Q: We are a new dealership and are trying to establish our product line. Are shower filter and faucet filters viable products for us to market? I know we will be using faucet-mounted filters and drinking water faucets. Do we have to be concerned about lead being imparted to the water when we use the drinking water faucets?

We are also being offered "depth filter" cartridges. Is this just marketing talk or are there some real advantages?

A: Both faucet filters and shower filters are viable and will perform as advertised. You should be careful, though, that you apply them correctly. These come in many choices of filtration media. If you have a customer who is concerned about chlorine in their water, then you would use an activated carbon or a KDF cartridge. If sediment is the concern, then you would recommend a cartridge that removes particulate matter. There may be other types that I am not aware of.

There is no concern about these faucets imparting lead into the treated water because manufacturers of drinking water faucets have been using lead-free materials for many years. Brass is the material that contains some percent of lead and would particularly be a concern when used with RO systems. Current materials are typically stainless steels or plastics.

These products will probably not be a primary source of income but would certainly be a viable adjunct to your whole-house products. Also, they may be a good source of repetitive income due to the need for regular replacement cartridges.

Depth filter cartridges have definite advantages if there is a need to remove sediment of unknown particle size or if there is a range of sizes. These filters remove the largest particles without plugging at their surface where the filter is the "coarsest." As finer particles pass through the filter they are removed by progressively finer filter fibers. The end result is that the filter will not become plugged-up at its surface, but will still remove very fine material for more gallons and with less pressure loss.

Q: We are an equipment manufacturer who has a dealer with an industrial customer, operating 24 hours per day, with twin 30-inch diameter softeners. Twice in the last six months we have had to replace a tank and the dealer has repaired plumbing leaks. Obviously, the tanks are the big issue. We have discussed this with our tank supplier to no avail. They don't know why the tanks are failing and are refusing to replace any more because they insist that the pressure is too high.

We have provided pressure gauges and our dealer checks them regularly. The pressure usually reads between 60 and 80 psi. Therefore, we don't think it's a pressure problem. What else can we do to identify the problem?

A: I have seen this before and I would probably agree with the tank manufacturer. I suggest that when other industrial entities in your city, which do not operate 24 hours per day, shut down, the incoming line pressure in this facility rises to a level that exceeds the operating pressure of the softener tanks. Your dealer is probably checking the pressure gauges during business hours when the pressure is normal.

You or your dealer should locate inlet pressure gauges, which have two hands. One hand operates in the normal fashion where it goes up or down depending on the pressure. The other, sometimes called a "lazy" hand, remains at the highest pressure that it senses, until manually reset. This way the dealer can check a gauge in the morning and easily see the highest pressure that the equipment was subjected to since the previous day.

In my experience I have seen these "lazy" hands read up to 150 psi, much to the surprise of all concerned. If this is the case, then it is not a faulty tank(s).

Normally this would never occur because municipal water systems do not allow the pressure to rise to this level, but it happens. Aside from having a serious talk with the water department, you should install a pressure regulator at the inlet to the building to protect not only the softeners, but also all the plumbing components.

Q: Our dealership buys resin either from a broker or from a larger dealer in our area. We don't get a lot of technical resin knowledge from these sources so we are at somewhat of a disadvantage.

Our question has to do with the term "DVB." We have a competitor who promotes high DVB resin, which supposedly has more chlorine resistance. Of what use is this claim and what does DVB have to do with it?

A: DVB is an abbreviation for divinylbenzene. DVB is the "glue," or binding agent that holds the functional part of the resin together. It's what maintains the resin's spherical configuration. It does not contribute to the ion exchange function of resin.

Chlorine reacts with DVB in such a way that the DVB no longer stays intact. Hence, the binding agent can no longer serve to maintain the spherical bead shape. When this happens the resin still has its ion exchange function, but it turns to a shapeless mush. This results in three undesirable conditions: Having no voids or spaces between the beads, pressure loss through the resin bed increases; the resin swells in volume so that the bed depth increases; and ultimately, it breaks apart and is backwashed to the drain.

Standard softening resin contains about 8 percent DVB. When the DVB is increased, to 10 or 12 percent (this is a manufacturing function and adds some cost), it doesn't make the resin chlorine resistant but rather extends the time that the resin lasts before the DVB degradation takes place.

So, providing that your customers are using city water, you too could sell resin that contains more DVB and will resist chlorine a little longer.

David M. Bauman, CWS-VI, CI, CCO, is technical editor of Water Technology^® and a water treatment consultant in Manitowoc, Wis. He received his B.A. from the University of Illinois in Industrial Design. He can be reached by email at: dp-bauman@sbcglobal.net.