Could This Possibly Work?

[ZephyrStarPlaties]

I'm thinking about replacing the gravel in my tank for sand, but could I put some old gravel under the sand and make cycling not an issue? Keep in mind that I'd also have all the old filter media.

 

[Man of fish]

No
Cycling won't be an issue with all the old media. Plus the sand would go through the gravel making it a mixture.

 

[Cazgar]

If you're not changing the filter & it's fully cycled, then no need to add any old gravel

 

[CezzaXV]

Yup. The amount of bacteria held in the gravel will be little to none. No reason to keep the gravel.

 

[guppyguy84]

It won't work.