dilute your test sample by mixing equal parts of pool water and distilled water and multiply the results by 2. If the test is still above 5, use 2 parts distilled and 1 part pool water and mutiply the result by 3 etc.

With 45 PPM CYA, I'd probably let the kids swim below 15 PPM Cl, but I'd have them wear their old faded suits until the Cl was below 10 PPM.