I don't know what all purpose is, but the sand/portland mix is easier to work with than concrete with 3/4" aggregate because of the smaller aggregate size.

 

first off it has Lime in it bad for shower pan second to make a shower pan you use 1 part Portland cement to four parts clean sand or the sand mix. you make to a humid consistancey just to were you can form a ball. using any thing else is not a good idea.

 

Do not use concrete mix for a shower pan----the fluid nature of the material leads to settling as the material sets---changing the pitch and causeing puddling---

Use deck mud like Nailbags suggested.

 

The contractor I used to work for used quikrete all purpose for probably 30 yrs without one failure. I personally have done close to 50 showers this way. I'm always open to trying new things . This is just what I was taught. My old boss said the all purpose with the bigger aggregate is more structural . It has sand , Portland , sand, and small rock/stone. All I know is it makes a damn solid pan and curb.

 

Regular portland cement, sand, and water. If you can't scratch the surface after set time then its mixed wrong.