You also have to look at the quantity. We are not talking pipes here, just a single fitting. Most of the time that single fitting, even coroded, woudl not do any harm. Now if this were aquarium plumbing, well.........
125 Gallon AGA w/ Overflows
Filtration: Ehiem 2026 Filter, Dual "Ghetto" Overflow Internal Filters
Lighting: 1x96W Current USA CF - 2x96W Generic CF
Co2: Pressurized Co2 - Rex Grigg Regulator, SMS 122, and Rex Grigg Reactor.
Plants: Pogostemon yatabeanus, Foxtail, Bacopa, Egeria najas, Anubius, E. 'Ozelot Red', Ranalisma rostrata, Hornwort, Rotala Indica, Ludwigia Repens, Vals, Cabomba, Lilly, MoneyWort