Toilet flush problem

It's algae caused by the pink flushing additive. Stop using pink and it will eventually go away.

Yes algae from pink additive.  You don't have any additive in the wc flush at home so I do not use anything in the flush in my caravan.  

Easy don't leave the pink flush in the tank when your motorhome is not in use

Better still, don’t use it at all. Save a few £ and stop getting algae in one easy move. It’s totally unnecessary to add it to the flush water and we haven’t used it for many, many years. Our current van uses the fresh water tank for flushing so there’s no way we could use it even if we wanted to.

But toilets at home don't flush into a holding cassette & use somewhat more water .... I just use a splash of pink in the flush tank which doesn't produce black bits. But Anyway .... black don't cause any harm .... they get flushed away. 

We flush direct from the water tank, but my wife likes to regularly spray that pink stuff around the bowl to make the loo smell nicer. When she does I notice black bits when emptying the cassette and it’s not no 2s!

We use the pink flush and after the flush we press the flush button thus leaving the pink flush in the bowl thus no smells. The only time we have had black bits is when I forgot to empty the flush tank

All of the above is valid but I would thoroughly flush the toilet flush header tank with clean water.From personal experience,the black gunge can seize up the flush pump impellor.This is rectifiable by removing and cleaning the pump but it involves a lot of hand contortion and much cursing of the toilet's designer.It is also a pain to fit the pump and flush jet back in their locations.- I know having done it.Prevention is better than cure,believe me!

Plain water in the flush tank, and a hand spray of diluted scented Zoflora disinfectant around the bowl. You could also add a splash of the Zoflora to the tank if you wish. The blacklist will eventually disappear.

I went green some years ago and have no black bits problem. Just one bottle to carry with just use a dash to colour the flush water whilst adding 75g of fluid and 2L of water in the waste tank. No smells, no problems, easy.

Colin