I am an aquarium hobbyist, so DO is something I am very familiar with. Many cannabis hobbyists fret like mad over it and very few of us are actually deficient until our reservoir temps get over 80°f. Chillers do help DO, cool water has more DO potential, but it really isn’t that hard to keep your DO up. I see a lot of giant noisy airpumps big enough to power bubblers for a whole fish store aerating a handful of buckets or tubs, people complaining about the noise, it’s so far past overkill that it makes me sad sometimes. One waterfall is just as effective, if not more so. That said, I do both airstones and waterfalls for redundancy. I use Tetra brand airpumps rated for 60-100 gallon aquariums, they are quiet.