How can i clean my 500 litres tank?
 

Ok so my problem is how can i clean my 500 litres tank? it's so big and i don't want to make it dirty so what instruments and how should i clean it?
Thanks...

500 Liters of what? Water, oil, gas?
Is this a new tank?
Is it steel, plastic?
What does this tank do?
If you do not want it to get dirty then do not use it. The first time you do use it any soilds or hevey metals will always settle to the bottom so never had the outlet sitting right on the bottom. Install a drain so you can drain off the sludge.
Most tanks are cleaned with a high pressure steam pressure washer.

It's a water tank
No it's not new it's old one really old fashioned
this tank stores water which then goes to other parts of home

I got this type of tank here is the pic:
http://www.irrigationuk.com/images/u...mb_0200208.jpg

I want clean it, i know it's a minor problem but i just didn't want to mess with it that's why asking with what things (instruments) should i clean it.. i want this process to be easy, clean and less tiring..
Thanks

If you want it easy and simple then just go buy a new tank. If it's old then it's going to be rusted out anyway and will start leaking soon.
Do a Google search on pressure tank.

Well, i think you are right i should buy new one and i shouldn't get sticked up with old tank and yes i googled it with "Pressure Tank" and i found some really good tanks i think i am going to order one of them Thanks for the help Joe :)