of your post considering a lower ratio of jacks for a lower salt content without watering down.
http://www.centennialseeds.com/2013/08/21/peters-15-5-15-cal-mag-special-water-soluble-fertilizer/
Ive Just put two harvests through with Jacks with dismal results. My Jacks was definitely deficient in something. The first run produced sick plants in flower although it rocked the veggies. They were stunted and small with weak stems and small flowers. Very high tricrome content and it made my GDP look and taste better then ever before. I ran it a second time hoping to fix what ever was wrong. Same scenario. Plants rocked all the way through veg and got deficient as they headed into flower. 4 weeks I left them in flower with them doing almost nothing. Then I decided to try my old formula to see what would happen. Within 4 days of watering with AN and GH nutes the girls had stood up and started producing chuncky buds with trichs and hairs. 4 days! WTF. I used the 3-1.8-1 mix and I will not use Jacks again. It stays in coco like no ones biz! My ppms where high and my EC was around 3 on the drain water. Now that Im back to the regular formula everything looks great just a lot smaller flowers. DONT EXPERIMENT ON YOUR WHOLE CROP! Even with the bad product I still pulled 10lbs off 8 lights. Not sure what ill get this time but Im even more stoked for the next run because everything will rock at full potential like it always had. I dont know why I switched my formula. I wanted to experiment but I think this shows that if your shit works dont fuck with it. Jacks is not meant for coco!