little gaint 3-mdqx-sc pump is it worth it and will it work?

[ddc0715]

ok i have found a good deal on 2 used little gaint 3mdqxsc pumps. I have several questions.

Is this purchase worth it because they are used? Research says they are long lasting pumps

Where would be the proper place for each of them be?
In considering One As a return pump. i have about 7 feet of head height to deal with and it would be replacing a reef octo hy 7000 waterblaster pump that sticks when the power surges. the reef octo and these pumps appear about the same price if bought new.

or as a salt water mixing pump. to pump the new water into my tank. There would be about a 25 linar foot for the water to travel to my tank and about 8-9 feet of head (veritical) cause i would run the hard pipe thru my crawlspace then up to the tank.

Thanks in advance for the advice?

 

[shwareefer]

Used is no problem, they don't die. I have 2 5-md's that I've had for 30 years and they still crank perfectly. One of them looks like it lay on the bottom of the ocean for a while and it still runs like a champ. I now use the rusty one for my solar pool heater which is 400 feet of black pipe and a 5 foot head - no problem.