When are Ferts Enough?

[theotheragentm]

So after all this reading about lowering lighting and making sure there are enough nutrients for the plants, I have a question. At what levels are the nutrients the plants use harmful to fish? Nitrates should be a given, but what about the rest of it? Following directions on Flourish bottles or dosing calculators, when do you end up killing off fish?

 

[rich311k]

I think you would have to pour in bottles of the ferts to kill fish with them.

 

[Purrbox]

You'll never overdose using the directions on the Flourish bottles. These are VERY conservative and geared towards a low light low maintenance aquarium. This also probably why they are so dilute. You really would have to significantly overdose before there's a risk to your fish unless you have some extremely sensitive fish, and even then it would take alot.