Help! Nematodes Prevention

[blng]

I'm having nematodes problem and I had to overhaul the tank. I have changed the soil, filter media and even discarded all the plants in my tank.

Does anyone know how did these nematodes get into the tank in the first place?

Appreciate any advice from experts on how to prevent a nematodes breakout again. I just started this shrimp hobby and I hate to stop it due to some worms.

Thanks

[Shrimplicity]

They usually occur due to overfeeding. If they bother you, you can make a trap using a plastic bottle and some bait

[blng]

Thanks for the advice

Would you have the steps to make that trap and what kind of bait should I use