Perhaps I'm missing something here.  Virtually any 15UF Cap will work as
long as it's working voltage (WVDC) is sufficient.  Say 35VDC.  The
electrical environment doesn't appear to call for a particular dielectric
material.  IIRC Tantalums are intended for small physical size, low voltage,
medium capacity.

RatShack carries axial and radial lead caps in 35WVDC and 22UF for less than
a buck.  272-1014 Axial 272-1026 Radial.

but hey, i don't use 20$ a gallon Cherman antifreeze manufactured by BASF.
I use the famous Wallyworld brand, also manufactured by BASF, $3.99/gal.
Phosphate Free,  tastes awful.

pensioner (buys costco gas, wallyworld A/F, RatShack components)

Hi sjohnson!