Is this basil blight?

[vestigo]

I am new to planting basil this year. I have 4 plants in 6" pots with a soil-less mix. I moved these pots outside on a small table, and then suddenly after about 3 weeks outside, the leaves started turning brown, starting with the lower leaves. So, I clipped all the ones and brought the plants back into my patio where they get partial light thru the screen. Now, all the other leaves are starting to get the same brown in the top, and a moldy looking splotches underneath (as shown in the pictures).

Do my plants have this "basil blight" that I've read about? Or does this look like something different? I've looked, and don't see any bugs on my plants, but there are sometimes a few gnats in the mix.

I use the same soil-less mix that I use for all my veggies. It drains well, and I only water when it feels dry an inch or so in... the plants look healthy other than the brown leaves...

Any knowledge is appreciated. I want to make sure that I don't ruin my next batch of basil plants with whatever I could have done to cause this.

Thanks!