I'm not familier with that particular dosing pump, but I got mine on E-bay also. It was a used medical doser, probably the best purchase for my tank I ever made. Being a small 29g it is particularly important to make changes as undramatic as possible, and I can't think of a better way than to drip additives, such as kalk, or almost anything for that matter. I even used salt mix to drip and adjust my S.G. now and then, pure water lower S.G. or stay even, salt added raise it. As long as it's reliable you won't regret it.
