I have a coralife 24 gpd unit. I need to replace the membrane, however I haven't found one that's rated at 24 gpd. Can I use a slightly larger membrane if I change the flow restrictor?
Yes. The Dow Filmtec 75 GPD is the same physical size and by far the most popular membrane available. I prefer Spectrapure's 90 GPD myself which starts out life as a Dow Filmtec 75 GPD then gets specially treated with a proprietary process proven to improve its performance then is either batch tested or individually hand tested for quality control unlike any other vendor offers. That and a matched flow restrictor would serve you well.