Brown water while vacuuming - Possible filter problem

[imgamehere]

Have you cleaned the strainer basket lately?

[Manslick]

I’m not a sand guy but it seems to me that 25 year old sand may be ready to be replaced.

I have a DE filter and I have gotten debris out the jets too.

When that happens I back flush and recharge it with the proper amount of filter medium.

[madwil]

sand almost never needs replaced- other than after a Bacquacil conversion or similar where the filter is clogged.
The sand you replace in your filter is 1000's years old- the same chemicals that sanitize your pool will sanitize your sand!
Now, as far as the gunk returning to your pool- it's in the system somewhere, possibly in your sand; did you vacuum a lot of organics (leaves and such) through the filter?
if so, they should come back out during a backwash- just needs to be very thorough!
Is there sand coming out also? that would indicate a problem in the filter needing repair.
As far as the gurgling, you have an air leak somewhere- possibly the muliport, but more probably in the suction side as the multiport would not tend to cause the suction loss...
Check your pump strainer lid and gasket, and the piping between skimmers and pump... assuming you vacuum through your skimmer.

[jdolby]

try vacuum to waste to get all the heavy dirt out