Load Previus Ivs Psychic Marina

[Y1n]

Hi, I was checking my bag and realized I have several RR Pokémon with reduced IVs.

 

Here's the question: how long does the previous 3 IVs on the Marine Psychic set last before they're removed?

 

I was planning to modify the Speed of some Legendaries with 31 Speed, and I'd like to be able to revert it in the future if I no longer need it.