The organisation had also run a number of mural art workshops, with new art springing up within the space all the time.
"Part of our role is improving the relationship between young people and the wider community. Our approach is strength based, rather than seeing young people as a problem."
Mr Thomas said graffiti vandalism was a difficult issue to manage.
"The old adage is 'just don't do that'," he said. "Really it's about giving young people the tools to actually understand why [they] shouldn't," he said.
"It's not only working with the contractors and police to enforce the law, but having the conversation with young people around how to do better. Open conversations are just another part of the puzzle."
Since 2013, the council had been collecting data from all organisations involved in the clean-up, including private contractors. Mr Thomas said it was promising to see rates trending downwards, despite a wider data pool.
Vandalism, including non-graffiti damage, still cost the council about $500,000 a year - equivalent to about 335 average residential rates bills. Much of the damage was caused by a small group of recidivists, with the etching of glass a particularly prolific and costly problem.
"There's a small group of offenders - both young and old - who cause the majority of the vandalism. Working with police we have made some inroads by targeting those prolific offenders," Mr Thomas said.
Lion's Den Ministries youth worker Ryan Anderson said tagging often stemmed from a need to fit in with a peer group and "make a mark". Youth Space had made progress in terms of giving young people that sense of belonging.
"It comes from identifying to a group, then expressing that round town [through tags] to make their presence known ... There's definitely been a decrease," he said.
