Short and simple.. for basic plant foods and liquid co2... they are a very good brand, Leaf Zone is one I would use...
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That is the long and short of any answer you will get because there is NOTHING short and simple about getting the levels right and what to use. Not all plants make use of liquid foods, some like Amazon Swords make better use of root fertilizers.
Dosages will be difficult to work out because the dosages on the bottle don't take into account how many and what species of plants you have so you may end up under or over dosing on one or both treatments and causing a massive algae problem. All I can say is DEFINATELY don't overdose the Co2 lol!
I would say if keeping it simple, get those products and have a second post in the plant section of this forum and when you know exactly which plants and how many of them you have, someone can try helping you work out the best ratio between fertiliser, co2 and lighting. Those three all have to be in balance or you will have problems, mainly with different species of algae...