Coloured Toilet Block in Cistern

[MTbowels]

I've just had a Dudley Duoflush plastic WC cistern installed at home. After the plumber left, I opened the top of the cistern to look inside. I was surprised to find a manufacturer's label on the inside of the cistern stating that coloured toilet disinfectant blocks must not be used in the cistern.

The wife has always used those blue circular blocks in the cistern for their deodorising and cleaning properties. Does anyone know why we cannot use them in the new cistern? I've drawn a blank completely on the web including webpages belonging to the manufacturer.

Thank you.

[Old_Geezer]

When I moved into my present place it had a plastic cistern tank. The blocks I've used have stained it. (Oozes out in crystals around certain areas.) It is probably something to do with it not coping well with the cleaning chemicals.

[tenrec]

My old toilet did the same, where there were any joints, it appeared to leak blue, although there was no leak!

[Prudie]

Is that what they mean by coloured blocks? I'd have assumed it was the type that actually turn the water blue.

[Old_Geezer]

Oh and you ought to be careful swopping colours each time as you get some mixing during the changover even when the water in the cistern had appeared to be clear. For a while, and I don't know how, the bowl looked as it it had yellow water !

[Mosaic]

It is possible that since all internal parts of the flush mechanism are now plastic, immersing them in water filled with bleach etc might make the plastic break down more quickly than normal.

[Segilla]

I found these blocks to be useless in the hard water area where I live. I now use a whole bottle of strong cleaner and leave it overnight.

[DTCwordfan]

wait for Tonyav, his plumbing experience will come to bear and give the answer to this

[argorstran]

I think that bleach etches the surface of the plastic and over a period of time and you end up with a rough surface which is difficult to clean rather than a shiny plastic surface . Same with acrylic bath tubs . Its best to clean these with detergent rather than bleach .

[tonyav]

Crystallisation is the problem.

[MTbowels]

Thanks all. I'll do my best to avoid using them now that I understand the issues at stake.