correct on alot but not quite the direction im going for some.
I have a gap in back as the oxygen allows for flow.. As gas exchange between water and air in jar then pushes out through gap. Gap also serves to stop hose from being pinched. Circulation pumps I have found seem to generate alot of heat for this size. Even the small ones. The room its in can heat up due to computers so added heat from pump wouldnt be good. Plus the air hose gives it a cleaner look. Lid like you said also stops evaporation and puts the evaporated water back in tank. I might put airstone on to create finer bubbles to pop and act as skimmer but not ready for it yet. This is just a very low tech tank build for a virculation pump.
Im not worried about bristles and most hitch hikers. I want to keep most. I have just never seen this species and would rather pull if I decide to add snails or other critters to be safe. Snails I dont want to add as they produce more wast than crab or shrimp. Arrow crab will be to big. This isnt even a gallon. I also feed benepets which really doesnt foul up the water like other foods or powder.
Algae grows based off nutrients available. While live rock helps with biodiversity, it doesnt prevent or help with algae unless there is die off or something competing with nutrient intake. I do plan on adding a bit of macro algae eventually as well. I actually may remove the sand. I never have much luck and usually causes more issues. Had best success after removing in other builds. With 100 percent water changes weekly, things stay balanced and replenished nutrients with benepets for feeding. Want to avoid more rocks as it allows more detritus to build up and get cluttered. Finer sand definetly helps with fauna and stops wate from getting deep. But i stir up and create turbulance during water change so not something I am worried about.
The goal is to focus on this single sps. On the top of rock and have it fill out. Eventually it will out grow and I will put into a larger tank.
Gave me alot of ideas and directions to think about.
Heres 2 tanks i had. 5 gallon tank before married and moved as well as pitcher just around its prime before I was not able to take care of as well due to health. Wish I had my office tank pictures before we had to work from home due to covid. Similar to this build but smaller and was amazing. I would remove everything clean and scrub and put back on both these.