1) In a quest early on the quest was to explore the pool room in night modus for 5 times
TIP: exploration of ANY room in night modus does the trick here
2) Later on there is a quest to explore the pool room with Storm- phenomena (5 times) and banish with the 'Leaf-blower'
Earlier you have gathered the summon items to summon the storm and the banish items, here is the way to do it without using duckies to explore it (because those Donalds are very scarce!);
TIP: First get some phenomena in the other rooms in the basement (garage, cuddy and gym). Then get the first Storm in the pool and banisch it with the 'leaf- blower' After that repeat this actions 5 times.
3) After this you should explore the pool in Night modus 3 times.
TIP: if you dont have the night modus in the pool (or any other room), get a phenomena in the room (for example Mist or Will-O-Wisp or Native Idol) and Banish it (so it won't count for an exploration and the percentage doesnt go up). The modus is then different. Do this until the modus is Night and Explore the pool. This way you 'only' need 60 duckies to explore the pool 3 times in this specific mode.
Good luck and let me know when it worked for you!