What chemicals are typically added to water to inhibit scale?

Factual Questions
1

I’m trying to prolong the life of my water heater by installing one of these scale inhibition systems.

I assumed it was some sort of filter. But now that I’ve got the thing in my hand I can see the water flows straight through the horizontal part of the T connector with almost no impedance, save for a little opening inside that causes a small amount of water to flow down into the cartridge. I surmise that, by this configuration, no filtering is going on. Rather, I suppose something is added to the water to discourage scale from sticking to the heating elements and other things the water might come into regular contact with.

The cartridge is filled about half way with BB-sized balls of something that sounds like gravel or little bits of ceramic when I shake it. Also it says to replace the cartrige every 6 months, so I guess that’s when the chemicals become depleted.

I am wondering what sorts of chemicals are being injected into the hot water line by this device. Any ideas?

2

If it uses chemicals there will be an MSDS somewhere that you can access. You might want to start there.

3

OK, I lloked around, and on this page they refer to their compound as Siliphos, described as “a 100% pure food grade scale inhibitor approved by USDA”.

Further research comes up with this, which says:

:dubious:

It appears to be some sort of phosphate mixed with silica, which explains the rattling beads that you’re hearing. You can keep looking, hopefully that will get you started.

4

Well that’s just wonderful. I specifically bought this to help prevent scale buildup in a tankless water heater which feeds a steam generator.

:cries:

5

IME, phosphates are the main scale inhibitor used in boiler systems. These pose some environmental hazards, e.g., algal bloom, and are probably contra-indicated for potable water. I have also seen magnetic scale inhibitors advertised, but have no direct knowledge of them (Looks like snake-oil to me, but I am not an expert). For critical anti-scaling applications, revese osmosis and ion-exchange resins are the most common solutions I am aware of. These might be a bit pricey for home applications. You could always try living with the scale for awhile and scheduling a periodic maintenance with vinegar or phosphoric acid.

6

I think it’s snake oil. Suspended solids can be removed during treatment, but it’s not something you normally do at the user level. Check w/ you local utility company, they usually have advice on things like this. They probably have a web site.
This is not, by definition, a filter. It may be some kind of ion exchange device, but even that process usually causes sediment, not reduces it. There are filtration systems designed for homeowner use, but this isn’t one of them. If you haven’t already installed the device I would suggest returning it for a refund.