Is this diatoms?

[TJ6404]

Is this diatoms and if so what would be the best cuc for my biocube 14 thank you!

 

[Formulator]

Yes. Judging by the photo this is a new tank and diatoms are more or less inevitable. Don’t worry too much about it. They will go away as your tank matures, but they will probably get worse before they get better. Just a normal part of beginning a tank. Best clean-up crew for sand IMO are fighting conch and nassarius snails. Hermit crabs are great too, but some people don’t like them. Whatever you do, don’t buy any fix-in-a-bottle products as they so often do more harm than good in new tanks.