each 60 oz borax raises 1000 gallons 50 ppm and requieres 30 oz of acid. Each box of 20 mule team is 76 oz. I am going to assume 7000 gal of water which sould be fine so your friend would need 26 1/4 lbs borax (about 5 1/2 boxes) and 1 1/2 gallon and about 1 pint of acid. The acid should be fine in an intext pool. Put in half the borax (presdissolved), then 3/4 gallon of acid (3 quarts)--you might want to add it a quart at a time by putting each quart into a 5 gal bucket of water first and then broadcasting it into the pool, always add the acid to water--NOT the other way around), brush the pool well to mix it up. Then add the rest of the borax and the other 3 quarts of acid and brush and let it circulate for about 24 hours. Test the pH and bring it back down to 7.6 with the rest of the acid. You might need an ounce or so more to get to 7.6 over the pint.