Just a note on that battery vacuum... I had/have one of those. I'm not sure what other people's experience with it is but I haven't used it in years.
The filter bag attaches to that little thingy sticking out just below center (where it narrows) and from center down must be under water level for it to work. When the vacuum is running, it creates quite the suction/blow out, the little bag puffs up and larger debris is very efficiently collected in the bag, and water is blown through and back into the tank. I found the bag (or any other I tried to adapt) did not collect minute particles (or else the suction process and whirling around in the bag breaks it down a lot, like a mixmaster) and in a very short time the water in the tank looks horrible. It does get filtered by your other filter and settles, of course, but there is no way you could do the whole tank in one shot and still see the fish.
Dabbler II, do you actually have one? How does it work for you?