Honestly I wouldnt mess with k1 cause it becomes a pain. But if you want the extra noise, and upkeep of k1, I ran roughly a turn over rate of 2x the volume of media. So if its 1 liter of media you would need 2 L /min per liter of media. When you have a lot more media (+30 liters of media) you can get away with less air per liter of media as the media will become a big mass and move. In part of a 75 gallon sump (the middle) I had about 50-60 liters of media roughly 15 gallons of k1 and had a 70 L/min pump and it worked pretty well. In theory tho, you can pump as much air in it as you want and itll still work fine and it will actually help keep the media clean.
Good thing was its only 60w's for 70 L/min but its so damn loud and the evaporation is insane. You'll be topping off the tank every 3-4 days, and you'll be surprised to see how much dead bio or beneficial bacteria they produce which needs to be cleaned out every 2 weeks to a month. In the beginning itll seem like too much air and once it ages and becomes less buoyant it'll seem like you need more air. Its a hard system to maintain for not much reward.
Some ceramic media achieves similar results, I always wanted to try the pondguru's ceramic media as he claims the middle is so dense denitrification bacteria thrive there and will consume a noticeable amount of nitrates.