[Shiners Express Ltd.]

Have any of you been getting problems with spotting in this warmer weather

Strangely this only occurs on windows that are being cleaned in direct sunlight. Windows in the shade are not spotting.

Have checked the TDS of production system output which never seems to change from the usual 25ppm. Swapped vehicles to see if it was a problem unique to one van with no obvious change. Even spending slightly longer rinsing doesn't seem to improve things.

If I can't find an alternative cause, the only thing left to try is a new set of 4040 membranes 

Any ideas ?

[Erithwc]

Turn the flow up.

Paul

[H S and Son]

I think the clue is in the second line of your OP.

[Ian101]

U for real 25ppm ... Think that may be your problem

[colin purewater]

Buy some resin ye meff

[Dave Willis]

I can see some work coming my way in Wiltshire soon 

[Smudger]

I think the clue is in the second line of your OP.

are you sure Matt ?  - i thought 3rd line had the answer  

Darran

[Window Washers]

25 tds  : <rolling eyes> 

pure water equals 0.00 tds no wonder your getting spots keep it at 000 and you can nver blame the water.

[Shiners Express Ltd.]

BUY RESIN!!! lmao

We haven't used resin for almost 5 years and have never had this problem before!! Only found out by accident that if your RO produce is low enough, you don't need it. As some of you may know, i used to work for one of the large system manufacturers so I know what i'm talking about. HOWEVER!!! this situation really has me stumped!

We go through anything between 1200 and 1800 ltrs per day at the moment, so really don't want to start using resin again! especially if there's been no need for it during any summers in the past!

[Perfect Windows]

Any ideas ?

Try using pure water

[Window Washers]

BUY RESIN!!! lmao

We haven't used resin for almost 5 years and have never had this problem before!! Only found out by accident that if your RO produce is low enough, you don't need it. As some of you may know, i used to work for one of the large system manufacturers so I know what i'm talking about. HOWEVER!!! this situation really has me stumped!

We go through anything between 1200 and 1800 ltrs per day at the moment, so really don't want to start using resin again! especially if there's been no need for it during any summers in the past!

it does not cost that much for resin, I use near on what you do per day, use twin di the costs are minimal, do you advertise your using pure water ?

[richard jagger]

25 ppm on sunny days will spot.Those 25 particles are been concentrated in each droplet as they dry to quickly on a window.When the water dries slowly the particles are dispersed across the glass and not been drawn into the droplets.One can get away in a damp cooler weather with a 25 ppm but not when its hot and dry.Its quite logical if one just understands how it would work.

[Shiners Express Ltd.]

Wizkid, I understand what you are saying, but surely the direct sunlight/temperature only effects the drying time, not the concentrate of tds per droplet?

[Shiners Express Ltd.]

Window Washers, do you mind me asking how often you change your resin and what you're using?

We used to use MB400 at about £90/25ltrs.

[Window Washers]

Window Washers, do you mind me asking how often you change your resin and what you're using?

We used to use MB400 at about £90/25ltrs.

I just changed some I have twin di that hold a sack each, normally once every 6 months ish depends how much water I use, I replaced both when I moved units about 18 months ago even I was shocked at how long it lasted.

I use tulsian 115  from daqua.co.uk
couple of bags cost : 2 Bags - £59.50 each (£71.40 including vat and UK delivery) one bag is 62.92+vat £75.50 including vat and UK delivery

your tds out of ro is quite high, I would defo look at reducing that too
 

[Shiners Express Ltd.]

At what stage are you putting the water through the resin then?

We have a main production unit, then transfer to the vans every day. I'm guessing the best would be just before the holding tanks on the production unit?

What you getting out of RO's then?

[richard jagger]

AS a drop of water dryes  the particles of impurities in the water will move to the crest of the meniscus( the rounded top)  of droplet and avoid the sides.Plus the particles will concentrate from the water that has already dried. If one tested the droplet of water just before it dried you would find that its TDS would reach a higher volume of particles.Pushing the tds to 50/60 which would form a drop shape mark.

When water evaporates slowly the particles will be spread evenly over the glass and will not be seen by the eye.Hope this helps to understand your problem.
 
Your D I works as a safe guard working as quality controller on your water, Even if you feel you do not need a di its is wise to use one as the R O is less stable and can charge quickly if it is becoming worn out IF you do not need a DI it will cost nothing to run as it will use no reason but will be a safe guard.

[Shiners Express Ltd.]

Thanks for your help Wizkid, in theory I completely agree with what you're saying, but it doesn't explain why we've never had this problem before!! Think i'm going to have to bite the bullet and go back to DI resin  

Must remember to ask the mrs if she'd like some meniscus later!!! lmao

[Window Washers]

At what stage are you putting the water through the resin then?

We have a main production unit, then transfer to the vans every day. I'm guessing the best would be just before the holding tanks on the production unit?

What you getting out of RO's then?

I put through resin jsut before going into holding tank, I pump pure into vans, sod carrying resin in the van or pumping it through resin at the spped my transfer pump goes it would not work anyway.
transfer pump is doing 650l in under 10 mins
at the moment its about ro out is 13
I do flush everytime I fill

what waste to pure are you getting for 25 ?

[ben M]

At what stage are you putting the water through the resin then?

We have a main production unit, then transfer to the vans every day. I'm guessing the best would be just before the holding tanks on the production unit?

What you getting out of RO's then?

I put through resin jsut before going into holding tank, I pump pure into vans, sod carrying resin in the van or pumping it through resin at the spped my transfer pump goes it would not work anyway.
transfer pump is doing 650l in under 10 mins
at the moment its about ro out is 13
I do flush everytime I fill

what waste to pure are you getting for 25 ?

how do you flush your ro?
thanks