The PH for the feed water in coco should always be around 5.8 ....not higher. Not trying to say it wouldn't work, but the proper coco ph is 5.8. And as far as using Floranova with "the lucas method", that isn't possible.... because "The Lucas Method" is when you use only the Flora Micro and Flora Bloom throughout the grow (no Flora Grow necessary). The ratio for soil is 8ml Micro/ 16ml Bloom.... and the Lucas Method ratio in coco is 6ml Micro / 9ml Bloom (and YES to cal-mag if you're using RO).
Actually, the 6ml/gal micro, 9ml/gal bloom is "Heads modified" Lucas formula. Or the H3ad formula. But also calls for some epsom salt, as the extra micro is already supplying the extra Ca needed for coco.
I Ph to 6.0, find it to be best, and i've been growing in coco since it hit the shelves.
Even though Lucas has listed amounts to use with 1parts, I wouldn't call them Lucas formulas either
But anyways, starting with RO water growing in coco:
3-4ml/gal of calmag, and 4ml/gal of EITHER maxibloom OR floranova bloom works just fine. And I would still much rather use a "grow" formula for veg and the stretch. Peace