Newbie here...need help / suggestions

I have robinhood account and mainly interested in day trading ..
but I found that robinhood web version does not have good charting software...i.e. it does not have indicators etc.

so I am wondering if I open an ameritrade thinkorswim account...can I use that account just for charting need and use robinhood account for actual trade?

(yes instead of paying 7$ per trade to ameritrade)

or can you suggest other options?