Sea of blue my first grow

I’ve been dealing with fungus gnats. Sounds like a common problem I layer the ground with perlite and heavily put diatomaceous on top let it sit for two days vacuum the top layer off and repeat. Twice got all of them I can see and back to a regular feeding schedule daily. I have yellow fly traps I’m gonna put on the soil to help keep them down. I’m going to get a drip system. So there isn’t much saturated soil on the top for them to breed . To prevent this next grow