The pH should be up at 8.2 and steady - big jumps in pH can really stress the fish out.
- What are you using as substrate (gravel/sand) - the best option is to use coral sand or aragnite to keep your pH @ 8.2
The filter could be a BIG factor. You mentioned you are worried that the fish might be sucked in. How big is the inlet of the filter?
- I definatley would reccomend having the filter on for a few reasons:
- Water Movement
- Oxygenation (could be the reason the fish are gasping)
- Removal of bad bacteria/detrius
(Someone correct me if I am wrong)