I removed this part:
(Japanese: 最大魔力; literally: Maximum magic power; Romaji: Saidai maryoku)
I'd be willing to let it back in if we can find out if there was an occasion when this phrase was actually used to denote bucket capacity and not just magic power/capacity in general. --Pip25 (talk) 15:05, April 21, 2017 (UTC)

Magic Capacity, from the Slayers Encyclopedia

I took that directly from the Encyclopedia, where it differentiates between 最大魔力 (saidai maryoku, maximum magic power) and 魔法の最大キャパシティ (mahou no saidai capacity, maximum magic capacity), from where the terms "spool" and "bucket" capacity where based. --shansito (talk) 23:40, April 27, 2017 (UTC)

Ah, that's good to know, thanks. I restored the previous edit. --Pip25 (talk) 12:48, April 30, 2017 (UTC)