How to make an item transform in the water after some time?

I want to make the item change after being in the water for, say, a few seconds, while playing a sound. I found a tutorial on how to transform an item in water instantly, but when I try to add a delay, something goes wrong. After the item falls into the water, the sound is played during the delay, the item disappears, but in its place appears 100 other objects, not 1. I realized that this is due to the delay time, because if I set a wait of 99 ticks, then 99 objects will appear.

Please help me, how can I fix this?