Terrible Advice Tuesdays: Granulated Ferric Oxide is just rust, so the scrapings from a rusty iron pipe will work just as well for phosphate removing media.
The rest of the story: No matter how small your saltwater tank budget, please don’t try to use rusty iron pipe scrapings in your tank. The rusty pipe could have all sorts of other chemicals in it that don’t need to be in your tank. Unless the pipe came out of your house, then you’ll have no idea what substances flowed through the pipe that might stuck in the rust and sludge in the pipe.
Add on the fact that rusty iron pipe isn’t exactly laying around in mass quantities. Finding enough rusty iron pipe to produce enough scrapings to fill your media reactor even once would take a lot of effort and time. Given the low cost of GFO and other phosphate removing media, just go buy some media meant for aquariums. The financial gain you might make is small and the potential risk of a containment getting into your tank isn’t worth the money saved.
(I’m going back to laughing about this one now)Browse the Store! Questions?