If the algae is gone by then and you're just going to be gone a week, you could just leave your pool at shock level (25 ppm) and then have your father-in-law come over on the third or fourth day and add three or four 4 gallons of bleach. Three gallons will increase your chlorine by about 6 ppm and four gallons will increase it by about 8 ppm. Even if the pool uses 3 ppm per day, you'll return to a pool with at least 10 or 12 ppm which is adequate for your level of CYA.