If your Calcium Hardness (CH) were truly only 1000, then with a TA of 80, CYA of 70 and pH of 7.5 (and assuming 3000 ppm salt), your saturation index is only +0.14 which isn't high enough to produce the kind of scaling you are seeing. However, maybe your test strip is not able to measure super-high CH levels. However, you'd probably not see scaling unless your CH was closer to 2000 ppm or more. That would explain your situation.

Do you know the CH level of your fill water? Can you measure that separately and let us know? It would be better if you had a more accurate drop-based test for measuring the CH level especially since it is so high (i.e. a Taylor K-2006 test kit or Leslie's Chlorine FAS-DPD Service Test Kit or for just the CH test, the Taylor K-1770 here where you can use the 10 ml sample so each drop will be 25 ppm). As for what to do, that will depend on your fill water so let's get those results first.

Richard