What fungicide can I safely use on my tomatoes

We are running a aquaponics system in our high school and our tomato plants have started getting black spot blight. I am wondering how to treat it… I am not sure what fungicide I can safely use.

That’s always a hard one when your crops get infected. Blight remedies are normally remove all affected plants and burn it so you can kill all the spores from the fungus.

Probably Alternaria,

There is a treatment possible with nettle or horsetail tinture.
You could try it.

In most cases, when a plant starts to get infected by pests, there are deficiency in nutrients.