Clarification on "pool type" for my signature

Hi,
I was hoping to find the answer from searching threads and this site but alas, no luck. Just joined. Trying to do an accurate signature but can't see what to put down.
I'm in Aus, have a 40yr old concrete clunker,IG, nearly 60,000 litres.
It is apparently painted with vinyl paint-according to the 70 yr old lady who we bought it from 3 yrs ago.
I see that there are differences between ideal levels for different pool types.
What do I class mine as?
Plaster? Does the paint change anything?
I wanted to send a message to someone but see that it's preferred to do a new thread.
Can someone let me know please?
I have a ccl kit on the way and need to work on the right numbers.
Cheers