went with a standard mechanical metered fleck valve and separate tank this time..trust me on this, call someone! it gets complicated as ****, just watch for scammers and overpriced stuff.
but i'll just really blurt out some jibberish i remember..some of it may be incorrect as it's been a year..(so apologies in advance if it's barely coherent)
had kenmore, waterboss. The kenmore types i feel the valves and especially bypass valve are very cheap...typically a thin plastic plunger..i've had that blow apart luckily i was here but it was a mess! I did like the size of the waterboss very much and it does use less water amd salt though i'm not sure of efficiency. i just wanted a better built generic valve unit for a bit more cost. I thought the one i had was undersized and for the larger unit i didn't think a fleck was a bad value. The boss valve is much heavier duty than i see the kenmore types. The fleck and others are REAL heavy duty, my bypass valve is stainless.
ANyways with a separate brine tank you separate the salt from any electronics and stuff, also you can typically locate the brine tank X feet away at a certain slope. You can get these double tanks types that provide continuous soft water but if you get a properly sized single tank it should be recharging when you wouldn't be using water anyways and before the resin capacity is reached thus resulting in hard water.
The science is the same with the 200 dollar dept store units as the 5000 fancy units...ion exchange.
h20 softener capacity depends on the type of resin and the volume of resin and the salt dosage...that's it! more resin more capacity, more salt dose more capacity, high capacity resin = more capacity. Key point this resin has to be 'recharged' with a brine cycle. There is where it gets complicated! Because you also need to know your house flow rate, your hardness, amount of iron,your average water usage for the period of time you're wanting to go between resin recharges (brine flush) in order to property size the unit. However basic water hardness it's pretty simple...aka 7 days capacity determined from h20 water bill weekly average, grains hardness, flow rate (bucket test), figure medium salt dose and you want to recharge 7 or so days. You plug that into the formula and come out with the weekly grain capacity you need between recharges and give yourself some float.
Your X grains hardness, it may even rise and fall throughout the seasons, i don't have high iron but that adds to the size unit you need. In florida my hardness varies wildly summer->fall, i called h20 dept and got the seasonal averages and used the max grains for my calculation/sizing.
You also have to know your water usage, you don't want an undersized unit and be recharging every few days shortening resin, valve life, and wasting water (these things can use 30-60 gallons to recharge though the boss is different) or blowing through salt. You also don't want an undersized unit only removing 1/2 the grains of hardness during a recharge.
You also need to know your flow rate, gpm that you may max typically run, as the softener valve has to deliver that flow rate of softened water.
Very important is salt dose, you can have an undersized softener and use a higher salt dose per regeneration to remove more grains, but of course this uses a lot of salt per year. A lot of the retail units you see are rated at a maximum capacity, ie at the maximum salt dose, great if you want to spend $$, use and lug tons of lbs of salt from the store each year, so you can't go by that rating on the box as it's like air compressors rated at peak HP
Anyways i forget the math (there's lots of online calculators for this) but you end up wanting to recharge every 7 or so days at a moderate salt dosage, that maximizes resin life (supposedly), uses less salt and water. You do your formula and end up with the size unit you need in grains that provides that at the said salt dosage.
Just a random google but you get the idea:
http://www.apswater.com/water_softener_capacity.asp
http://www.watertreatmentguide.com/achieving_brine_efficiency_in_softening.htm
Too low salt dose supposedly isn't good for the resin, and too high your using a ton of salt and need a larger unit. 8lbs seems from reading these guys the recommended sizing.
So let's assume you guy buy a kenmore (doesn't matter all those single tanks at the dept store are the same). It's rated at 32k grain capacity and you need that capacity. So you bring it home plug it in and punch in your hardness, it's going to adjust the salt dosage, only it may be operating at max capacity ..thus costing more in salt and water. Sure it's giving 32k grains hardness but that's with a high salt dose. You'll be spending the difference from the higher capacity unit on salt. If you get TOO high of a capacity unit for your water use you're either:
a) going long periods of times between recharges (supposedly not good for the resin) or
b) recharging too frequently and wasting water and salt (again these can use 30-60 gallon h20 / recharge).
So that's supposedly why you size them.
*Not spamming* just props to an online company i had good experience with ohiopurewater.com, the fglass tanks were made in usa surprisingly, I think the fleck valves are too (can't recall), shipped to door for what I thought was fair deal, helpful over the phone.
Sizing can be a bit complicated reading all i could....after the fact i'd have no problem paying a local dealer selling the same units for much more..only problem is in florida it's FULL of softener scammers and i'd have never trusted them anyways.
