Bittrex -Take too much time buy bitcoin with altcoin Why ?

[topaccountseller]

Hello,  Why does Bittrex Take time to convert Currency Often Why ? I watched few times when i wanted to convert dogecoin into bitcoin And Ripple into bitcoin  , Convert time takes too much even days . But other hand When i going to buy coin using bitcoin its just matter of min
Whats wrong with Convert dogecoin into bitcoin, Ripple into bitcoin  in  Bittrex.com

Any can explain whats the reasons for happening this ?

Thank you in advance .

[alex-nn]

Use market order to buy/sell - not limit order!