I found my venturi was loud as well during the break in but became near silent once the skimmer started to produce. I only ran it for a short time on a temp system as it now awaits the big system to boot up but I had no issues with it after break in.
Mag 18 on a 24 inch? Why? I would recommend the DCT-6000. It works well on mine and better than the mag 9.5. I don't like mags due to their inefficiency and excessive heating of the water.
The only thing I can think of is an obstruction of some sort. Maybe try flushing the air feed from the cup end with a few basters full of warm DI water? Another thing I'd try is to isolate the source by removing the airline at the venturi end ( does the noise come from the venturi or from the hose/coupling at the cup end?) and work from there.
Jeff uses a mag 18 on his 24. The bodies can handle more gph than the previously recommended submersible pumps.
I'm surprised some are loud though. dc9000 6/6 very quiet here still. I don't remember it even being loud during the short break in period.
I made a silencer from a pill bottle and it is a bit better also as others have stated it might be the turbulence. I hope that with time it quiets down.
I remember someone saying he used a Mag 12.
Anyone using the 24 on a 180 gallon Do you think its a good fit
Anyone using the 24 on a 180 gallon Do you think its a good fit
Anyone using the 24 on a 180 gallon Do you think its a good fit