Properly grown flytraps should not be growing right now since it's Winter. Your mix is fine.

They don't grow much when dormant. If your sand contains any minerals that could be part of the problem. Just because it's been washed doesn't mean it's without minerals. Silica sand is best. Peat/sand is close to what they grow in naturally but peat/perlite works good also. I wouldn't say either is better.

well i couldn't get mine to go into dormancy this year(mine were kinda in the middle of their growing season when i tried to get them to go into dormancy so next dormancy period i will try again)my sand is just washed playground sand i bought at home depot.

If (as you said in your first post) they aren't growing very much, then they are at least semi-dormant. They don't necessarily have to die-back to be in a state of dormancy.

I use playground sand frequently and it has worked fine for me. If you want to be sure, get a TDS meter, measure some water, add some of the sand, and take another reading. If it goes up a lot, then it needs to be washed more.

what is a TDS?

Total Dissolved Solids. Google it.