Water wand not working

[Darkin2]

So i'm playing and i decide to make a underwater ocean base since I learned about the water wand (tropicraft) and it is supposed to remove water blocks. So i finish my base and try to use it, it takes away the water for a second then the water comes right back, the wand said it absorbed X blocks of water but nothing has changed. I keep using it anyway and it works, sort of, it takes away blocks in only certain places. It would be a great help if someone knew how to fix it or tell me how it works.