zozo
Member
I've used hydroponic fertiliser for my fish tank, it's much cheaper than anything for aquascape
GHE flora serie was the best and I used it to grow emmersed aquatic plants too
The difference in aquarium (suitable) fertilizer (if fish are added) and regular fertilizer for emersed growth is mainly the nitrogene source.
If we use dry salts we add for example KNO3, plants can take up NO3 readily from the water as food source.. Regular fertilizers can use NH4+ as nitrogine source from Ureum and Ammonium which is toxic for our lifestock in high concentration. For us this nitrogen source first needs to be biologicaly converted in the substrate or in our case also the filter into the less toxic N# molecule.
Not saying regular fertilizers are absolutely unsuitable for aquarium with lifestock but you are definitively at risk and on the edge of killing things if it accumulates into toxic levels. Depending on your stocking levels a tank produces already it's own share of ammonium, than adding extra is not always a good idea without controling very closely what you are doing and knowing what and how much you are excactly adding.