The Victorian structure was emptied on 13 January for its annual maintenance.
Guernsey Harbour technical services manager Martyn Stanfield said it had gone really well.
'They were clearing out silt and rubbish and finding things like broken glass.'
Then Technical Services staff went in to make repairs.
Mr Stanfield said it was not easy to find the cracks and they would know if they had repaired them all only once the pond was refilled.
