Flush tank additives

Reluctantly I would side with you Ian 

However we might both be wrong and they may be biological in action unless they say 'non-bio' ??

The bio pods from Lidl are slightly scented, quite pleasant.......and the box says "bio" somewhere on it, if that helps with your other question?

This info comes from OH, who is in charge of these sort of things, well above my pay grade!

Thanks all......

Hi, I'm no expert but I seem to remember when I first learned to drive many years ago that you should not use Washing Up Liquid in your Screen Wash bottle in a car as it is corrosive to the Windscreen rubber seals. For this reason I would be cautious about using it in any part of your Caravan toilet system. Whilst on the subject, and forgive me if I am teaching anyone to suck eggs, but I always spread a thin layer of vaseline over the sliding rubber disk (the bit that allows waste to drop into the tank when you pull the leaver) on our toilet cassette when the caravan is not going to be in use for any period of time. Apparently, the rubber disk will perish if allowed to go bone dry. Hope this helps and does not insult more experienced caravanners than I. 

I've just browsed this topic and it's set me thinking:-

Are alternatives e.g. washing up liquid, windscreen fluid, bio pods etc of any detriment to site disposal systems?

Also, washing up liquid, especially the cheaper brands, can contain sodium (salt) which can accelerate corrosion.

I've always been led to believe that vaseline is harmful to Thetford seals and that a better alternative is a smear of cooking oil.   Just a thought.

I  just  use  the  Dometic  spray,  designed  for  just  that  purpose,  G'day,

A  simple spray  if  the  'van  ain't  going  to  be  used  for a  while.

The  canister  seems  big  enough  to  last  for  ages  --  several  years  at  least.

We've used a recommended lubricant - Silicone (not Vaseline or washing up liquid or paraffin wax) to spray the seals, since we first owned our caravan.  The manufacturers produce their own, but pick up the tin, read it, and buy a proprietary product with the same silicone!  We've replaced the seal once in 17 years, so we must be doing something right. 

Vaseline can rot rubber seals and is not recommended. The correct thing to use is silicone as ValDa says. I use a tube of Silicone grease which I have had for donkey’s years but a spray is just as good. Also for use on O Rings such as the submersible pump connection on the outside of the van.

That’s useful Valda. I need a cassette service kit at the moment- a small trail of drips from the cassette as I pull it along I notice!! YouTube is very useful for learning how to service ones loo.

I used to get black bits in my flush water, mainly when I used cheaper substitutes to Elsan and Thetford etc.  But a couple of years ago the problem seemed to go away and my dealers told me that the Two leading brands had changed their chemical formulae.

In similar form I find that the cheaper and "special deal" Blue liquid is not as effective in controlling odours as the Two main manufacturers Elsan & Thetford. 

I accept that I might be wasting money, but there you are. Its all about consumer confidence I suppose!  I might be literally pouring money down the drain, but hey I'm happy!

TF