What is the difference between Mahalaya Tarpan at home and at Gaya?

Mahalaya tarpan performed at home — in a basin or at a local pond — fulfills the basic obligation and ensures ancestors receive their annual water offering. However, tarpan performed at a Tirtha like Gaya multiplies the merit significantly. The Vishnu Purana places Gaya among the three supreme tirthas for ancestral rites alongside Prayag and Kashi. The Skanda Purana states that Mahalaya Shradh performed on the New Moon day satisfies ancestors as infinitely as the Devas enjoy nectar in heaven — and this merit is amplified at a Tirtha by the accumulated sanctity of the place. At Gaya specifically, the Agni Purana records that a single Pinda at Rudrapada or Gayasiras liberates hundreds of generations. At home, the merit is personal; at Gaya, it carries the power of the Gaya Asura boon granted by Lord Vishnu himself. If travel to Gaya is not possible, tarpan at Prayagraj Triveni Sangam is scripturally equivalent for water offerings.