ugh So TOTALLY drain so bottom is dry????? Its really hard to get that last bit out. it will likely take about 2-3 days to do that, so by then test kit should be here. As for adding CYA, what product do I need to buy? I have liquid chlorine and muriatic acid.Sadly- as u can tell - the pool store results vary . The cya test is one of the ones they get wrong most of the time.
If it were me w/ a 6k gallon algae filled portable pool & an underpowered, undersized filter (& i have been in your position) - I would drain, scrub & refill knowing exactly what is in my water so I could enjoy my pool in short order. Only adding 30ppm of cya after refill & 5ppm of liquid chlorine daily until u can properly test.
Liquid chlorine is over $4 a gallon & it will likely take a lot of liquid chlorine & time to clear the swamp. Most slams take at least a week. Water is much cheaper in that respect.
When u receive your kit you can do things properly from the start & enjoy your pool in the meantime.