Ok, using borax, the pH is sticking between 7.2 and 7.4. I've been using bleach rather than trichlor and have been maintaining at about 5-7. (It's 30,000 gallons). Results from test kit run today: pH 7.3, Alk 140, free chlorine 5, combined chlorine 1, Cal 450, Cya 160 (1:2 dil with distilled water)

I know the Cya is very high. I did drain about 10-15% of the pool last week, but due to some unrelated plumbing issues I won't be able to drain more and refill for a few weeks. I'm finding it difficult to keep enough bleach on hand to keep the chlorine level up with such a high cya. Is it OK to use cal hypo to shock? Anything else I should be doing?