Well not only tank cleaning but also the whole fuel system because the fuel not only touches the fuel tank on it journey from the station to the cylinder. Even if u clean the filter it wont be of any help. Plus your injectors will get damaged, probably will be already, due debris filled fuel.
And If you havent changed your tank before, keep in my mind that civic 2005 PKDM has a metal tank. If it's rusted, don't even think of getting it cleaned no matter what your mechanic say. The rust will return sooner than later. I'd recommend get the fuel tank replaced with the JDM tank which is of fiber glass / plastic.
Chinese metal tank will cost around 4k, whereas JDM fiberglass will cost you around 10k with its own fuel pump cux the JDM uses a slightly different pump assembly