Need help identifying my cartridge filter model #

[Zermus]

Ok so my cartridge filter needs a new air relief tube. The one I have is totally shredded. The cartridge filter I have has some Blue Haven branding on it saying 450 and 550 Series Smartfilter, when it's obviously just a Hayward filter. The Blue Haven sticker identifies the model number as either C4520BHMB or C5520BHMB. My pool is 18,600 gallons. I'm guessing the only way to identify is to pull out the cartridges and see what model they match up to? On top of that the cartridges I currently have I'm pretty sure are Unicel and not Hayward/Blue Haven, so I'm guessing I'll have to cross-reference?

Is there an easier way to tell without tearing down the filter to get the cartridge #s?

 

[Zermus]

Unicel C-7490 filters, 548 sq ft total, so I guess I have the "Blue Haven 550 Smartfilter"

Now I'm just wondering if that's the same as the Hayward Swimclear C5020 or C5025

 

[Zermus]

So my "Blue Haven 550 Smartfilter" is actually a Hayward Swimclear C5520 for anyone who comes across this.