Old sand substrate under new fluorite black

[Stef]

Want to pick your brains. I’m upgrading my 3rd and final 3 gal betta tank to a 10 gal. The 3 gal is planted with black sand (Imagitarium) and has been running for close to a year. The new 10 gal will have Seachem Flourite black. My thought was to use the old sand with good bacteria as the first layer and then add the new flourite on the top. Thinking this would ease new tank syndrome. Will the sand eventually creep upwards or interfere with the flourite’s benefits?  My plants do well in the other 10 gals on just the flourite. I also have a spare sponge filter running in another tank getting it ready for the new tank. Thoughts?

[Fish Folk]

On 6/19/2021 at 3:13 PM, Stef said:

Want to pick your brains. I’m upgrading my 3rd and final 3 gal betta tank to a 10 gal. The 3 gal is planted with black sand (Imagitarium) and has been running for close to a year. The new 10 gal will have Seachem Flourite black. My thought was to use the old sand with good bacteria as the first layer and then add the new flourite on the top. Thinking this would ease new tank syndrome. Will the sand eventually creep upwards or interfere with the flourite’s benefits?  My plants do well in the other 10 gals on just the flourite. I also have a spare sponge filter running in another tank getting it ready for the new tank. Thoughts?

My experience has been that sand generally stays on bottom, and larger substrate stays up top. Should work visually. 

[Samanthabea]

Not sure if it is true but my bagged live sand instructions say to mix new substrate slowly with old over a few days