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Were the filters disturbing your substrate or something? By the looks of it you should be ok, but I personally like to have a bit more surface agitation. As stated, don't worry unless you see fish "breathing heavily", seemingly gasping for air. If you notice anything like this, or anything else that seems odd, I'd throw the airstones back in or slacken the baffles a bit for more flow. Airstones are usually not necessary with HOB filters though(especially with such adequate filtration), and I think you should be fine.
Coastie-to-be... hopefully.