The filters on these things don't have a skimmer--they use a little cartridge that you can wash or replace for about $10.

"McGyver" can certainly rig up a vacuum--I did it by forcing a double-female 3/4" PVC fitting halfway in one end of 18' or 1.25" hose. The other end fit in the Intex drain fitting (to the pump--it's called a drain) perfectly. It sucked up the fine stuff. But BOY, a PoolBuster is easier and works better!

Lots of people use wet/dry shop vacs in little pools. Work fast! You can start a syphon too, and vacuum with that (like in a fish tank). No energy used but you have to replace water.

If the kit is the HtH 5-way test kit it may be OK. If it's old, no matter what it is, the chems must be replaced. But the better kits that I listed give you a much more accurate, precise and extensive look at your water to catch issues before they become problems. You only need to run ALL the tests once a week, but chlorine and pH should be tested every day.

It's simply worth it to have a good test kit and use it. It will pay for itself many times over. All three kits use Taylor chemicals and they are easily replaceable if and when you run out or they get old.

For adding CYA, you can either use a floater with a puck in it (that will add chlorine too) or use that GREAT trick of an empty floater, a stocking and hanging the CYA in it!