Sorry about the pump..

Keeping the pH around 7 should avoid scale. Since your CYA is probably low, add bleach in the EVENING, at the rate of 1/4 gallon of Walmart pool bleach, or 1/2 gallon of Walmart PLAIN household bleach, daily. If you find your chlorine getting above 5 ppm in the evening, skip that day's dose IF your pool is algae-free.

Oh, and don't swim. Without a filter, the pool will get really gross, even with chlorine present.

But if the algae is under control AND you dose with chlorine daily, your water should be fine till you get the pump replaced . . . if you don't swim, and keep the big trash removed.

Good luck!