For an RO that will feed the refrigerator, I highly recommend a system that uses an Aquatec Permeate Pump. The 2.5 cu. ft. 7000SXT will be fine for your application.
8% is fine unless you have a decent amount of chlorine. If you have anything over 1 ppm, then a 10% crosslink resin is highly recommended or pre-treat the system with GAC.
A twin is calculated as to the max number of gallons the same as a regular softener, and then you subtract the gallons (or grains) used to regenerate either tank. Many twin tanks will regenerate more frequently than a correctly sized regular softener. Some twins will regenerate multiple times a day.
If you add up the salt used for both types of softeners over the number of days the correctly sized regular softener with the same type of resin regenerates, it is a rare twin that will get better salt efficiency and in many cases it will use more, and that includes subtracting the number of gallons or grains for a 24 hr reserve in the regular type softener.
Another problem with a twin is that most do not allow water through both tanks at the same time so, you get to suffer a reduced flow when one tank or the other goes into regeneration. AND more reduction, equal to the gpm of the drain line flow rate, during regeneration. IOWs, your SFR gpm is reduced by more than half. And recall that you have to be using water to cause a twin tank to go into regeneration, and usually you do not shut off your use so you must live with the reduction in flow rate. Especially if you happen to be in the shower.
We are talking about the tank providing the softened water used for regeneration of the other tank. You subtract the gallons or grains of capacity to soften the water used to regenerate each tank of a twin tank softener. The instructions are in the Fleck manual for whatever twin tank valve you are using.
You obviously have no clue as to how a twin alrtenating softener works, so I will discontinue trying to educate you on it. You can argue all day long, you are simply wrong on this one. no big deal, I tried. Common sense cant be taught.
Peak flow rates of softeners is in most of the major system manufacturers catalogs, I have posted these for you in the past, you must have forgotten (or chose to ignore) that information. Peak sytem flow rates are typically done at a 15 PSI drop across the system, not just the valve. You are correct that many companies wrongly post the maximum flow rates of the valves and not the systems. As I have said so many times, there are a lot of unqualified, untrained, uncertified, and unlicensed people out there who think they know water. They have enough knowledge to fake it, but when it gets into more complex issues, IE: twin alternating systems, their true depth of knowledge and experience is exposed.
And, if you are able to read without desperatley trying to make some stupid point, you will see that I stated that larger systems have maximum and minimum recommended flow rates. I also said that in general it is not critical, but it is there for a reason. Extended flow rates outside these recommended flow rates can cause problems. Occassional use outside these recommendations are typically not a problem.
Now please try to add something beneficial to the discussion rather than trying to challenge my knowledge and expertise in a weird effort to show your Alpha male prowess on this forum.
I am just glad you guys are here and have helped me along on what I should purchase (to get better water of course).
I suspect you both have good ways of doing things and experience. Just like in Math and most things in life, there are usually multiple ways of doing something.
Like I said, your ignorance is showing.
I'll take that to mean you can't prove any of that wrong.
I have already explained it to you in other threads, you are simply incapable of understanding it. Your explanation is ridiculously flawed and from that I can see that no matter how much I explain it to you, you will not understand, or you will disagree so you can keep a thread going for no good reason, it is called trolling.
More of your unsubstantiated claims and again no proof of them or any correction of what I said.
I'm beginning to think you don't know how a twin tank is programed. As I said the instructions are in the Fleck twin control valve manuals. They actually have an area for the data to be written for future use.
Now if you reply again without showing proof of your claims and where I'm wrong, you are the troll.
GO read some of our old posts where I have already explained this, or show up at the WQA show in Florida, I may be putting on a training seminar there. Or I have a large and free training seminar I am putting on in May in Texas, California in June, Florida in July, and a couple more still to be scheduled later this year. Send me a PM and I will give you the dates and times.
Or read below, but I as I have said earlier, this is a long one that will not be understood by you so why am I bothering, you will disagree with it no matter what I or anyone else write.
A twin alternating softener will give 24/7 100% system efficiency. The softener is also soft water regenerated allowing for the water used during the regeneration to be offset in the higher capacity of the regenerated tank. A single tank system will have a "reserve" capacity either manually added or algorithmically controlled by modern electronics. This reserve is lost capacity. Extending system regenerations to not more than every 7 days will minimize this lost capacity. Anything beyond 7 days and the efficiency gains become minimal but not incalculable. Twin alternating systems are designed to use 100% of their rated capacity prior to regenerating so no reserves are calculated into the system. Maximum flow rates need to be calculated with the regeneration backwash and fast rinse flows taken into consideration. A systems total available flow can be slightly lower due to this. A common system size of 10x54 may have a system peak flow of 18 GPM, this will be reduced to approximately 15.6 gpm since 2.4 gpm is used for the backwash cycles. The brine and rinse cycle is less than .75 GPM and therefore is rarely a concern. Some people have tried to falsely claim that the twin alternating systems use soft water during the regeneration and therefore the capacity needs to be calculated. This is a common misconception from people who do not understand the basics of water treatment. When have you ever calculated a systems capacity, and then took off the final rinse water from the systems capacity? This is actually done on some TDS compensated charts that many of the commercial companies use for larger capacity systems where even slight losses of efficiency can add up to a significant cost increase. Rarely does a residential application need to be so carefully controlled since the systems are usually slightly compensated during programming anyways and the very slight loss of efficiency adds up to less than a bag of salt per year or approximately $6. A twin alternating unit is ideal in a residential application where extremely hard water conditions occur or excessive water usage causes the regeneration to be more often than every 4 days. Very large single tanks can be used to extend regeneration frequency but channeling of the resin becomes a genuine concern for systems that will rarely exceed the systems recommended minimum flow rates. An example of this is a 14" diameter softener has a minimum recommended flow rate of 4+ GPM. If you rarely exceed that rate, you can start to have channeling problems. Also the cost of excessively large equipment can easily exceed the cost of a reasonably sized twin alternating system.
As to water efficiency, the amount of water used should be proportional to the size of the system and the amount of resin. So a twin alternating unit may regenerate daily, but will use the same amount of water (or less due to the lack of lost capacities based on reserves) as a very large system regenerating every third day.
Simple math: Application, 8 people, approximately 70 grains hardness.
twin alternating system regenerating every day 1.5 cu. ft. per tank, no reserve, 2.4 x 10 = 24 gallons backwash, 60 x .25 brine cycle (excluding brine)= 15 gallons, 2.4 x 10 fast rinse 24 gallons, brine fill 4 gallons, total of 62 gallons, annual salt usage 4380 pounds of salt, water usage of 22690 gallons
Single tank, 4 cu. ft regenerating every other day, 25% lost due to reserve. 7x10 backwash = 70 gallons. brine and rinse 60x.75 = 45 gallons, 7x10 fast rinse = 70 gallons, brine fill 11 gallons, total 192 gallons. Annual salt usage 5840 pounds, water usage 35040. This is a typical application
Here is an great short explanation of a twin alternating from this article. http://www.wqpmag.com/search-softener-efficiency
Twin Alternating Systems
Twin alternating systems maintain one unit in service with the other tank in regeneration or standby mode. They are commonly used in applications that require 24/7 soft water. With the ability to regenerate multiple times in a day, they can be used in high-capacity applications with limited space availability. As an immediate regeneration system, the full capacity of each tank is used prior to regeneration. Upfront cost will be higher than a single unit, but the salt and water savings generally take a short time to pay for the increased equipment costs.
Residential applications can obtain the same benefits using a twin alternating system, though a very slight periodic service flow loss may be experienced as some of the incoming water is dedicated to the regeneration process.
Alternating systems can be expanded to include four or more tanks with enhanced capability and productivity. For example, demand-flow initiation is excellent for fluctuating service flow requirements as the number of tanks brought on line is determined by the real-time water demand.
Now all this being said, it can all be considered a non issue if variable brining were a common option, but that too has several minor problems that we can discuss during one of my training seminars. And, if anyone on this site wants me to host a training seminar, I will be offering paid and free training starting mid year, I will post more details when we are ready to launch this program.
Here are a few more writings:
Series 9100 Twin Water Softener
The Series 9100 Twin truly is the ultimate in water softener efficiency. The alternating twin tank design allows you continuous soft water 24 hours a day 7 days a week uninterrupted. And because each tank is used to its full capacity, there is no need for reserve, adding even more efficiency.
There is no timer to set.
Every 9100 Twin is built with full flow 1" valves and distributors. Comes with a choice of either ¾" or 1" pipe connections, and an optional 1" commercial meter that increases flow rates up to 24 GPM.
Adjustable cycle times allow minimal water usage.
An optional single lever by-pass valve allows an easy way to bypass the system and provides a simple disconnect.
The five cycle 9100 Twin Series valve is motor driven - no solenoids or diaphragms to stick or hang up. This is the most reliable system for consistent performance.
Separate Salt Tank
The separate salt tank design protects controls from the harsh effects of salt and water that attack conventional control systems.
Due to the twin tank design, the 9100 Twin Series is versatile enough for tough residential applications, as well as for small commercial applications. Choice of salt tank sizes to fit most any space requirements.
Solve your water problems with the “ULTIMATE TWIN” fully automatic softener.
Only an alternating twin tank system such as KRUDICO’S ULTIMATE models can ensure continuous soft water twenty-four hours a day-everyday. Salt and regeneration water are used only in direct proportion to the water that has been conditioned, giving minimum operation costs. Saves on soap, keeps fixtures and tableware shining and spotless, prevents scale build-up which can cause clogging in pipes.
On a twin system, the softener switches tanks then immediately regenerates the tank it just took offline. This allows the system to run each tank all the way to full capacity before switchover. In a single tank system, you must have enough remaining capacity to make it through a full day of the water softener has to regenerate the night before. If you are using a water softener as pre-treatment for a reverse osmosis system a twin alternating model is online 24 hours a day and therefore eliminates the need for pre-treatment lockout on regeneration
In my 25 years you are the only person who I recall that has ever tried to claim a single tank softener uses less salt and water than a twin alternating. This is why training, certifications, licensing etc is so important, otherwise anyone with an internet connection can make false and misleading claims. Now if you want to say that a twin alternating system is overkill compared to the potential salt and water savings in most residential applications I will heartily agree with you. But in those applications where regeneration frequency starts to get to the 4 or less days between regenerations without going to excessively large equipment, a twin alternating system should be considered. Why else do you think that the vast majority of commercial systems are now twin, tri, or quad system designs. The days of the single tank large commercial units are basically gone. I only stock a few HWBP 2900 and 3900 valve, the vast majority of our valves in stock are set up for twin to quad applications with NHWBP lower pistons.
I cant wait to see your response, with 50 quotes taken out of context, and you making a silly point that makes no sense, but I am expecting it so like I said earlier, you ignorance rarely surprises me anymore.
Here again we are talking residential softening.... and off you go into everything about you and what you are gong to do where etc. etc. and then off into commercial/industrial....
I have said that with a twin tank softener, there is an amount of programed capacity (and the salt it takes to create it) used to regenerate each tank of a twin tank softener that equates to the reserve of a regular softener. Programing takes the number of gallons of regeneration water used per tank times the gpg compensated hardness and subtract those gallons from the total number of gallons the regenerated capacity you develop from the lbs of salt needed based on the cuft volume of resin you have.
You, dittodude say 25% for the reserve in a regular softener... I say one day's water use (gals/person/day) for the household and you use 70 or more gallons/person/day where I say 60 gals/person//day. You say the twin uses 100% of its capacity and that the reserve in the regular softener is wasted.
I relate that to you running your vehicle out of fuel and then refueling which no one does because we don't want to deal with running out so we refuel before the engine runs out of fuel and strands us somewhere. Now listening to your illogical claim, you must think the fuel in the tank is wasted if we don't run the tank dry before refueling, but I'll bet you don't do that, you refuel like all the rest of us so you aren't stranded somewhere. The regular softener programed with the same volume of resin and amount of salt to regenerate the same K of capacity has the same salt efficiency as the twin.
Here is the instructions out of the Fleck manual;
3. Setting the gallon wheel. Knowing the amount of resin in each tank and the salt setting per Regeneration, calculate the gallons available, using the following capacities as a guide: (capacity per ft3 x ft3 of resin per tank) = gallons available compensated hardness of H2O
NOTE: Based on tank size: More resin increases capacity, less resin decreases capacity. More salt increases capacity, less salt decreases capacity.
Example: Tank Diameter = 16” Compensated Hardness = 35 grains per gallon (tested sample) ft Resin (based on flow rate) = 4 lbs of Salt = 8 Capacity per ft 3 = 24,000 (24,000 x 4 ft 3 of resin per tank) = 2,740 gallons available before regeneration 35 grains
3 DO NOT SET THIS FIGURE - GO TO STEP 4
— Because the control valve regenerates with soft water from the other tank, subtract the water used for regeneration. Take each regeneration cycle and calculate the water used.
Example: Unit is set for a 16” diameter tank with 4 ft3 of resin and salted at 8 lbs. per ft3, 7 gpm backwash, #3 injector, 1.0 gpm brine refill, and 60 psi and timer set for 10 min. backwash, 60 min. brine and rinse, 10 min. rapid rinse, 10 min. brine tank fill. Backwash 10 minutes x 7.0 gpm = 70.0 gallons Brine and Rinse 60 minutes x 1.0 gpm = 60.0 gallons
Rapid Rinse 10 minutes x 7.0 gpm = 70.0 gallons Brine Tank Fill 10 minutes x 1.0 gpm = 10.0 gallons Total regeneration Water = 210.0 gallons
With the 2740 gallons available calculated in Step 3, subtract the Regeneration water used from the total water available.
2740 gallons available - 210 gallons used = 2530 gallons (in Regeneration, Step 4)
That is copied from page 9 in the Fleck 9000/9100/9500 Service manual at the links below and is proof of what I have been saying. The first link requires you to click on the 9100 Service Manual 40944 link in the Related Items box on that page. My browser or Fleck's site doesn't allow me to view the .pdf file without downloading the manual. The second link downloads the manual.
You are missing the main premise, you are supposed to deduct the capacity from the last half of the brine and rinse cyce and the fast rinse cycle from a standard softener regeneration. Also the lost capacity due to a required reserve does not exist on a twin alternating system. The soft water used to regenerate the tank does not need to be deducted from the systems capacity since their is a zero net loss, unless you want to argue the 24 gallons used for backwash, but that would be a real stretch. Like I said, you will argue with a wall given the chance.
The concept is simply to difficult for you to understand, that is ok. You are welcome to come to some of my training seminars later this year. I also offer consulting and private training seminars for only $900 per day plus travel expenses. I will be posting a schedule of events, but not until after the WQA trade show in Florida, and the carwash show in Chicago. After that, we go into our training seminar season. One hour of the 8 hour seminar is usually dedicated to twin, tri, and quadplex applications including residential and commercial. We go into detail about soft water regen vs hard water regen, advantages, application etc. There is simply no need for you to continue trying to argue your point, you are not able to comprehend the concept. If you want to have some real fun, I will be doing a seminar in the UK in October, and it is an open training for licensed water treatment companies, oops wait, you dont beleive in licenses. maybe you could get one before then.
Last edited by ditttohead; 02-03-2014 at 10:24 AM.
You are acting like some politicians from California so, I will tell Derek about a 4 cuft regular softener programed for his daily water use of 7 people * 60 gals/person/day 420 gals * 25 gpg hardness = 10500 grains/day * 8 days = 84K of the max K of a 4 cuft of 120K @4 * 15lbs = 60lbs. Then 84,000/3333 grains per lb salt efficiency = 25.2 lbs (rounded to 26) per regeneration, which would be based on 84,000 - a reserve of 10,500 = 73500 rounded to 74000. 74000/25 gpg = 2960 gallons on the meter. Or, 84000/25 gpg = 3360 - 420 = 2940 gallons. I would use the 2940 gallons.
If he goes into lets say a 2 cuft (each tank) twin with 3333 grains per lbs salt efficiency, he will regenerate each tank with 12 lbs (40K 3333 grains per lb) at least once and that means 24 lbs and 80K before subtracting his water to regenerate each tank but, On an annual basis it looks like the 4 cuft regular softener would save a 100 lbs of salt per year.when we do (I have not done the math so my guess is), he will only get about 3 days per tank (6 days total; about 1550 gallons between regenerations) instead of the 7 days (2940 gallons) with a 4 cuft regular softener with 25 lbs of salt.
On an annual basis it looks like the 4 cuft regular softener would save a 100 lbs of salt per year; or the 2.0 cuft would use a 100 lbs more a year.
Now if anyone disagrees, do the math to show me the error of my ways.