GH decided to get in on the action of the Lucas formula and designed a new nutrient copy of it (but added some fulvics/humics too for good measure) and then patented it. 8mL/gal is the exact Lucas formula.
i didn't like it. mixes up too thick for my liking and i had a lot of crap settle at the bottom of my res even when using a waterfall in it.
I'm really starting to think the high Ca can be problematic with really high micro contents like that. Plus... is it really even possible to get micro deficiency when using micro at the recommended amounts? I feel like doubling down on all these chelated micros and Ca cant do anything good for your solubility. This is also my suspicion on why Lucas requires RO (besides just the 'simplicity'), you simply cant have any hard elements in your water or it'll effect solubilit, uptake and pH (at the high end of hard minerals). Only reference ive seen of 'safe' things to add to lucas is PK booster at the end, and PK should be extremely soluble (hell, still might push out some hard elements tho).
Hmm, usually by the time ive got SI/cal-mag/micro all mixed (semi-hard water, mixed to about 120ppm before micro) I already get a bit of precipitation, and I havent even gone over 5ml/gal for micro so far (and using fractions of recommended SI/cal-mag). I can't imagine running the full 8. I'm also running almost... 2ml/gal pH down I'm sure this does no good for the calcium content of the water (locking it up maybe). If a mineral/element drives up your pH, it will precipitate at high pH (and opposite for acids). So I would almost have to start adding acid before micro which i think is a big no-no?
Our city water was coming out unusually hard a few days ago (the city 'bumped' a treatment tank and flushed a bunch of lime/carbonates into the water). Added a bunch of pH up (like maybe 5ml to a cup of water) and got precipitation. So... add in a bunch of other hard alkaline minerals and it definitely reaches some limits there.
I'm pretty afraid to add that much more calcium basically, lucas might have just the right amount of Calcium, but it's gotta be on the high end. I'm also to stubborn to switch to R/O, but it wont do me much good anyways because i want to run SI (for heat resistance). Already at 130ppm Ca with my current mix + tapwater, if i ran 8ml of micro Id be at about 200ppm Ca (lucas caps out at 140). I'm realllly starting to like the idea of a low-calcium low-nitrogen base. These both seem like easy enough issues to identify and fix without having to change your res.
Just for fun- here's what it took to pH my final mix. came in around pH 6.5, took maybe 1.5 ml/gal ph down. Used the phDown SDS to find out the actual NPK (elemental ppm: 3-25-0 ppm at 1ml/gal), so i'm also adding a shit ton of P (extra 35ppm almost).
You can see the first pH 'jump', that's when i changed out the rez. Also interesting to see the CO2 content when I filled the new rez (I normally cause little bumps in CO2 with my breath, but tent was actually closed most of the refill). The final mix gassed off CO2 for almost 2 hours, best guess is its the mix neutralizing the carbonates and/or the bennie microbes.
EDIT: I also decided to leave my 'broken' veg mix where it is- it ended up being low P, but I pretty much just evened it out with all this ph down.