Spahead007

Hello Fellow Spaheads, Newbie here, bought a 7x7 Artic Spa last August and using chlorine and have been having some water balance issues.I have read some of the posts here and have made some things clear,however my cyanuric level is about 100 I know this is bad and because it is that high I will probably have to drain and start over. Can anyone out there tell me how the cyanuric acid levels increase,what causes this to happen? Thank You in Advance