Apt complete is relatively Low in no3.
Apt zero does not contain no3. People seem to quite like apt products, no first hand experience however.
Tropica premium does not have nitrogen or phosphorus. I have had good results With tropica fertilisers.
Consider making your own fertiliser perhaps? I buy my dry salts here;
Hello everyone, Based on its ancestor, the new IFC Aquarium Fertilizer Calculator is completed at last. This has been a long (sometimes fun, sometimes painful) adventure for me. I have spend more time than I care to admit but here it is, ready to roll. Home screenshot here below: Background...
I was approached by @swyftfeet for some help with the IFC calculator. The calculator is not really intended for the newest newbies, but if you know what you have in mind for a fertilizer, or have been told by someone what you need, you may be able to get by :thumbup: This little tutorial aims to...
Just a note for your info, about local peculiarities: In my country, commercial fertilizer blends make a relatively poor turnover. Most hobbyists, esp. experienced ones, use dry salts and prepare their own stock solutions. It's cheaper and you can readily adjust dosing of selected nutrients according to development in the tank.
Sadly, only few - me included - go as far as to make individual solutions for micronutrients.
A very good question, indeed. If I were asked, my reply would be following:
(-1) The toxicity of nitrates is very mild, yet scientists discovered that even plants with good resistance to eutrophy (Vallisneria sp.) activate certain enzymes and produce certain compounds which are considered unmistakable signs of stress when nitrate content is elevated (roughly 5-10 mg/L). Admittedly, it has little practical significance in our hobby.
(0) Plants take up nitrates not only for assimilation but also in order to maintain ionic balance and osmotic pressure of their fluids. If nitrates are in short supply (which is natural), plants take up chlorides in their stead. Chlorides have been proven to provide certain protection against parasites, namely fungi. Again, this is of limited importance in our hobby, as far as I (we?) know.
(1) In sparsely mineralized ('very soft', below 50 µS/cm) water, elevated nitrates can easily lead to deficiency symptoms of other macronutrients.
(2) If nitrates are abundant, the suboxic zone (where microbes respire nitrate - denitrification zone) in the substrate is thick and may reach the very bottom of the tank. If this is the case, the zone where iron is reduced may be completely missing. This is important because iron, phosphorus, and other transition metals remain in their oxidized state, i.e. precipitated and buried useless in the substrate eternally. I believe this partially explains why those who lavishly fertilize with nitrates have to dose incredible amounts of phosphates and especially (chelated) transition metals.