Plants need more than just fertilizer. Primarily they need light, nutrients and carbon dioxide. Many refer to these as a three legged stool. You want that stool level so balancing those three things is the key.
Plants need light. I'm guessing you have low light based on the plants that survived. By the way, anubias should not be planted in the substrate. They should be attached to hardscape. What type of lighting do you have?
Since you are not injecting CO2 this one is pretty easy. Just continue using the Excel following the directions on the label.
The amount of fertilizer you add is based on several things primarily light, CO2 and plant mass. There are 12 basic nutrients plants need to survive. Those nutrients should ideally be supplied at the correct ratios to one another.
Imagine a bucket of 12 apples representing those 12 nutrients. Healthy apples indicate an adequate nutrient level for each element. Rotten apples indicate nutrients that are too low or too high. One bad apple will ruin the bucket. Several bad ones will ruin it even faster.
It sounds like you have a bucket (aquarium) with several bad apples (nutrients). Rather than root around the bucket searching for bad apples, simply empty the bucket (do several large water changes) and add fresh ones.
How we add apples to the bucket are referred to as dosing methods. There are three popular methods PPS (perpetual preservation system), EI (Estimative index) and non CO2 methods.
Since you have Excel I would eliminate the non CO2 methods leaving PPS or EI. Excel does promote growth considerably when used properly. Of those two methods I personally prefer the EI method.
The EI method was originally devised to eliminate frequent water testing to balance all those nutrients. It's the easiest to use and the most effective in my opinion. Here is a link
that describes the basics of this method. The EI method relies on emptying the bucket on a regular basis. This not only allows us to keep nutrients at a level that never limits plant growth but also removes harmful things and adds beneficial things on a regular basis.
Since you have such small tanks I would use solutions for dosing. You can try to assemble commercial solutions or make your own. The DIY route is FAR cheaper and quite easy. About $25 will get you all the fertilizers you will need for the next few years! Here is another link
that explains how to make basic nutrient solutions.