Plz help my research sponge filters

[TealStarlight]

I googled dangers and risks of sponge filters but im still confused by this i read on the aquarium coop site. For the circled in red in photo attached, what does it mean fine sponge filters if floating cause lack of oxygen and loss of life?  Like the bubbles will stop? I got 2 5 inch width sponge filters for a 75 gal aquarium with one full grown comet goldfish but they sink fine after soaking in a 5 gal bucket. Its been only 8 hours of soaking but is there a risk they might float still? 

[macdaddy36]

If you ordered the filters from aquarium co-op this won't be an issue.

If your sponge filters have a weighted base or they feel heavy in your hand this won't be an issue.

One you have them at the bottom they will be fine.

[madmark285]

On 4/9/2024 at 6:45 PM, TealStarlight said:

fine sponge filters if floating cause lack of oxygen

Possible mean, gas exchange occurs on the water surface. A large sponge filter floating will reduce the surface area thus reducing gas exchange. Gotta give them a D for that one, no explanation? 

[JMC]

I also make sure to squeeze the air out of my cheap off brand sponge filters when I place them in the aquarium. With the sponge filter’s weighted base they’ll sink without being squeezed but it seems like a sponge filter should be full of water so I want to get the air out. Squeezing the air out of them also obviously makes them less buoyant.