Do you have a list of these ratios that you feel are important?
Due to the competitive nature of the essential metals, it's necessary to supply them at ratios plants require. In this case, the tap probably has enough Fe and Mn but the amount of Cu, which is 3x Fe, may be causing problems. One way to rectify this disproportion is to add more Fe, Mn, etc so that they are in better proportion. However, at 0.03mg/L of Cu, adding enough Fe and other metals to improve the ratio would most certainly result in toxic concentrations of heavy metals to animals, even if the plants grow much better as a result. There is a trade-off to be made.
One of the most important confounding factors is the role microbes play in the chemical interactions as they also require the very same metals for their growth and health. So adding fertilizers, especially the trace elements, is actually providing nutrients for the plants, algae, and microbes. It also provides them to fish and other animals. Since we do not know what microbes will colonize and their nutrient requirements, it's difficult to say what is necessary for plants and what's necessary for the microbes. So fertilizing with trace elements are really for these two classes of organisms. It's possible that the microbes that colonize the aquarium require more Cu or are just more tolerant to it. If they require more Cu, then Cu will gradually reduce. The general idea here is that microorganisms play a very large role in tank health and in helping to keep the water safe for both plants and animals. So even if there is an ideal nutrient ratio the plants will grow best in, microbes may change the ratio as they utilize them for their own growth. However, when they die, they will provide the nutrients back to their environment. Unless they are vacuumed and removed.