Good point. I've attached a photo below. I had read a few things saying that the agitators really aren't necessary, and I'm inclined to believe them, but part of me still wanted to have the option available. I'll go with swirling the tank and whacking it against the side of the bathtub to make sure the mixture gets sufficiently mixed/homogenized..

I bought it knowing it needed a few parts, which is fine. They where the cheaper option I'd found. I guess I still need about 2 reels to fit in the other tank - one expanded out to 120 width. So long as the reels fit the center column, I don't care what brand they are!
PatersonSystemTanksEbay.JPG

Actually, in looking at it, I think I might need just one reel? The perspective of the image is throwing me off - the eBay auction said one was a 3-reel and the other a 4, but I don't think that it is.. it looks more like a 1 and a 2-reel set to me?