i recommend using a smaller container( so you will have a fresh batch every coupe months) maybe 1 liter solution, 1 liter solution at 15 ml/ dosing means around 65 dose over 2 months everyday.
like what everybody is saying, follow the recommended mix and then tweak it as you go depending on you plants progress, overtime you will encounter deficiencies.
65 gallon RIMLESS DSA NEO
fluval fresh and plant 2.0 36"
fluval spec 5