Filter sock bypass confusion

[jestep]

I'm sort of toying with getting a larger sump on my main tank. I saw the super nice 48" sump that reburn had posted here, and I've seen this a number of times, but the drain lines don't go into the filter socks.

A few examples including the trigger systems one for sale:

I seem to be seeing these designs more frequently, but I can't figure out what the purpose of using filter socks is at all if you're not going to terminate drain lines into them. Some look like the sock is filtering in reverse, such as the bottom example, as in the water flows from the outside through the sock out the inside and then overflows into the next chamber, but many of these allow water to fully bypass the sock.

Am I completely missing something here? I can't see any benefit to allowing any bypass when using a sock or floss or any mechanical filtering mechanism because fluids will always take the path of least resistance which obviously isn't through a sock if there's a way around it...

[jolt]

I believe the back side of that sock chamber on the tideline sump is sealed, which forces water over the top of the socks. There are emergency drain slots higher than the sock spillway that would kick in if the socks get clogged

[AlexMorsePremium]

On the second two, the water flows down the main drainpipe, but it's capped, doesn't continue to the bottom. It flows back up and out into where the top of the socks are mounted. You can see it most clearly in the second one, with the large gap around the drainpipe.

Don't actually know why some sumps are designed this way, I'd guess to reduce splash and noise but haven't really looked into it.

[Juiceman]

Yeah, on the tideline, the chamber that pipes are going into is sealed, so the water flows back up and into the socks, only when the socks are clogged do they flow over to the right into the sump, thus making more splash which will indicated that they need to be cleaned.

[jestep]

Ok, this makes more sense now. I know I've seen them with opening lower in some sumps, not sure if that's intended to be something that can be closed. The reverse flow makes sense if it can be forced through there. I'm sure it makes cleaning socks a lot easier as well.

[Reburn]

Basically what everyone has said here. The plumbing goes into its own little chamber and flows back up to the socks. This allows you to run a full siphon drain since its submerged and reduce salt creep. Otherwise the plumbing would have to go in the middle of the sock and get low enough to get an inch underwater. It would make 7" sock removal a pain.