Here is what I do once a year to Raven Dancers water tank.
Attach a length of plastic tube over the end of your faucet, pitch the other end out the window about 6' ~ 8' of tubing is fine.
Now give a couple of pumps on the foot pump and the water from the tank will start to sipion out on its own. Leave the tube attached to the faucet you will need it again the next day.
Once the water from the tank is empty mix one cup of household bleach for every 10 gallons of water. If your tank is like the one in my 2006 it is a 20 gallon water tank, so with my highly developed math skills you will need 2 cups of bleach.
I mix the bleach in a quart pitcher with water to make it easy to pour into the water intake on the boat, without spilling it all over.
Once you get the "mix" inside the water tank, becareful not to slop this water on your new jeans or shirt, unless you like tiedye stuff.
Now refill the water tank with plain water using the proper type of hose of course.
Fill the tank so the water goes well into and up the indicator tube on the boat. I then get an eye dropper and add a few extra drops of bleach down the end of the tube.
Now go to bed and let the bleach mixture soak overnight.
The next day you are ready to drain the bleach mixture from the tank, so your tube is still attached to the end of your faucet so give the foot pump a few pumps and get the water flowing and drain out the tank. I rinse the tank out twice with clear plain water.
After the final rinse and tank refill I get a glass and fill it up with water from the boat tank and hold the glass up to a light or the sun if you live outside of Washington or Oregon. You should see nothing but sparkly clear water, if you see "floaters", or other debris I would repeat the entire process with the bleach mixture until the water is clear.
I know that this is a time consuming project, but you can take solic in the fact that messing about in boats does not deduct time from your life span ! So enjoy the project.
Big Dave.
Raven Dancer.