Based on the available info they both should be fine. No info on the makeup on the seals and I couldn't find them on a quick search of the Burkert site. I'd go for the 4w (first one) if you decide to take the plunge. Should run cooler.
Hard Hat by Day
Wet, Prunny, (hopefully)Green Thumb by Night
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Polygonum sp 'Sao Paulo'; Hemianthus glomeratus; Ludwigia repens; Starougyne repens 049 Tropica; Cabomba caroliniana; Limnophila aromatica; Heteranthera zosterifolia
Oto's; SAE's; Red Wag Platies: Gold Mickey Mouse Platies; Neon Tetras