Step five: The siphon will draw up lesser gravel particles and sand that should still be helpful into the aquarium. Sift these through the dirty h2o, clear them, and replace them if the tank is cleaned adequately. Future, cleanse out the filter materials, introducing new bio sponges or filter substrate. https://hectorozhpc.gynoblog.com/36202230/detailed-notes-on-fish-tank-filters