I work alone at minimum wage with tip jar. I put my tips into bag with all tips from pay period & are separated by hours you worked. I receive $20 tips on a shift. I don't get it. If tips werent good, I might not get $20 on my check. Is it legal? Ca

Your tips probably gets split with the people welcoming guests, the dishwashers, and the bartender if they ordered any drinks.

Legal yes .. But appropriate is questionable.  I never understood the theory behind the sharing of tips during a shift.  When someone tips, they ususally tip the servers which not only rewards them for their service but encourages good service. 

It is argued that tips should be shared between the cook and who ever happens to clean the tables, or even a cashier .. And maybe it's just me, but I happen to think that is not what the tip is intended for.  The cook (or chef, whichever the case may  be) .. Gets paid a good salary to do what he/she does .. Which is the primary reason people enter into the establishment in the first place .. For the food. 

I would far rather pay the tip to the server for their service, and the server keep it as it was intended. This is money typically collected by the server personally .. There is no reason it should pass through the hands of the employer .. or is your employer also taking a 'cut'?

You mentioned a pay period and you mentioned you worked alone, so in that case ... $20 for a two week pay period is obviously not enough. Do the math .. most customers would give at least a few dollars in tip .. over the course of 2 weeks, I'm sure you waited on more than  10 customers in TWO weeks. I would highly recommend you keep track of your tips if you are forced to put them in a jar for your employer to hand out to you keeping in mind .. if you employer is adding this to your pay check he/she is also calculating and deducting the appropriate income tax and employement taxes.