That's the only issue with these old RE pumps, they're so silent that you don't know if they're dead unless you have it set on a current monitoring outlet.
That's cool, I've heard the same about units here being oversized but no manufacturers here having anything smaller. No smell off this unit? Injecting into your skimmer body?
If you only have 8 days then stay on Oahu rather than do inter-island. We frequently stay in Waikiki to avoid a car rental/parking since they're really expensive during the holidays. You can walk to Kaka'ako, Ala Moana, Diamond Head, the aquarium, etc. and see a lot of the island that way. We...
Reef Primer is the easiest to get, has simple instructions, and it's very gentle on corals. Neptune carries it. It's easier to see what gets knocked off than the pine oil based dips.
Interceptor is harder to get.
Did they get dropped ever? They're pretty fragile unfortunately. Also they often need to be broken in when first bought which isn't super clear in their instructions. Try swapping the wetsides too and see if the noise improves.
I've adjusted my lights to peak during my high solar hours and precool my house during that time as well on hot days. Also what temp are you keeping your tanks?
I know @Alexander1312 can attest too that in Europe they've shifted towards lower wattage pumps to save even more.
Just follow the Humblefish protocols to the letter. Don't modify. If you didn't meet the criteria of the 14 day method exactly, then run the 30d. https://humble.fish/community/threads/copper-treatment.17/