Water changes and appropriate timing to use water

[Shrimplady]

Hi guys,
I have 11 Bacterial tanks that are low. They are completely cycled and I added 50% extra water in a 30 gallon barrel. (15 gallons). A sponge filter and oyster shells filter this water. When would be an appropriate time to use this water and transfer it to new 2.5 gallon buckets with shrimp in them.


thanks!

Sam