Cleaning the grey waste tank

[Uluru1]

I am winterising my Hymer Ayres Rock. The instruction booklet refers to rinsing out the grey waste tank through the "water cleaning opening." Can anybody advise where that is?

 

[Jo May]

We put some Elsan Organic down the sink / shower etc. left it for a while and flushed it through the waste outlet. All seems clean.
(Not a Hymer with a dedicated water cleaning opening)

 

[Nanniemate]

I pour Milton down the plug holes rinse through the let it slosh about and drain .seems to work

 

[hja]

I use Fenwicks grey tank cleaner. Usually just before a trip out so it can slosh around and then be drained. Also when using puriclean in fresh tank always drain some of that into waste tank.

 

[Lenny HB]

I expect they mean service hatch a big round red cap on the top of the tank.
On our last stop of a trip I don't drain the waste, I put a dissolved dishwasher tablet down the sink with a fair bit of hot water then empty the tank when I get home.

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[Larrynwin]

I wait until the tank is nearly full then add some detergent and w up liquid and before leaving for home partially open the drain valve

 

[Uluru1]

Great. Thanks all for your advice.

 

[Verteuil Man]

One your last trip before winterising, in the empty tank put 2 x 2 litre bottles of roller cola down the sink plug. On the drive home it will clean alsorts of nasties and smells.

 

[Kenp]

I wait until the tank is nearly full then add some detergent and w up liquid and before leaving for home partially open the drain valve

I feel for the cyclist and biker who follow you.

 

[nicholsong]

Why clean it when the next use is to put dirty water down it?

We do not get smells because we have 'U' bends.

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[Fazerstorm]

Why clean it when the next use is to put dirty water down it?

We do not get smells because we have 'U' bends.

The only reason I clean it, is because heavy build up in the tank can cause the level indicator to go haywire. We have had it suddenly go into alarm in the middle of the night, even though the tank is empty!

 

[Richard J]

I get some cheap citric acid 250g from Amazon, dissolve it in the sink and wash it down with 3/4 tank of water then drive home and empty. I think it clears the soap and fat scum

 

[Lenny HB]

I get some cheap citric acid 250g from Amazon, dissolve it in the sink and wash it down with 3/4 tank of water then drive home and empty. I think it clears the soap and fat scum

Used to use that for the loo but found a dishwasher tab works as well and always have them around.

 

[BeeHappy]

I pour Milton down the plug holes rinse through the let it slosh about and drain .seems to work

That’s my tactic as well. Every few trips I put a bucket of warm water with Milton fluid down the sinks and shower before I set off so it can slosh about in the empty tank. Then drain down at the site while I’m filling water. Not sure if it’s really making any difference but seems to keep the sink draining well!

 

[Geoff51]

Why clean it when the next use is to put dirty water down it?

We do not get smells because we have 'U' bends.

No trap on twin 640 bathroom basin. Needs flushing with Milton. It’s not the waste water it’s what’s growing in the waste tank that causes the odour.

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[Pedro Pallent]

I use Milton, and then fill to half full, then use self levelling to empty the tank

 

[The Ice Man]

I have a bit simpler system just drop a few steradent tablets into the tank and fill your sinks and any other waste water points with steradent tablets mixed with water drain it all down into the tank leave couple of days and flush out the tank with fresh water. As for the tank filler you should have an access lid which on a PVC is sometimes on the outside of the van ?
You can use the same steradent trick with your fresh water as well because steradent doesn’t taint the fresh water system.
Another one I used to use on the waste tank was dilute orange juice pour at least 2 or more litres of cheap stuff throughout the waste system leave for a day or two and the juice will kill a lot of the bacteria in the tank that can cause smells.
Be very wary of using Milton as has a powerfully strong chemical reaction and scan damage plastic piping and seals.

 

[Pedro Pallent]

Sounds like a good plan

 

[FrankNicklin]

Do not use Milton on Stainless steel, it is extremely damaging. If it gets in to your hot water heater it will do irreparable damage. See H290 hazardous chemicals may cause damage to metals. Sodium hypochlorite solution (bleaches like Milton) is very corrosive to most metals (except titanium) and will soon remove the stainless properties of stainless steel.

 

[FrankNicklin]

Be very wary of using Milton as has a powerfully strong chemical reaction and scan damage plastic piping and seals.

Milton is used to sterilise baby equipment which is mainly rubber, silicon and plastic. Milton is extremely damaging to stainless steel so can damage sinks and heater tanks especially if left to stand for any length of time. It causes pitting of the surface and destroys the stainless properties of the steel.

https://bssa.org.uk/bssa_articles/selection-of-stainless-steels-for-handling-sodium-hypochlorite-naocl/#:~:text=Contact with household bleach,left overnight, pitting can result.