Fertilator is a tool gives you an idea of how much a certain amount of fertilizer will add to your aquarium. The tool ignores any current levels in the aquarium already. I would avoid adding the suggested levels to the aquarium and follow EI or PPS to get an example of how much fertilizer to dose into the aquarium.
I agree with what Brilliant said. There are many different ways to approach fertilizing. The Fertilator doesn't directly give you a specific plan, it just makes it easier to follow certain plans (or make up your own) by telling you how much of a supplement/chemical to add to get to reach the desired ppm.
Sorry, forgot to mention that the recommended ranges (the numbers below the boxes in the Results section of the Fertilator) are the recommended levels in the aquarium, not how much to add. So, if your aquarium has 4 ppm NO3 currently, and you want your it to be in the "recommended range" of 10-20, you'd add 6-16 ppm NO3. I've had mixed results with trying to keep my aquarium in the "recommended" ranges though, but I'm not sure why it works for me sometimes and not other times... If you're a beginner it's probably best to just follow one of the common fert schemes.
I have a question regarding the Fertilator. In the "Calculation type box": Find Percent Of Nutrient In Water. I then go to "Nutrient" and from the drop down list I select PO4 in Fleet Enema. I want to make a fert solution of 1000ml(1 Liter), and I have a 70 liter tank, my desired ppm is 2ppm. Whats confusing me is where it says "Amount of dry compound added". Since Fleet Enema is not dry, what do I put in that space? Is it what is stated on the box. 19grams of Sodium Biphosphate + 7 grams Sodium Phosphate= 26 grams. The fleet enema comes in a 133ml bottle. So is this correct? I put 26 grams in that space? Thanks for the help in advance. Just to say one more thing, Before I started dosing Fleet Enema, my tank walls were getting covered in GSA and a bit of Staghorn as well, now it has nearly dissappeared. My last fert mix was done using the Fertilator and I added 2 bottles of Fleet Enema to make a mix of 1 liter of ferts, by adding the grams on the box together. From what I have read elsewhere, I have way over dosed Fleet Enema??? I'm confused?? Please help.