Good Morfnoevight All! EO
Got an appointment with an ophthalmologist today.
You can get it tested but a house that old probably has lead paint and you want to get rid of it or seal it up. Chipping off like that can be dangerous for you and Duder! Look it up!
I doubt wood under that near the floor would be worth trying to expose, just way to much chance for staining.
If you can get Sothern AG Garden Friendly Fungicide it has a similar but stronger version of the microbes than Botanicare HydroGuard. I have never used it myself in my hydro but have used it outdoors. Others here have used it.