The CoralBox (same as the IceCap V2) is reportedly a 24V, 4.4Ah, sealed lead acid battery. If so, it's crap and freakishly expensive for what it is.
Alternatively, you could spend $140 on this five-year warranty 20Ah EF River 2 direct from EF as a refurb. Connect that 12V port to a 12-24V boost converter (
https://a.co/d/hvTfaoJ), and you have a way better backup for 24V pumps that can do other things as well (like charge your phone or power your gas furnace).
https://www.ebay.com/itm/144819918766
The reefing hobby battery backup scene is full of sealed lead acid ripoffs.