I have a 1986 oval tub in my master bathroom and I believe it’s acrylic. The only markings on it say Hytec A750. I’ve noticed hairline cracks on the bottom of the tub and in a few corners. I don’t see any evidence that the tub is leaking and I don’t know if I need to do anything about the cracks. Can you help me either contact Hytec or can you advise me on what to do about these cracks?