Let me describe the sanctum of Sri Kalyana Bagavathi
Lord Sivayoga Subramaniar
The next idol installed at the peetam was Lord Murugan known as Sri Sivayoga Subramaniar. Once during Devi pooja, Devi ordered Swami to construct a separate sanctum for Lord Murugan. When Swami enquired about the idol, she told him that she would tell the whereabouts of the idol later. After a few months, she ordered Swami to carry two fully ripe coconuts and proceed to Rameswaram. She also ordered him to go deep into the ocean in a boat bearing number 17 and throw the coconuts east and west in the calm water. She said the two coconuts would meet at a point and wanted him to jump into the water at that location where he would find the idol of Lord Murugan. As per the divine direction, Swami proceeded to Rameswaram. At the seashore, he searched for the boat having number 17. No boat with that number was to be seen. He was in a fix. He called siddhar peetam from a nearby phone booth and enquired about the sannadhi construction for Lord Muruga. The telephone bill number was 17. He immediately concluded that definitely a boat bearing No. 17 should be there. When he returned to the sea front, he saw a boat returning from deep sea bearing the number 17. He requested the boatman to take him in his boat into deep sea. The boatman refused saying he was very tired since he had just returned after a long day of hectic work. Moreover he said that due to terrorist trouble, the government of India had imposed certain right-of-way restrictions and that they were not supposed to carry passengers after a certain time, in anticipation of trouble. He tied his boat and was about to leave when he noticed that the boat had become untethered. The ferryman first thought that he might not have tied the boat securely and so he secured the boat with care and again, to his surprise and shock, the boat untethered. The boatman was now scared and perturbed by the mysterious happenings and approached Swami. He requested Swami to get into the boat and they sailed into mid ocean. At one point, the motor of the boat stopped automatically and would not restart inspite of repeated efforts by the boatman. As the boatman was busy with the boat engine, Swami heard the Guru's divine voice asking him to throw the two coconuts as directed. Within few moments, the two coconuts got together at one point and Swami jumped into the water that was more than 300 feet deep. Seeing Swami jump into the water, the boatman was terrified. Within a few moments he saw Swami coming out of water with a sack. The idol was inside the bag. Having got into the boat, Swami offered to try and start the boat and lo! It started, much to the astonishment of the boatman who was struggling to get it going. The boatman was reverently curious of the events and asked Swami what was in the backsack. Swami evaded the question and suggested that the boat be taken back to shore. Swami offered charges for the services of the boatman and enquired if he owned the boat. The boatman said that the boat was purchased with government loan and since he had been unable to repay the loan installments, the government might be taking it back from him at any time. Swami consoled him and said that within a week he will own the boat. (To his pleasant surprise and delight, the boatman got a waiver of the future installments within a few days and came to own the boat.) Swami returned to the peetam with the idol of Lord Murugan. Much before Murugan arrived at the peetam, a person who was not a devotee of Swami had already delivered the kavacham, on the basis of an intuition he had experienced. The idol was installed and the Kavacham fitted the idol perfectly. Everyone gathered were wonderstruck at the miraculous happenings. A few days later, Swami received a letter from the boatman saying that his loan had been waived by the government and that he now owned the boat. He expressed his desire to meet Swami again and get his blessings.
Swami while returning to peetam asked Gnananandar about the whole episode of Lord Muruga. Gurunathar explained to Swami the historical legend of the Lord Murugan idol recovered from the deep sea in Rameswaram.
About 300 years back there lived one Nadar in Tuticorin, a southern town in Tamil Nadu. He was a businessman and was carrying on business with Ceylon — presently Sri Lanka. He wanted to construct a Murugan temple at his place of business. He was an ardent follower of Sri Pamban Swami and with his blessings, he got the idol of Lord Murugan to be installed in Ceylon. When he was sailing back with merchandise and the idol of Lord Murugan, a severe hurricane developed in the sea and the ship was about to sink. Everyone on the ship panicked and feared the worst. Sri Nadar started praying to Lord Murugan to save all of them including the idol from calamity. Suddenly, he heard a divine voice telling him that a temple already existed for Him (Murugan) in Kadhirkamam (seven hundred years back Tambaram was known by that name). Hence He (Lord Murugan) did not want another temple in Ceylon and wanted Nadar to drop the idol in the sea right away and by doing so, everyone on the ship would be saved from the mishap. Nadar implicitly obeyed the directions and thus saved all aboard the ship from grave calamity and they reached Ceylon safely without any further trouble.
Until Swami brought the idol up from the sea, the idol was lying in the sea near Rameswaram. A large number of devotees gathered to witness the sacred installation. They were spellbound by the mysterious powers of the Lord. During the pratishta there was another miracle. A stranger who was a staunch devotee of Lord Muruga living in Crompet near Tambaram had a dream the previous day. Lord Murugan appeared in his dream and told him to compose a song on him and sing it during the prathishta the next day. He also told him how Swami had acquired the idol. So at the appropriate time he sang the Sivayoga Subramanian kavacham, which depicts the entire story behind the origin of the idol up unto the pratishta in Tambaram. Everyone present was wonderstruck and in awe of the significance of the event they were witnessing. Abhishekam was done to the Lord with milk, honey, curd, panchamritham, sandalwood paste and sacred ash. A homam was done and the divine verses singing the glory of Lord Murugan echoed everywhere. Swami felt that though the idol came from Sri Pamban Swami, it was Gnananandar who actually created the idol and that was why he knew all about it.
A divine kundam (pit for homam) of Lord Murugan shaped like a hexagon was dug six feet deep in front of the sanctum. Lord Murugan is called by six different names and has six different divine abodes. Anyone who would sit at that spot and meditate on any one of the names of Lord Muruga would be cured even of incurable diseases. Thus Sivayoga Subramaniar acts like a divine doctor. An unbelievable and miraculous incident occurred recently, a couple of years ago that serves to reveal the sanctity of the Lord. An ailing patient came to Swami suffering from advanced stages of cancer. He had been treated by various specialists and all had given up hope. He fell at Swami's feet and asked for his divine grace. Swami told him to sit in the particular spot in front of Lord Murugan and pray. After a few days the patient was completely cured and now leads a normal life. No words can describe such divine grace!