Quote Originally Posted by krifartida View Post
15XX system tanks have advantages and disadvantages compared to 25XX tanks.
the 250XX tanks uses less chemistry for smaller quantities of film per process, but get less efficient as you stack them up. the 1500 are better when loaded full or with extensions, but they do not allow for 4X5 reels...

also - i have found that even with a flat level processor the 1500 tanks as they are smaller are more prone to uneven developing on one end of the drum (usually the bottom end), where less active developer ends up due to the design of the tank, 2500 tanks suffer less from this issue.
(underlining is mine)

Doesn't the 25xx series use more chemicals than the 15xx series? My 1510 requires 140ml for 1 135/36 roll, and my 1520 requires 240ml for 2 135/36 rolls.

Regarding uneven development, could you explain better the part of the quote which I underlined? The bottom of the 15xx is almost flat, there is only a small niche which is filled by the base of the rod.