Yeah, ever look down a well
Water tank maintenance per RV site:
Use 1/4 cup per 15 gal but add in small portions. Use a garden sprayer to add to the tank with some fresh water in it or pour it into the hose to fill from. Fill the tank but leave a little room to slosh around and drive around for a while. Make sure to run the shower and faucets. Drain the tank using the drain, shower and let some run into the sink. This will help clear the gray tank also. Add a ½ cup of baking soda in the sprayer and use the same procedure as before. Drain the tank then refill and drain again total of 3 times. Test water.
Here is what I usually do:
Drain the water system.
Remove the fill hose from my house connection and pour about 3 oz.
household bleach (Chlorox) into the hose.
Reconnect the hose and fill the tank.
Drive around to slosh the stuff around the tank.
Be sure to run some through every faucet (except for the purifier
faucet if you have one).
Drain the system and refill with plain water and a quarter cup of
baking soda dissolved in water.
Drive around again to slosh the baking soda water around the tank.
Flush the faucets.
Drain and refill with plain water. Flush all faucets again.
Refill the tank.
I do this about two or three times a year, depending on what's been
in the tank and how long. Only if the source water looks or smells
really cruddy would I filter it as I fill the tank. My water in my town is very
clean and not like some places I've been at. I add just a little bleach
to the tank so I can leave it in for a while. I don't
necessarily want to remove chlorene from the water in the tank,
because it will more likely go bad quicker.