Decreasing tank noise on HOB skimmers or other options

[Tropical Buff]

I currently have a 75gal with 2 bakpak HOB units, a dual and a standard that I house my heater and other filtration in. I am happy with the performance of the units, however I am getting sick of the gurgling (for lack of a better term) noise that they make. My main reason for not using a sump is my stand is divided in half and has minimal room to do so.

1st are there any fixes to reduce or eliminate this noise?
2nd are there any other HOB syle that are quieter?
3rd if a sump is most solid option how small can it be and still be effective?

Thanks in advance for everyones input

[AJ :)]

Perhaps you could cover the open side of the skimmers? I used to run a bakpak but don't recall it being noisy.

Maybe silencers for the air intakes?

[Tropical Buff]

I had consider modifying my canopy extend past the tank to go up and over the tops of the units hoever this would take quite a bit of work and I would want to be confident it would be effective.

My other concern would be the accessability to the collection cups. I have considered it though because I would like to raise my lighting some currently my PC light fixture sits directly on the tank if I extended the canopy it would allow more room for the lighting as well