For many years I used to buy 25L containers of Comma Xtreme super concentrated screenwash. But that doesnt seem to be available any more.
I bought some Holts concentrated screenwash and made some diluted wash up as per the instructions.
Today I filled up the FL2 washer bottle. The diluted liquid poured OK but then quickly blocked the filter.
On inspection there was a clear gelatinous layer blocking the filter and the same "biofilm strands" seemed to be throughout the remaining 2.5L of diluted screenwash.

Anyone else had "growth" in their screenwash ?

I never had this with the Comma screenwash.

I'll be giving the Holts stuff a miss in future - dont want it blocking up my washer jets.

Anyone recommend a "non-biological" screenwash ?  Jules

Currently using Auto Glym Professional Super Strength screenwash. If there is anything biological in the container it will be well pickled as the liquid smells strongly of alcohol.

I'll have a look - Autoglym makes good stuff.  Jules

jules wrote:

For many years I used to buy 25L containers of Comma Xtreme super concentrated screenwash. But that doesnt seem to be available any more.
I bought some Holts concentrated screenwash and made some diluted wash up as per the instructions.
Today I filled up the FL2 washer bottle. The diluted liquid poured OK but then quickly blocked the filter.
On inspection there was a clear gelatinous layer blocking the filter and the same "biofilm strands" seemed to be throughout the remaining 2.5L of diluted screenwash.

Anyone else had "growth" in their screenwash ?

Hmm that might explain why our shower cublicle glass is the cleanest its ever been  Jules

Have seen it a few times. Had to take the washer pump out of a Renault Clio and de gunk the pump and a little rubber screen at the outlet of the tank.
Just bought a 25L container of concentrated screen wash that will do me for ages. Hope it doesn't start 'growing'. Landrover - turning owners into mechanics since 1948

2014 Orkney grey Freelander SD4 GS.
2004 Zambezi silver Discovery 2 Td5 (Gone)
1963 Surf blue Morris Mini Minor Super de Luxe (my little toy)

Asda 2.5 litre concentrate does this as it gets old, nasty stuff. Biological warfare, I bet it doesn't happen in Electric cars.

Why wouldn't it happen in electric cars? Can't imagine the reservoir or pump would be any different 🤔 Landrover - turning owners into mechanics since 1948

2014 Orkney grey Freelander SD4 GS.
2004 Zambezi silver Discovery 2 Td5 (Gone)
1963 Surf blue Morris Mini Minor Super de Luxe (my little toy)

Satire, just the current electric car jokes. You are right, of course, in fact they are so badly promoted, that people do not know you have to change the anti-freeze in the battery cooling system, either.

Branded screen wash in this country is made by a handful of contract chemical blenders . The formulations will vary widely depending on what the price point will be on the shelf , but they’ll all be a solvent that’s miscible in water , a dye ( want a cheap product to look stronger ? Add more dye ) a surfactant and in some, something like a glycol to add an anti freezing properties . I used to manage one such toll manufacturing plant at the top end of the food chain that supplied a number of manufacturers for first fill on the production line and a lot of top brand names .

Now well into retirement , I have to buy the stuff ! the best bang for your buck for a good all season screenwash at a reasonable price ? Prestone available at from Costco . 2009 GS Auto Zermatt Silver - Sold June 21 after 10 years of ownership

2016 Subaru Outback SE 2.0 diesel SE Premium Lineartronic Sold 2024 after 8 years and 80k miles . Best Car I ever owned !

2023 Toyota Hilux invincible X 2.8 Auto .

Ive bought some Prestone screen wash - will see how it goes / grows  Jules

A few years ago I was engineering manager at an company who make oils / polishes / screenwash / paint etc for the automotive sector. The screenwash was always made using de-ionised water, this inhibits mould growth to give a longer shelf life.
Buying concentrate you have to add tap water, in hard water areas this can lead up to a limescale build-up on the jets - ever had to stick a pin down to clean them?
In soft water areas it tends to lead to mould growth which blocks pumps.
Everything is relative, Reading water is so hard it talks with a Glaswegian accent, Bolton water is so soft it could be called Walter (Beano comic look it up).

I always use premixed as we have very soft water and can't be bothered taking the reservoir out every few years to clean out the insides.

Not long ago the EU banned biocides in paint (due in soon), I wonder have they done the same with screen wash? Tangiers Orange - gone, missing her
Replaced by Ewok what a mistake - now a happy Disco Sport owner

Cheers Andy - that explains it all.

"Buying concentrate you have to add tap water, in hard water areas this can lead up to a limescale build-up on the jets - ever had to stick a pin down to clean them?
In soft water areas it tends to lead to mould growth which blocks pumps"

We have soft Severn Trent water.

So I just need lots of de-ionised water to dilute the concentrate

And/or store the dilute mix away from any light.

I usually use white semi-transparent 5L containers but I think I will only use black plastic from now. Jules

If you I have a condensing tumble drier the condensate would be almost distilled water. There’ll be some perfume from any fabric conditioner that is used but it will certainly be mineral free water.

Demineralised water isn't the same as distilled water, but condensed water from a tumbly should be reasonably distilled though the condenser can introduce contaminants depending on the filter my PC is slightly to the right of Genghis
2012 HSE SD4 In Orkney Grey now gone, best car ever.