This is a discussion on CO2 supplemented tank - Help fertilizing within the Beginner Planted Aquarium forums, part of the Beginner Freshwater Aquarium category; -->
I have a 450 litre tank and will be a high tech and heavily planted.
I just ordered
7x Vallisneria spiralis - ...
Can I ask what fish/animals you are intending to keep in this tank? I have noticed a lot of issues that come from someone setting up a tank and only then trying to find fish that can thrive in the environment that has been created. It's always healthier, safer, and cheaper to have a good idea of fish/animal population first, so you know what kind of environment is needed for those animals.
The same concept applies to the food selection... first need to know what you're feeding, then base food selection on what those animals require for proper nutrition.
And... CO2 use, fertilization, etc. also are affected by the population of animals in the tank... how much waste will there be to feed the plants?