[wjuniorbr (OP)]

I have a tank with about 700 liters of water and about 400kg of epsom salt (sulfate magnesium), the tank is about 2.2m x 1,1m and only 25 cm of water in height. Im using a sand filter (like the swimming pool ones) to filter the water, I want to add a uv sterilizer to kill germs and bacterias that might still stay alive. First I thought about adding the sterilizer in the same pipeline of the pump that pumps the water to the sand filter, but then I ll be reducing the flow of water and thus forcing the pump. So I thought (and that is my doubt) to use a lid the tank with 3 or 4 15W uv tubular light bulbs under the lid close enough to the water, and turn it on while the water is being filtered by the sand filter so that the water will be circulating and all the water will get close enough to the light to kill the germs.
Will this work? The same? worse or better than the standard uv sterilizer?

Thanks for the help in advance

[Don_1]

What is your tank/water used for?

[wjuniorbr (OP)]

Its a flotation tank, its basically a tub where you float.

[evan_au]

Water strongly absorbs UV radiation, so you may need to pass the water through a shallow trough under the UV lamps, or install a stirrer to circulate all of the water up to the surface where it will be exposed to strong radiation. See the graph here.

Beware of a high humidity corroding your light fittings, and potentially causing an electrical leakage path through any dust on the light fittings.

[Bored chemist]

Pure water is actually reasonably transparent to UV- at least down to about 250nm
however, since this won't be anything like pure (especially after it has had people in it, you would be well advised to make sure the water gets pumped past a UV lamp.
The people who designed UV "filters" for ponds + such knew what they were doing.
I'd be tempted to use a second pump- even though the noise might not be a good thing.

[cheryl j]

If you don't want to build something you could look at what is commercially available for treating well water. I think there are UV filters for them. A lot of people in rural areas still have wells, since its not economical to run miles and miles of pipe to isolated houses and farms.