what to fill a nesting box with? red ear slider

[enz660]

i'm almost done with my nexting box/atba for my red ear slider and need to fill it with something. I understand some say a mix of sand and organic compost is good. What if some of the compost gets into the water? will it turn into parasites? will it poison my turtle? What if I used something else like dirt and sand?

Is there anything I can purchase at petco or petsmart that I could use in the nesting box? If so, please link!!

 

[snakeguy101]

I used a mixture of sand and peat. When I remove the eggs, I place them on vermiculite in an incubator.