Hi folks. Bin at it readin for a while. Think I might be getting a sense of this wfp trick by now. Got to talkin with a local residential water specialist today. He seemed to see how one of his big DI tanks might help me out but was troubled at my mention of RO. He said the water condition in these parts is bad enough to destroy RO filters. In houses he has to install a large water softener contraption to protect the ROs that he puts in. His take on our water supply here was 20g/gallon which he said converted to 342ppm. As far as window cleaning goes we all carry a good supply of phosphoric acid because sure enough any window with sprinklers nearby will be spotted with deposits.
I also have to use a fine mesh filter in my drip irrigation system as there is a good supply of algae in the town water and my under sink carbon sediment filter clogs instantly unless I run a particle filter before it.
Is my water too hard/gross for RO or is the residential installer who helped me not aware of how multistage WFP systems are designed?
Well I have kept at it. Now I know. Indeed water softeners are used in multistage pure water window cleaning systems for hard water conditions. But where are they in North America? I’ve been browsing US window cleaning supply web sites and have yet to see one posted in a catalog. ‘No Results’ when I searched WCR. Even after reading a post where Bill recommended one sold from this very site. The UK folks are not hiding them however… with their supplier even offering up a full description of how it extends the life of an RO membrane and how to maintain it properly.
It might be because the FDA has limits on what is acceptable for TDS levels. I do believe reading here that anything over 500 is illegal and must be fixed. No demand = no market.
Interesting problem. Would the Eagle 5 stage system not work? Is the algae in the water the problem? I would think you could get a water test kit to see what specifics you are dealing with. If the RO being overwhelmed is the concern isn’t the prefilters and carbon filter sufficient as the TDS is already considerably lower by the time the water hits the RO?
There’s some knowledgeable guys out here, someone can crunch this problem.
I’m at 1400 tds somedays here in Spain. The UK is generally around 600 tds in the harder areas. Basically get some good pre-filters. I change mine every 1000 kilos. Back flush for 2 hours before & after production. But then again, I make my water in house & take it with me. This may be a better option for you. 99% of window cleaners in Europe do it this way.*
I run a conditioner ahead of my stationary RO for that very reason. RO membranes would last indefitianly if not for calcium/magnesium etc. in the feed water stream forming scale on the membrane surface. That’s why they have to be eventually replaced. They do not ware out as some think. A water conditioner swaps salt (Nacl) ions for the cal/mag ions (thus “softening”) the water. Salt ions will not stick to the membrane surface and cause scaling (pluging the holes). Now on the otherhand Chlorine will destroy the membrane surface. Thus the need for a degassing filter ahead of the menbeane .(carbon, chared coconut, etc.)
The high TDS in Europe is probably why water softeners are more present to window cleaners. As far as in house production goes… I am starting to lean towards setting up that way. At first I thought lugging that water around would be too much extra work. But showing up on the job ready to start cleaning will pay off when it is hard to find a water source.
This is exactly what the residential water specialist was recommending but I could find no trace of water softening in WFP systems until I looked at European suppliers. There are a couple trolley and van systems over there with softeners included. I am thinking an in house system set up with a residential softener would be a good way to help the RO last indefinitely. Some say though that the RO replacement cost in the cart systems here wont be that bad and to just get on with cleanin windows. I finally got my TDS meter and took a reading from my tap. Ken was right on the money, 300ppm. With his residential customers he definitely wants to prevent complaints so prefers to set up RO with softeners to protect them.
