OK. Your water has multiple problems. Your heater is at risk.

When was the last time you replaced your water?

And, you better post pH/ alk / calc test levels for your fill water -- presumably this is your tap water. Your tap water may not be much better; if so draining won't help much.

However, if your water is clear, I'd go ahead and swim. Just don't wear a swimsuit you are in love with. FC=40 at CYA=180 is not going to be a problem for most people. It may be a problem for fashion swimwear, and for colored or permed hair -- I'm not sure. FC=40 @ CYA=0 would definitely be a problem for swimwear and treated hair.

But dermatologists routinely put people, even babies, in "bleach baths" at FC=50-100@CYA=0.