Need Help With Scale In Spa

[partyboy]

I recently picked up a used 2005 Sunbelt spa for a price I couldn't pass up. It is some type of acrylic-not fiberglass. The previous owner didn't maintain the water well and I have a thick buildup of calcium scale at the water line. Before my last fill (today) I went at it with CLR and nothing happened. I tried 30% muriatic acid diluted 5:1 and that didn't seem to do much either. I gave up and refilled. I now have the time until my next fill to re-formulate my plan for the scale issue. Is it possible to remove this stuff or do i have to live with it? I tried the search function but it didn't yield much for me. Chemicals I have at my disposal: wet/dry acid, borax, TSP, bleach. Thanks in advance

Update: from my googling I am even more confused. So far I have heard suggestions of CLR, acid, vinegar, oven cleaner, and lemons. I will admit that I didn't read the bottle when I used the CLR and I simply used a nylon scrub sponge without allowing any soak time. My approach with the acid was the same. If anyone has successfully done this please let me know the chemical and method of application that worked for you.

Edited March 28, 2011 by partyboy