I am thinking about switching to dry fertilizer for my 40g breeder heavily planted low-medium light NO co2 aquarium. 6 months ago I switched from the seachem ferts to easy green all in one fert. Overall I saw much better results with easy green but the nitrogen in it had me doing extra water changes. Also now that my plants are grown in I am dosing much more which can get expensive if I keep using it. If I switch to dry ferts will csm+b and potassium sulfate be enough to start? I keep my aquarium around 20ppm nitrate and I am assuming I have enough phosphate due to the aquarium being heavily stocked and heavily fed(this is just a guess I've never tested phosphate). Also the shipping is expensive so I want to order enough for at least a few years. How much will 400grams of say csm+b or 400 grams of potassium last? Should I get 2 bags? Lastly should I also get some iron because I will be getting red plants in the future and what type or iron should I get?any help/advice is greatly appreciated.