[ftp]

Had an industrial unit to do today - mostly upvc with little glass in a sorry state. I attacked everything with tfr and worked my nuts off to get it clean. However the tfr ran down the glass and dried leaving stains. Anyone else had this? Did you get them off?

[Pj]

Yes

It requires something like a mild vehicle cutting compound.

I've stopped using TFR for that reason.

[Steve CM]

as soon as you spray it will agitate. don't spray and leave it

[Robin Ray]

Yes exactly the same thing!

Have been advised dont let it dry and dont have it too strong. Havnt had any problems since.

[Dave Turley]

i've had this problem a few times in the last few weeks, I think mainly due to the hot weather and using a strong tfr solution.

you need to wash/brush the tfr off any glass asap after application so it doesn't dry.

I got the marks off with some more tfr on a non-scratch scourer and then wash off again. they can be murder to get off.

what strength tfr do you all use. i've used as strong as 50/50 but I don't think i'll be doing that again

[ftp]

Probably close to 50 50. Far too strong I know, but the stuff I have does bugger all at low dilution rates. I honestly believe TFR is the wrong stuff for algae removal, I believe it's too far towards being a degreaser. I reckon a detergent like a washing machine fluid or a high soap solution would be just as good maybe better.

[Dave Turley]

I think you can get proper algae remover, but I do love the way tfr just melts all that green on conservatory roofs!