Any good fungicide for seedlings?

[NYCorchidman]

I have read how some members did well with seedlings without the help of any spray, but I need some good spray. I'm an indoor grower, so nothing too strong like commercial grade.

My paph seedlings are losing battle to brown rots.
The larger ones are doing fine, but the smallest of the group are all about to go.

I would like to have a good fungicide handy so I will spray my seedlings in the future trials.

Tell me what you use and how efficient the result is.

Thanks!