Diesel in my camper water tank

So.... not exactly the smartest thing I ever did, but I bought a new camper this weekend. First fill up was in the rain, late at night, in the dark. I reached for the diesel pump, opened up the fuel cap with the key and popped in 25 litres of diesel. Only when I hopped back in and noticed that the fuel gauge had gone nowhere did the full horror hit home. Now, I have fuel tank and pipe system which has had diesel in it. The water will is used for showering and washing dishes etc.

I have removed the water tank from the camper, and the tubing, but I need to be able to really clean the tank and get rid of the diesel, and the smell.

Any ideas. I have tried Soda which does some of the trick but not at all what is needed.

I know it was a stupid thing but.......anyone?

Simon

Diesel is oil (petroleum) based.
Soda (Sodium Hydroxide??) may well help, but it will take time.
Because the SMALL amount of Diesel will adhere to the walls of the tank, it WILL need to be removed. Smells unpleasant. Doesn't need more than a little bit.

SOAP, Kitchen detergent, will disperse the Diesel.
And then MUCH dilution with WATER, will dispose of the Soap/diesel mix.
Good luck.

As usual, I presume someone in trouble can think clearly. WRONG.
So I will be more helpful.
1/ Drain Water/Diesel mixture from Tank within vehicle.

2/ DRAIN as well as possible. The more of the diesel which drains out, the less will be needed to be dispersed with Soap/Detergent.

3/ Refill Water tank with Water and DILUTE Soap/Detergent mixture. BECAUSE there is only a wall amount of diesel left in the tank, we do NOT need an enormous amount of soap to disperse.

4/ Drive around for a while. Let TIME and Vehicle Vibrations do the job. Say, a couple of days.

5/ DRAIN as well as possible. Repeat from STEP2. Should take no more than 5 dilutions. Cheap, simple. WILL WORK. Good luck