Switching gravel for sand/ mixing both

I bought a bag of play sand from some home depot place and I was wondering if theres a way I can put it into the tank without having to remove everything first?
If I just poured it over the gravel would the sand trap all the gunk which is in the gravel underneath?
Also what aquatic creatures are good at preventing dead spots.

Thanks

in my experence it is best to remove it all and then add the sand. just before you go adding it what sort of sand is it? sand isnt just sand! some sand is very carbonate rich which has the effect of increasing your pH. if you are using it for african rift lake chiclids then its perfect. if you are using it for bristlenose...disaster!

I use silica sand in my tanks becasue it is totally inert and will not affect the water in any way.

if you do plan on leaving the gravel in then you will need a lot of sand as the fish will quickly cause the sand to fall through the gaps in the gravel and it wont look as good. I would take the time and do it properly. took me about 3hrs when I switched from gravel to silica sand but it was well worth it!

Richgro play sand from Bunnings it doesn't say what sort of sand it is, I assumed it'd be safe because it says all that non toxic, children can eat it crap on the front.
Hmm gravels probably a lot easier seeing I can vac everything and it's less hassle.
Maybe I'll give it a miss until I've got a better sand strategy.

Thank you very much!

Maybe I can make sand castles

The Bunnings play sand is inert, i have it quite a few of my tanks.

You can vac sand, its just a different technique to gravel