David and Donna Rankin paid tribute to their "beautiful girl", who they will always miss.

They made their comments shortly after the coroner delivered his findings that the spa had been dangerous since its construction.

"She was beautiful inside and out," Mrs Rankin said.

"She was funny, she had a quirky sense of humour, really kind and gentle and had quite a wise old soul."

The Rankin family has appealed for a comprehensive overhaul of how pool and spa safety is regulated and enacted across Australia, including annual inspections of private and public pools and spas.

Earlier today, Coroner Paul MacMahon found the spa that Shannon drowned in at a Forster apartment complex in 2006 was inherently dangerous from the moment it was constructed.

The girl became trapped on the bottom of the spa after duck-diving at the Sevan Apartments.

The coroner found she became stuck to the cover of the main drain of apartment complex's spa pool, which exerted a suction force of up to 350 kilograms.

Mr MacMahon found today that the danger existed from the time the spa was built because of a blockage in the main drain, however the danger increased shortly before Shannon used it, due to a filter becoming operational.

Mr McMahon said the drain had become blocked during its installation due to layers of material getting inside, including soft, reconstituted cement slurry, solid cement and a mixture of pebble-crete, cement, sand and dirt.