As mentioned on another thread, the “zincs” for Side Power are actually aluminum. They have standardized on this exclusively. Apparently Side Power has determined that it is ok to employ their aluminum anodes on boats that have actual zinc elsewhere. I had previously understood that aluminum should not be mixed with zinc even if there is no electrical pathway through the boat, since the water itself can form a conductor when dissimilar metals are in close proximity. But I assume Side Power has done their due diligence in standardizing on this.