Relying on a water report to correctly size a softener isn't the best way. Things happen to the water after it leaves the municipal facility and travels miles and miles to your home. Always best to get a comprehensive water test at the location where you'll be treating the water.

"Water softener tank is changed out weekly"

Does your 2.5 cube softener regenerate on site or is the resin tank exchanged by Culligan weekly?

Is your BIG BLUE a real Big Blue @ 4.5" x 20" or the toy 10"?

If the softener regenerates then the Big Blue may restrict the water flow enough to not adequately regenerate the resin. You might need to add a second Big Blue in parallel or a backwashing carbon filter is preferable ahead of the softener.

Your 2.5 cube softener is way too large for your water conditions and two people, but about right for four people FULL TIME. You could be experiencing channeling and that will allow hard water to leak through.

Have you tested your hardness mid week and then again as the softener reaches depletion at the end of the week to make sure the water holds 0 hardness all the way as it should?

Have you discussed these problems with Culligan?

This post was edited by justalurker on Mon, Jul 1, 13 at 23:55

Yes, I did in fact discuss with DH about getting the water tested by an independent lab, although I suppose such testing tells us about the water quality at a specific point in time and may be subject to variation over a longer duration. But objective and accurate analysis is better than none!

The softener tank is exchanged by Culligan each week. When I asked them about the spotting, they only said it shouldn't be happening. I have just inquired about a KCl softener from them and they'll come out to check the feasibility. Customer Service said something about the KCl softener being an "auto-softener" and that we'd need an outlet and drain. So I assume that means it will be on-site regeneration.

Could a KCl softener possibly result in less spotting?

I'll have to also ask them about the channeling you refer to.

The Big Blue is indeed the 20" (and it precedes the softener).

I figured the 2.5 cu ft was too big for just the 2 of us, but since having 4 at home is not on a scheduled basis, then I prefer to have too much than too little available for the ad hoc occasions.

I'll have to give the mid-week and end-of-week testing a try. In that regard, I'd appreciate hearing of others' experiences (i.e., reliability) regarding retail test kits such as these found on Amazon:
"Water Safe WS425B"
"First Alert WT1"
"HM Digital TDS EZ" gauge (but only TDS)
"Hardness Test Kit (CaCO3)"

(Other recommended retail test kit suggests are appreciated!)

Many thanks!

KCl is potassium chloride and simply a no sodium substitute regenerant for NaCl which can be used in ANY ion exchange regenerating softener. KCl will not eliminate the spots so perhaps you misheard what thy said.

Needing an outlet and a drain means a regenerating softener and IMO is a better idea.

Too big a softener is not better and brings more problems than people and many softener salesman understand. Just right is what you want and it's easy to calculate and it will simply regenerate more often when the kids are home. That is the beauty of an on demand regenerating softener.

"When I asked them about the spotting, they only said it shouldn't be happening"

You should find yourself a water treatment professional who knows what they are doing cause your Culligan people don't seem to.

I'd recommend a water test by an independent certified lab. Based on those findings I'd get an industry standard softener correctly sized for the water conditions and you two and set up to run efficiently. I'd determine the SFR of the plumbing and fixtures and then add a second BB 20" in parallel to the first with pressure gauges before and after each filter so you'd know when the pressure drop indicates filter replacement is necessary OR get a correctly sized backwashing carbon filter to place ahead of the softener and remove the BB filter canister.

When that is done correctly you should be where you want and if not resolving problems will be a lot easier.

Any TDS meter is OK and the $12-$30 ones are fine. There's always TDSmeter.com if you want to go nuts

For hardness testing the Hach 5b is pretty popular.

This post was edited by justalurker on Tue, Jul 2, 13 at 1:11

Darn (about the KCl not being better than NaCl for spotting)! Any idea about whole house RO?

Do you also know if KCl "feels" the same as NaCl (the "slick" feeling of the water when sudsing and rinsing)?

If it turns out that we have an appropriate outlet and drain then we might look into this option; and then we could address "right-sizing" for our household.

Luckily we have a EPA certified lab near DH's workplace!

I know I can simply Google for an online calculator, but if you (or anyone else) can recommend an effective calculator for right-sizing a softener, I'd be grateful!

Thanks for the TDSmeter.com lead -- I found most of their products on Amazon as well as the Hach 5b kit. I'll try the AP-1 since it has larger read-out (for aging eyes)!

You (justalurker) have been so quick with your suggestions/comments and I really appreciate it! This is a new subject matter for me and I'm trying to ramp up as quickly as possible. Thanks a bunch!

Whole house RO is BIG, expensive, maintenance intensive, and RO water is very aggressive. Put whole house RO out of your mind.

With your hardness and TDS I would recommend a quality RO under the kitchen sink for cooking, drinking, and ice maker.

Soft water regenerated with KCl or NaCl feels the same. NaCl costs about $4 for a 40 lb bag while KCl costs upwards of $25 for a 40 lb bag.. The specific gravity of KCl is different than NaCl so you'll use more. Unless you are on a low or no salt diet NaCl makes sense.

Post these results from your lab... hardness, iron, manganese, TDS, pH.

Calculate your SFR (service flow rate).

We already know 2 people and two bathrooms.

With that info I can tell you the correct size softener.

You can Google for online softener calculators but they are usually wrong as they are too general and don't take some factors into account..

Water spots are a common problem and can be hard to beat in some circumstances. They can be formed from the sodium (exchanged for hardness at 2 ions to 1) or potassium (exchanged for hardness at 3 ions to 1) exchanged into the hard water to make it soft. They can be from TDS. They can be from silica and other things. Sometimes spots can't be eliminated only minimized.

Another option depending on how often the kids come home is a twin resin tank softener. The advantages would be...

1. makes brine for regen with soft water

2. regenerates resin with soft water gives longer resin life

3. soft water 24/7 and will regenerate when it needs to and you still have soft water while regenerating

4. will accommodate changes in water use and you'll never know it

This is so helpful! I'll post when I have the lab results.

Appreciate the advice regarding WH RO and about twin resin tank.

Don't forget your SFR... it is an important factor in softener sizing that is too often overlooked or ignored.

Using the bathtub as the measuring point, open BOTH the hot and cold water faucets completely open.

Place a 1 gallon container under the faucet and measure the amount of time it takes to fill the container in seconds.

EXAMPLE: one gallon in 5 seconds = 12 gpm

Ah, yes,! I had read some earlier threads and so in fact I ran the showers and kitchen sinks, filling to 1 gallon and timing it. Thus the flow rates I previously mentioned are based upon those actual measurements (and not just the manufacturer's published flow rate). Unfortunately our bathroom basin sinks are too shallow for me to be able to fit a gallon pail to test their flow rate. Although I could use a 2 or maybe 4-cup measuring cup and then extrapolate...

Does the flow rate of the washer and dishwasher matter? I'm having difficulty tracking that information down in published literature.

You also mentioned silica...do you know if it helps to measure this mineral in our water analysis? Can softeners effectively address silica or is this something for a filter to address (and can it effectively be filtered)?

Re-reading your first post you wrote that the tub is 3.125 gpm and that is VERY low. More than likely the tub has a tempering valve.

With two tankless water heaters you ought to be getting upwards of 9 gpm or something is wrong. What size is the water service line? 3/4" or 1" or 1.25"?

You only need the SFR from the highest flowing fixture. Usually a bath tub that doesn't have a tempering valve or an outside hose bib. Pull the element from your big blue and bypass your softener and then try the bucket test.

Trying to determine real world performance from a spec sheet is a waste of time. That's why you put a bucket under the tub spout and measure YOUR real world SFR.