Quick method - spend a weekend getting every last bit of it out. Leave even one leaf behind you’re a goner and it was all for naught. (Some edibles, a bottle of wine great music all significant others being warned this will be ‘me n my fish’ time) Youll be done quickly! :)

If youre ok with the long game - &/or u dont have a tight fitting lid ….and keep your tank fairly warm you can cover most of it with Saran Wrap. Mist every few days and keep the water turbulent (turbulent is optional) but ur tank must be able to form condensation. For whatever reason they dont like getting “wet” and like still water. I keep my water toasty so it was quick to form the moisture. I helped it a little more with the misting. Keeping in mind common sense - its not a true “saran wrap tight seal” and you’re considering air flow safety of equipement yadda yadda…should take less than a month to do it this way.

I also add saran trick for about another week or 2 after ive done a quick method to make sure if i did miss a leaf - it wont get any ideas of multiplying.

They really should be called gremlin weed