1. Algae is your fault, or at least, your responsibility. Getting a Taylor K2006 and reading the Best Guess page (linked in my blue signature box) will get you started on understanding that statement.

2. More urgently: a 2" per day leak is a serious, and probably hard to fix, problem. You need to act immediately, to preserve your legal rights. If you postpone till next spring you'll allow your builder to move things outside the typical 1 year warranty, and you'll be well and truly victimized. Do all these things, ASAP:
(a) your builder may not have deliberately, or even negligently, caused this problem. Do NOT presume that he did.
(b) BUT, do seriously and politely maintain that it is HIS problem, not yours, even if it is an unavoidable accident.
(c) TAKE GOOD PHOTOGRAPHS, NOW.
(d) Do the bucket test, 2x to verify ACTUAL leakage => http://www.poolforum.com/pf2/showthread.php?11252
(e) contact a lawyer, and have them evaluate your contract and legal situation. You NEED to know what you have to do, to avoid losing your rights.
(f) Do NOT accept epoxy as anything but a temporary patch. Repairing 2" per day leak on a new pool may be a VERY serious and expensive job.
(g) Get a K2006 ASAP. Correct and log your chemistry as quickly as possible. Questionable chemistry is commonly blamed for construction problems.

Good luck!