well my new tire (my 1st ever replacement attempt) lost psi slowly overnite again, it's at 20 this morning. It's a new standard sunlite, paid $7 at lbs. Maybe the slanted stem damaged the tube?

Here's my plan:
1. take out the tube, pump it, check for leaks
2. if no leak, will keep it out of the tire, pumped up, and let it sit overnite, then check the psi in the morning
3. if it holds pressure out of the tire, I will put it back in the tire again
4. if it has a leak around the stem, I'm tossing it

While testing that tube I'm going try a Bell cheap tube from walmart while

My other tire came that came new on the bike lost psi too overnite too- it's at 10 this morning!

How much pressure should a tire lose overnite?