Cleaning diesel tanks

[Falcoron]

having just bought new diesel tank shut off valves that had been leaking. I’ve now drained all diesel from my 2 tanks and removed the tanks from boat.
What’s the best way to clean the tanks out?
Would rather make sure all Spick and span before refitting and filling again

 

[burgundyben]

I reckon cleaning tanks is a job that should be done every 5 years or so, its stood me in good stead when I took that approach on an old boat I had for many years, at first I had a load of trouble, nobody had been in the tanks for 40 years, I fitted inspection hatches,. Good clean and scrub, I found fairy liquid worked, traffic film remover works too, but wear gloves. I use a washing up brush on a stick to give it a good scrub, agitate the scum.

Hoover out. Dry out with paper towel, I left mine in the sun when there were out of the boat, the times I did it in the boat I put an electric fan heater in there for a couple of hours to really make sure its all dry.

Then put the fuel back in through one of those water trap filter funnels.

I have used 25 Litre 25L Jerry Can Water / Fuel Container Food Safe Tamper Caps or Tap Caps | eBay

 

[Freebee]

for hard to move or reach contaminants behind baffles etc. put a length of old chain inside and agitate the tank this will loosen things up, but make sure you can get the chain out before you put it in!

 

[Falcoron]

Thanks,
Is it worth rigging up a water trap/filter and put the fuel trough this into newly cleaned tank?

 

[kashurst]

If you take a sample of your fuel in a good clear glass container and look through it with a bright light. It should be crystal clear. If it is hazy there is still water in it.
Any significant amounts of water in your old fuel will settle out to the bottom of the container in a few weeks.
When you pump the old fuel back into your nice clean tank leave the last inch or so to avoid sucking back any crud or water.
The fuel/water separator you linked to aren't great. If you want to put the fuel through a fuel filter/water separator have a look for a racor or racor copy on ebay and pump it through that. Make sure you use a genuine Racor filter insert in it as they have a special water repellant coating as well.

 

[Falcoron]

If you take a sample of your fuel in a good clear glass container and look through it with a bright light. It should be crystal clear. If it is hazy there is still water in it.
Any significant amounts of water in your old fuel will settle out to the bottom of the container in a few weeks.
When you pump the old fuel back into your nice clean tank leave the last inch or so to avoid sucking back any crud or water.
The fuel/water separator you linked to aren't great. If you want to put the fuel through a fuel filter/water separator have a look for a racor or racor copy on ebay and pump it through that. Make sure you use a genuine Racor filter insert in it as they have a special water repellant coating as well.

Ok good advice chears