Gruul Ponza is a Gruul (red-green) ramp deck with red threats like Boarding Party and Structural Distortion, so Blue Elemental Blast and Hydroblast can destroy key red permanents or counter red spells to disrupt their land destruction. Cut Abandon Attachments, Spell Pierce, and Plunder the Trollshaws since Spell Pierce's tax is trivial once they ramp past two extra lands and card selection matters less than answering their big threats like Annoyed Altisaur and Avenging Hunter. Keep Snuff Out and Counterspell as your main lines of interaction against their large green creatures.