Perfect! 72 oz was correct! Any sort of vacuum is essential. But for right now at least brush, brush, brush. If your robot broke, and you don’t have another automatic way to keep the sediment stirred up, you need to brush. Give your pump and filter a chance to grab the stuff. If it’s very small particle algae, vacuuming to waste would be the best, especially if you can see what you’re wasting off the floor.
But for now, since your robot is broken, brush all you can. As often as you can. Keep adding your chlorine to keep that FC at least at 12ppm. I’d check that CYA again in the morning as if it goes up to 40 ppm, you’ll need to change your target FC to 16ppm, instead of 12ppm.
Keep it up! You’re doing great! I know it can seem daunting or like hard work, but if you can make it feel like a game with goals, then you can have fun with it. You e reached one goal already! 30 CYA! Not to mention holding some sort of CYA and keeping FC past 30 minutes (signaling you don’t have ammonia). Good job!
PS: You might take pics. Before and after. And even during. It’s fun to look back at before and afters. Fun to share with the forum too if you’re interested.