corals up high on rocks and water changes?

[Beemo]

i only have one coral now a green star polyp, but tomorrow i will be adding a yellow polyp, now for these 2 they will be on the top rocks about 2" from the surface. ive only been changing 10% of the water which only lowers it about an inch, but id like to change more, can the corals survive being exposed to air for about 15 minutes while i siphon and refill?
i see tanks with corals up high to the top too how do these people manage?

[tinyreef]

a short period of exposure shouldn't be too traumatic.

but if you truly worried then you might fill a container that's floating in the tank as you're siphoning out. that way the volumes are equal, i.e. no lowering of water level. and then you just tip it over slowly to re-introduce the new sw.

but frankly, i would be more worried about splashing/introducing freshly mixed sw en masse (pH & temp differentials) than the exposure (altho the exposure will introduce a significant amount of coral mucus). hth