# Sand or gravel



## Gregory Day (2 May 2019)

which is best cap to use on a dirtied substrate sand or fine gravel. I have both


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## Tim Harrison (2 May 2019)

Anything with a grain size of around 2mm to 3mm is good. But if you're water column fertz dosing as well, just go with whatever you like best.


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## Aqua sobriquet (2 May 2019)

Fish like Corydoras appreciate fine sand so bear that in mind.


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## alto (7 May 2019)

Aqua sobriquet said:


> Fish like Corydoras appreciate fine sand so bear that in mind.


Mine obviously forgot to read The Memo 
- completely ignoring their specially designed and installed sand zone in favour of sifting through the Tropica Aquarium Soil Powder

In answer to the OP, I’d (still) create some finer sand areas for the Corydoras


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