Zinc or Aluminum in Philippine waters ??

[rhod2apuli]

Hello, i am new here, i would like to ask what's best to use in philippines waters
zinc or aluminum ??.. my previous was zinc and it is fairly good so how about aluminum ??... and by the way can i use both zinc and aluminum at the same time under my boat or not ??... and also it is difficult to find original anodes here in philippines but i already bought aluminum, please help, thank you

[celenoglu]

Galvanic voltage for zinc=1,25
Galvanic voltage for alu=0,75

This means zinc is more protective for anodic purposes. Iron is 0,65
This means alu cannot prtect iron but can protect brass and inox.
The votage difference is high enough to cause galvanic reaction among zinc and alu. Therefore do not use both of them at the same time.

[Fstbttms]

Anodes of either material are fine for saltwater environments. Mixing them probably not a good idea, however.

[rhod2apuli]

ok, thanks to you both fstbttms and celenoglu