Suitable mesh layer to separate anaerobic bacteria deep sand bed (two different colours)?

[Robbie X]

Hello all.
I am planning on using the deep sand bed method on my upcoming Rainbow Snakehead project.
I have a load of kivu sand from a previous project that I will use for the base layer but I will be using black sand as the top layer.
I want to keep these layers separate, as the kivu sand has a lot of white and pale colours and I do not want them mixing.
Its purely for aesthetics and no other reason.
What would be the best material to separate the two without impacting the anaerobic bacteria process?
Cheers

 

[Mr.Shenanagins]

You could use landscaping material designed to keep weeds at bay. It will separate the sand but allow water to pass through

 

[Robbie X]

You could use landscaping material designed to keep weeds at bay. It will separate the sand but allow water to pass through

Many thanks 🙏🏼

 

[Kitalexander]

Cross-stitching mesh - Plastic Canvas 7 Count 34cm x 27cm