Nice Olive. You purchased a nice consolation prize.
Aqua Bonsai - is just hydroponics by another name. Check your local hydroponics shop, look for the 2 component liquid fertilizers, Component A will have the nitrates and calcium supplements, component B will have the sulfur as a small but crucial part of the nutrients. Sulfur and Calcium, when they meet in solution form an insoluble rock known as gypsum. So they are added in separate solutions, usually one in one week, the other the next week. For bonsai I would use about half the dose rates recommended for marijuana, or hot peppers, the ''stand in'' for marijuana in grow shops in regions where marijuana is illegal. Why grow shops? Marijuana is an economic crop where they have invested the time and money into researching the details of hydroponics. They have the ''current'' information.
Honestly, plants can not read the label, you could just use any modern formulation of water soluble fertilizer, it doesn't have to be labeled for Aqua Bonsai, or Bonsai or Marijuana for that matter. Nitrogen is nitrogen, and with a few exceptions, it doesn't matter if the fertilizer lists your particular plant. Just don't over do the concentrations. You want to keep nutrients dilute for bonsai, you don't want rank, excessively vigorous, rapid growth. By modern fertilizer I mean one with nutrients in the proportions that the plants actually use. Ignore any information from RBG at Kew, the last time they updated their fertilizer info was 1887. An ideal modern fertilizer would be roughly 12-0.8-2 with Calcium around 12 and Mg around 3 if your water has low total dissolved solids. If you water is heavy in lime, high total dissolved solids, around 600 ppm, you want a lower rate of calcium and magnesium, perhaps 4 and 1. The additional nutrients needed include iron, manganese, copper, zinc, boron, & selenium, the full compliment of micro nutrients.
Sulfur is a needed nutrient, if your Nitrogen is 12, the sulfur should be around 3. Sulfur is very available in the environment. If trees are grown outdoors in urban and suburban environments, acid rain will contain enough sulfur that you may never have to worry about it. Most clay soils have plenty of sulfur. It is in synthetic, inorganic mixes, and indoor or greenhouse growing situations, then sulfur supplementation should be done. Once every second or third week you can use Epsom salts, from the local chemist's, it is Magnesium Sulfate, normally sold as a soaking solution for feet, or other aching joints. About 5 ml by volume per 4 liters of water is a nice, a dilute but effective dose. Use this as your source of sulfur nutrient.
Exceptions: there are exceptions for extreme calcifuge species (calcium hating species) for example blueberries (Vaccinium sp) and carnivorous plants. One can also tweak fertilizer for azalea - it is a ''mild'' calcifuge. This topic should be saved for the ''deep dive'' either into Vaccinium or Azalea. Another situation if you have very hard water. Over 1100 ppm total dissolved solids. For very hard water you start by avoiding calcium supplementing fertilizers. Again, there is more, but we'll save that for the deep dive into a specific problem.