Hey orlando I'm looking to order the Cal-Aqua filter piped from you soon and I am very confused about which size will fit my filter tubes. I have a Rena Filstar XP1 and I'm using the tubing that came with it. I've looked at the filter's box, website, and I've searched everywhere and I can't seem to find out what size it is. I posted it here because I though it might be able to help someone else. I'm also looking because I think it's time for new tubing, mine is looking pretty gross. Thanks.