Do they tell you to add more nute mix in between monthly tank dumps?
Yeah, I saw that. A little exxy on the per litre basis. Can you cut costs by buying bigger containers? Anyone else local to you have a better deal?
There's some other things you're using which you might be able to do without. I have cut it all down to only nutes, H2O2, pH Down (phosphoric acid type for flowering, nitric acid type for vegging my mums) and a phosphorus supplement which only gets used in wk3 of flowering.
Canna would love to sell me their VERY expensive 'Rhizotonic' root stimulant (about $50-60/litre or more), but if I don't induce root diseases by overwatering and keep pathogens in check with H2O2, I just don't need it.
Hydro shops sell tons of 'magic sauces' which often do nothing or don't do enough to justify their cost. I started off years ago by trying several things as suggested by salespeople or other well-meaning folks and just stopped using them to see if there was any difference. More often than not, there wasn't enough difference to justify the cost.
i could buy 20 litre containers but i dont have the funds to do so, its quite often a stretch to get to a 2litre when i need it.
i dont use the whole range i dont think everythings needed,
i use grow bloom and boost plus super drive/thrive
plus i use liquid silicon occasionally as a ph up
on your previous info though, i take it to a simpler level
you have 10 litres of water in that water there are the 3 main nutes
10ml n
10ml p
10ml k
so you use 5 litres of water and top it back up to 2.0 ec
but the plants have taken nutes and your left with
7ml n
3ml p
4ml k
so the ratios are way out there, but youve added water and got it back to an ec of 2.0 in relation to the water,
you still have 5 litres of water to top up but instead you fill this with ec 2.0 with 5,5,5 because its half of the original value
so then you have 11,8,9
these ratios really arent that far out and less so than not topping up with nutes.