Hi,
Water pumps can be used to oxygenate the water. Also, I think they can be used with some undergravel filters. They are usually placed inside the tank.
As for the parts, Aqua Tech is manufactured by Marineland for Wal-Mart. So, you can email them for more information. I went to the site and didn't find anything current for the 170 GPH, only the 160 GPH. However, they may still have the information, both the manual and diagram of the parts, and possibly can email it to you.
I hope this helps.
Genaro