WHat would happen if i did not wash the castings? I bought 2 pounds i was just going to put 3 cups in my new 20gallon. I plan on only dosing micro's to the water column. Substrate will be earthworm castings then eco-complete. plants will be Anubias nana Tennelus, and Rotala Sp. green. 55watts of light above it co2 injected.