Yes you can, But I would prefer to use concrete mix the aggregate in the concrete mix makes it stronger
Yes just add water and mix.
It is good I like it 5 stars thank u don’t bother me.
yes you can, but will need to waterproof the inside of the fish pond with either a liner or masonry waterproofing also available at Home Depot.
Yes this is the product you would use. Spec mix grey or tan color. But first I would excavate to see how deep the existing concrete footing is deep 12" deep is good to add the additional weight of the new block course, also dowel holes into the concrete in the block cells are place #4 rebar and then build the wall, once built pour concrete into the block cells with the rebar you placed, place a block wall too cap and your done
Works just fine,done it that way myself
Depends on what you want to use it for? You can use it to skim coat the concrete planter but not to make one, spec mix is used for placing bricks or block and it can be used to skim coat like stucco or just get stucco mix also available at home Depot.