Athena's feeding charts are really solid - just follow their recommendations and adjust based on how your plants respond. Start at 50-75% strength and work your way up. Watch for any signs of overfeeding!
They have easily access instructions and feed charts on athena.com. They have you covered. You'll always need to adjust from instructions due to local variables being different for everyone which will impact 'max' photosynthesis per day in your garden, which will in turn impact exactly what oyu need to provide in building blocks (nutrition). temp, RH and ambient co2 being the biggest factors... assuming light is powerful enough too.
Their ratios should be good to start.. they didn't re-invent the wheel. They are using existing knowledge that numerous other companies make use of for much cheaper. So, you may need to slightly tweak exact amount of each fertilzier, but mostly will be about finding the right overall concentrationt hat doesn't cause problems over 3-4 months (will need different formula for vege vs flower phase and multiple ways to do that, too)
--- side notes
Check out jr peters "jacks 321" setup .. .it's virtually the same as athena's "pro line" but about 1/4th the price (120 vs 420). and it mixes more gallons per 25lb bag, too.
Athena is not cheap. The pro line is at least 4x more expensive and the blended is probably closer to 20x more expensive than equivalent options available on the market. This is a company that charges a premium for their name and zero quality difference from other options.
Southern ag, masterblend, cropsalt, megacrop, kosher-something, JR Peters -- they all have a similar setup to the pro line. None of these companies invented the wheel. This is all based on existing knowledge that is not proprietary. I don't know which is cheapest, but the best ones are the simplest. The cheesedick options put the trace elements in one of the generic components, like the Calcium nitrate (the 14-0-0 to 15.5-0-0 bags) or the epsom salt (magnesium sulfate). This way you can't buy the generic calcium nitrate for much less. e.g. yaraliva has a 50lb bag for 35, or you can pay 140 for athena's 25lb bag, lol. 8.5x more expensive for the exact some molecule in slightly different concentration...
The base product Jacks "Part A" is th eonly branded item you need to buy. the calcium nitrate and magnesium sulfate can be the cheapest generic local options and be the exact same thing. i just about a 8lb bag of epsom salt for 7 dollars. jacks wants 50 for a 25lb bag... 2x more expensive for a name and 8lb pairs better to a 25lb bag of part a relative to dosing (1g : 3g).
More generally, a complete diet of fertilizer for soilless/hydro context should be about 4cents per gallon mixed (other regions of earth may be more/less)... anything over that is ripping you off. There is nothing special about the expensive stuff. Just some greedy people running the company with some sociopathic tendencies, and just enough lack of integrity to do so.
Reverse Osmosis (RO) water and, follow the feed charts for your product (Pro or Blended), and closely monitor EC and pH levels. Everything else depends on your own growing knowledge base. Don't particularly want to go full blah blah blah mode and put you to sleep.
Sometimes you gotta do your own legwork. 📖 📕 📘 📗 📓 📚
