How do you clean out a freshwater tank?

I want to flush out and clean the fresh water tank on my Broadway.  However, with the Whale socket filler it is not possible to pour cleaning fluid (Puriclean) directly in to the tank.  Has anyone got a simple solution for cleaning a freshwater tank with this type of filler socket?

Dilute the cleaning fluid in a bucket of water and pump it in with the external whale pump. Then use the hose to fill the tank.

Hi Andrew depends how clean you want your tank. If underslung it is as  simple as undoing 2 nuts and removing 2 others to drop the tank enough to gain access to the top. I did this to replace the internal pump in a van conversion   but took the opportunity to wipe out any crud using  plenty of kitchen roll. Then used a hose with jet to flush the inside . Opening the drain tap allows any remaining slime to be flushed out. Depends on how keen and  able  you are crawling underneath but puting the van on ramps or blocks is enough to gain access and a cardboard box cut down was enough to support the tank as I did not disconnect any other pipes or wires. If less keen and just want a quick freshen up do as Peter says above but rinse well afterwards.

As Peter says just put some cleaner into the water before pumping it in... Run your internal taps for a few seconds then leave overnight, drain down & rinse through before use.

For what it’s worth I’d only use or recommend Elsan products which I consider to be the best & are also very well priced 

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If Zappy's Tablets are still available they were an easy and effective option. Very cheap too, but I don't think Graham is trading any longer.

If anyone can find him, or suggest where else they can be obtained, I'm sure a number of members would be interested.

They were highly soluble sodium hypochlorite tablets, each containing one gram of chlorine. I've got his instructions somewhere, saying how many tablets per volume of water, and how best to do the job.

Or you could cut a hole in the tank and put in a hatch (Henderson hatches?) and never have to worry about pump failures, gauges or smelly tanks ever again as you can fix them in a heartbeat

groundhog wrote:Or you could cut a hole in the tank and put in a hatch (Henderson hatches?) and never have to worry about pump failures, gauges or smelly tanks ever again as you can fix them in a heartbeat

Hi Hog

Why did I never think of doing that?
How easy it is to miss the obvious until some clever sod mentions it! 
It's so obvious (Doh!!) Thank you, and please continue to be a clever sod! 

Do I detect a whiff of sarcasm Dave?

I never thought of it either, it was the brilliant guys at Marquis in Plymouth who fitted it when my water pump packed up! It was quicker and easier than dropping the tank to replace the old pump! Might not work on all models but I have found it a brilliant mod that cost me nowt but would not have been expensive anyway!

Great for hiding contraband too if that is your thing!!

Sometimes Marquis and brilliant do go in the same sentence!

Regards
'hog

groundhog wrote:Do I detect a whiff of sarcasm Dave?

Not at all. 

Just amazed at myself for not thinking of something so transparently obvious!!

I need not have had the Shurflo fitted - but I'm glad I did as it's vastly superior and it actually works straight away after a drain down.

Gromit wrote:

groundhog wrote:Or you could cut a hole in the tank and put in a hatch (Henderson hatches?) and never have to worry about pump failures, gauges or smelly tanks ever again as you can fix them in a heartbeat

Hi Hog

Why did I never think of doing that?
How easy it is to miss the obvious until some clever sod mentions it! 
It's so obvious (Doh!!) Thank you, and please continue to be a clever sod! 

A good suggestion Hog,
It seems a much simpler (and indeed far quicker?) solution to most, if not all, of the "inside tank issues" that have been raised in the past here on the forum.
Henderson Hatches have been noted in my "in case I need it in the future" list.

Evening all 
Our sigma came with an Henderson inspection hatch on the underside of the tank 
I thought it was originaly fited to allow the fitter to get his hand in to fit  the take off fittings
Having had water tanks on boats for years and been caught out with bad water  and nowhere to get it replaced at sea I'm very fussy about tanks 
I took ours off and gave it a very good clean inside and out including all the fittings and piping outher than the blue pipe which was flushed through with millton on reasonable 
Bit over the top I know but I said I'm fussy  we drink water from the tank with no problems 
Jim

Our previous Autocruise had a hatch on the top of the tank and a lift out floor panel in the habitation area, you could fill the tank straight from a hose, bucket or whatever and obviously get in there without taking your regulation white trousers off in the evening.... 
Now that is clever and so simple. A/S please note

CC , i have an identical MOHO to you but an 59 reg which i have owned for a year  ,a question to you is how do you get water in to the tank regarding cleaning fluids ,i also have the Truma ultra flow system which i use the Blue hose system to fill the tank, i see for sale 2 types one with a pump another not which system were A/S using at that time ,i thank you for any info Barrie