This query does not strictly belong in this section, but I hope someone can help me:
I am working on a project for a boarding school in a developing country in the Pacific. I am trying to install a simple washboard type aerator above a tank (to try to reduce H2S smell). The water will be pumped into the aerator, flow through the aerator as through a waterfall, then enter the tank. I want to put a float valve in the tank to stop the pump when the tank is full. However the inflow will be into the aerator, which will be about 1.2m above the tank and will be a separate unit. I do not have any power available (the pump is about a km away so I cannot use its power source). Any suggestions you may have as to the float situation will be most gratefully received!!

What kind of volume of water is needed?

If it's low enough, you could do this on the cheap by using a typical toilet valve assembly. You could instal it either inside the main tank or is a small, secondary tank that is slaved to the level of the main tank. This type of toilet valve is often used as an auto-fill device for swimming pools. It will work fine as long as there is not a high demand for lots of water flow.

the old style high-tank toilets and urinals basically did this, and if you could find one as your destink tank, you'd have all the work done for you. they were new construction in the late 1800s through about the 20s or so.

Thanks for your thoughts.

The pump can supply about 6,000L of water per day (during daylight hours as we have a solar pump). The main water demand is in the morning and evening, but the tank fills up during the day (basically demand is everything that we can supply). The aerator will not have any water-holding capacity - it will fall through the aerator similar to falling over a waterfall. Attached is a VERY rough sketch of the intended set-up.