I hadn't thought about checking the dimensions either, but was pleased to see Seachem has published 17 dimensions for each of the Tidal models complete with illustrations:
Tidal 35: https://seachem.zendesk.com/hc/en-us/articles/360022289213-FAQ-What-are-the-dimensions-of-the-Tidal-35-
Tidal 55: https://seachem.zendesk.com/hc/en-us/articles/360022281153-FAQ-What-are-the-dimensions-of-the-Tidal-55-filter-
Tidal 75: https://seachem.zendesk.com/hc/en-us/articles/360022289533-FAQ-What-are-the-dimensions-of-the-Tidal-75-filter-
Tidal 110: https://seachem.zendesk.com/hc/en-us/articles/360022289693-FAQ-What-are-the-dimensions-of-the-Tidal-110-filter-