Fertilizers Needed For Plants?

Currently I have ApI Leaf Zone as this is the one I had always used for my plants ( java ferns ) but I am looking for a better fert (liquid as I have a sand base for my tank) that I will be able to use to with some amazon swords and anubis plants. And a new addition is a wisteria plant for my AFBF, but I think I also misundertand ferts for plants, as can these harm fish if to much is used within a few days or?

 

I believe Leaf Zone only contains potassium and iron. I like Seachem Flourish Comprehensive as a good liquid fert that has a bit of everything. If you just follow the dosage instructions on the bottle, you'll be fine. I dose once a week for my moderately planted tank and also have root tabs for my sword. I put new tabs in every 3 months.

 

root tabs are what excatly

 

Plant fertilizer tablets that you put in your substrate.
The roots of any plants planted in the substrate will get nutrients from them.

 

oh, are there any specific brands reccommended

 

I use Seachem root tabs but Osmocote plus tabs found on eBay are pretty popular as well (and cheaper).