Your tank does not look heavily planted to me and then a lot of the plants look like slow growers. I would try to modify the ei dosing a bit. for my 75 gal tank I would dose micros, potassium and some phos, 2x a week, med light and diy co2.
For my 20L tank with 6hrs t5no light, no co2, and planted a little less than yours I dose potassium and micros 1x a week or 1x every other week. I use osmocote root tabs and it is med stocked. My plants are growing fine, not fast, but fine.
my personal feeling with gravel vacuuming is that it depends so much on the depth. I wasn't vac the gravel in my tank, then I measured the depth. varied from 1"-2", I personnaly don't think this was deep enough to sort of keep the crap out of the water column, 2" maybe but not 1".
My only real point to this post is say that I would look at what some really lush tanks are doing as far as co2, ferts, etc and then adjust as you see fit.
If you have less light, less co2, less plants and more fish---why do you need the same ferts? but the whole idea of ei dosing is you are never short any nutrient so the things like potassium and micros I would still dose close to or the same as suggested.
20L Daughter's Tank: 2 Bolivian Rams and Threadfin Rainbowfish
40B Inlaws Tank: 4 Bolivian Rams and Guppies
75 Main Tank w/ sump: 5 Glossolepis pseudoincisus, 5 Melanotaenia boesemani, 10 Melanotaenia praecox, 5 Melanotaenia lacustris