There are two main groups of Ferts, the first is Macronutrients – Nitrogen Potassium Phosphorous, and these are usually supplied within the water through both the fish and feeding, but with lots of plants you will need to add extra.
The Micronutrients are everything that aren’t macronutrients, so Iron, Boron, Calcium, Chloride, Copper, Iron, Magnesium, Manganese, Molybdenum, Sulfur and Zinc. These can usually be dosed with commercial fertilizers.
Great fertilizer products, will work well, but they are expensive to maintain, if you bought them in bulk you could definitely save substantially.
Make your own
Sure you could make your own fertilizer, it is best to have an idea of what breakdown of nutrients you want for your fertilizers and to make sure the chemicals you add are not harmful to your fish.
Yes we’ve all heard of it, the infamous Sears and Conlin recipe that struck up a storm - Poor Man's Dupla Drops. This definitely does work and will fertilize everything all at once, it is extremely cheap and can be made up in a matter of minutes. So why doesn’t everyone use it? I guess some people prefer to stick to the commercial product lines. Some stores will now stock the basic dry mix at a very cheap price, be sure to look into this.
Iron additives
These will help your plants keep in tip top condition; it is one of the most important additives. It should also keep red plants a bright red colour and is the only element which will need extra dosing.
ADA fertilizers
These just like any of the above fertilizers will work great, there is a point when we can expect minimal difference between each of the products, they all have the same thing but products like ADA provide the commercial trust.