Hey folks! Something I've seen in a couple of aquariums but I haven't seen on any site yet, is the inclusion of a piece of celery. I've seen aquarists tie them to rocks and just drop them in. Is the celery for tank-inhabitants' diet? I can see the practical reasons for this for bottom dwellers, like shrimp. Would a large piece of celery have any effect on the water (PH, chemical levels)?