Filox Iron Filter Installation Question

This is in regard to the installation of a Fleck 7000SXT on a 12x52 tank whole house iron filter with Filox. The tank area is .78SF and I believe the recommended flowrate is 15GPM per SF, so I've set it up with a 1" backwash line and a Drain Line Flow Control button set at 12GPM with a daily backwash and rinse of 10min/10min. This house has a mild, but annoying iron problem of 1.5PPM. Since this is my first Filox installation and the media is very heavy I wanted to get the opinions of experts on whether this setup is correct to prevent fouling of the media down the road. Also, this house has a well with a 220VAC pump capable of high flow rate (greater that 20gpm), but like most wells around here it has a pressure tank. I know that when I install this system the flow rate will vary as the pressure in the tank cycles. Should I increase the backflow period to accommodate the presence of a pressure tank?

VERY MUCH APPRECIATE YOUR SAGE ADVICE!!!

Filox should be backwashed at flow rates that vary with temperature, not pressure. The Fleck DLFC button will adjust to be fairly accurate even in varying pressures. We set Filox systems at 20+ GPM per square foot. I would bump it up to 15 GPM since your pump can handle it. The frequency can probably be adjusted to less, 2-3 days between backwashes. The Fast Rinse can also be adjusted down considerably, especially considering the higher DLFC flow rate. I would recommend less than 5 minutes for the fast rinse cycle.

Sounds like you did your research,

Wow dittohead... that's a great response. I did see the temperature sensitivity to the backwash flowrate (substantially different), but this is a very deep well and the water temperature doesn't vary that much year round. I'll bump up the flowrate to 15 GPM per your recommendation and set the rinse time to 5 minutes. What do you recommend for the backwash time? Is 10 minutes sufficient considering the presence of the pressure tank and the fact the flowrate will vary? I'm thinking to increase the backwash time (15-20 minutes), especially if I increase the duty cycle to every other day. Unfortunately I have a black tank... I wish it were natural so I could backlight it and see how well the bed is lifting.

THANKS AGAIN!!

Filox barely moves during backwash, not like resin does. Notice the backwash expansion amount even at these higher flows is as low as 10%. Backwash flow rate is not based on pressure, assuming you can maintain 30 PSI, the flow control on these valves regulate the flow rate with a button that "collapses" at higher pressure. This allows a fairly consistent amount of water to flow through the button regardless of water pressure. 10 minutes should be just fine, but if you dont mind the extra electrical use and wear on the pump (minimal but measurable), then more frequent, and longer backwashes are always a good idea on Filox. Many of our customers do every third day, 10 min backwash, 3 minute fast rinse for many years, but these guys know their water in their region. Hope this helps!

Terrific Dittohead. I'll hook everything up as you suggest tomorrow and report back. The pressure tank cycles between 35-65psi, so the pressure should be ample. For some reason iron filters are an oddity in this area (Chesapeake Bay). Most homes have iron in the well, but the common rule is to treat the iron and hard water with salt systems. This well does not produce hard water and modest iron levels, so I couldn't see subjecting the owners to a constant hauling of salt bags and opted for the iron filter route. I think Filox will do great in this application.

I feel a lot better getting some smarts from someone who knows this business a lot better than I do - thanks!

Your customer will do better if the differential on the pressure switch is 20 lbs instead of the 30 lbs it is now; 45-65 instead of 35-65. That will provide them with a 40 psi average pressure and they won't notice the pressure swing as they probably are now.

Also, you say the pump is putting out 20+ gpm. How was that established? I ask because that is way higher than a normal sized private well pump will do?
'

First off - thanks for the help with this - it was timely and right on point!

I checked on the well pump and it's a 1.5hp Red Jacket 20G which is listed as pumping around 18GPM. I didn't check the actual flowrate because the spigots are on 1/2" lines. Pressure and flowrate don't seem to be a problem in this house.

I fired up the iron filter and it seems to be performing smoothly. I installed a 1" drain line control valve with a 14GPM button. I adjusted the differential switch to maintain 45-65 psi in the tank, per Gary Slusser's advice. I set the 7000SXT up for a 15min backwash with a 5 minute rinse every other day since the iron contamination in this well is relatively low and it's a 2 person household with moderate water use. You can notice the variation in flowrate as the pressure tank cycles, but it sounds like a very vigorous backwash (which this was a clear tank instead of being painted black). Seems to be good to go and hopefully a good cleaning of the media to prevent clogging.

Cheers
TY

18gpm at what depth? Don't seem to be a problem doesn't mean a whole lot. Filox needs high flow rates and you really need to know what that rate is coming out of the pressure tank. checking it at the sillcocks won't tell you much either because they restrict the crap out of the flow.

traderyoda said:

First off - thanks for the help with this - it was timely and right on point!

I checked on the well pump and it's a 1.5hp Red Jacket 20G which is listed as pumping around 18GPM. I didn't check the actual flowrate because the spigots are on 1/2" lines. Pressure and flowrate don't seem to be a problem in this house.

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There should be a tee on the pressure tank with a 1/2" or 3/4" boiler drain valve. Use it to get a fair idea what gpm you have. And if you are going to be working on private well water, get yourself a flow gauge and rig it up with a pressure gauge and stop valve to be able to actually measure flow at the average psi that the pump is operating at.

The pump being a 20 gpm should be delivering 20 gpm at its rated water depth. You find that info on the pump chart for the specific pump (hp and gpm) @ such'n such psi.

traderyoda said:

I fired up the iron filter and it seems to be performing smoothly. I installed a 1" drain line control valve with a 14GPM button. I adjusted the differential switch to maintain 45-65 psi in the tank, per Gary Slusser's advice.

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Part of changing the pressure range of the pressure switch is adjusting the captive air pressure in the pressure tank. You must do that with no water in it.

The air pressure has to be 1 psi less than the pressure switch setting to turn the pump on. I.E. 45/65 gets 44 psi of air pressure with no water in the pressure tank.

If you use anything that heats the air as you add air to the pressure tank, when you turn on the water it will cool the air and that reduces the air pressure, So 1 psi less than the cut in pressure setting, with no water in the tank (or you don't get the proper volume of air).

traderyoda said:

I set the 7000SXT up for a 15min backwash with a 5 minute rinse every other day since the iron contamination in this well is relatively low and it's a 2 person household with moderate water use.

You can notice the variation in flowrate as the pressure tank cycles, but it sounds like a very vigorous backwash (which this was a clear tank instead of being painted black). Seems to be good to go and hopefully a good cleaning of the media to prevent clogging.

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You probably didn't adjust the air pressure in the pressure tank.

You'd think the "professionals" here would have mentioned the pump gpm, the possibility of running the well dry during backwashing or with the frequency of backwashes you mention. And then that the family size, the amount of iron and the size of the filter do not require backwashing every other night....

Also, where is the drain water going and will it be OK with the volume of water based on your DLFC, drain line ID and the length of time you have it flowing?

The professionals here read your post and decided that it was sufficient to cover the topic but if you are looking for validation I hereby second the motion for the OP to be sure of his flow and well conditions. All in favor say Aye, Aye, the Aye's have it, motion carried.

Merry Christmas Gary.

Sounds like someone has never worked with Filox or Pyrolox.

And Aye

The pressure rating I quoted (18GPM) was based on the well pumps performance chart for a 60ft. lift... I don't necessarily believe it, but the pump's advertised capacity suggests it should be enough to work with this iron filter. It does seem to put it out!

There is a spigot on the pressure tank (which holds 44 gals, by the way). I hooked it up to a short length of hose and a large bucket and got just under 9 GPM, but the spigot is 1/2" so I'm not sure that means much. The line running from the pressure tank is a short run of 1" PVC - a line that size can handle 30+ GPM, so there is no physical limitation to moving a lot of water to the filter. I don't think I need to worry about the well pump. The fact that the pressure tank cycles indicates that the pump is capable of handling the flowrate through the iron filter during backwash AND repressurizing the tank - if the pump was insufficient it couldn't handle both jobs. I timed the tank cycles - it cycles every 80 seconds during the backwash. A 20psi pressure drop in this tank removes approximately 18 gallons - 18 gallons in 80 seconds = 13.5 gal/min. That seems a little low, but pretty close for a Filox system with 2 cu ft. of media in a 12" tank.

Everything I've read about Filox says give this media a high flow rate and keep it backwashed frequently. I read a few horror stories about clogged media from insufficient backwashing, and man is this stuff expensive to replace... like $150 per 1/2 cu ft. bag! I really don't like the idea of running this much water down the drain (by the way, the line from the DLFC fitting is 1" PVC running 6' to a P-trap and air gap then into a 6" PVC drain out to public sewer), but iron build-up is a much bigger problem. So far the drain line and sewer seem to be handling the backwash without any complaining. I followed Dittoheads suggestions for the duration of the backwash and rinse (15/5) - they seem like very good and conservative numbers.

I'm going to return and set up the pressure tank the right way - drain it, check/set pressure, let it stabilize, refill, and check the limits again - thanks for setting me straight on that Gary Slusser.

The filter is doing it's job. I'll post a picture of a white jacuzzi filled up before and after the installation. This well is only 1.5PPM iron, but what a difference it makes in water color when you remove it.

THANKS AGAIN FOR ALL THE GREAT HELP - I hope this exchange helps other as well!

A 44 gallon pressure tank set for 45/65 has a draw down of ~ 12 gallons or less--NOT 18 gallons.

Here is a link to specs for the Well-X-Trol brand which has one of the better draw down specs:

http://www.aquascience.net/amtrol-pressure-tanks/

When you do computations based on the cycle time with the backwash going you have to factor in the fact that 14 gpm is flowing while the pump is trying to refill the pressure tank.

So if, for example, it took 40 seconds for the pressure tank to refill from 45 to 65 psi while the filox filter is in backwash and drawing 14 gpm and the tank drawdown is 12 gallons the well pump output would be 12 gpm /.66 +14 gpm = ~ 32 gpm

To dittohead in post # 11.

I think you don't know what you are talking about.

For 20 years I was a local dealer serving 6-8 counties in central PA and 99% of my customers were on their own well with some on small community wells. For most of those years I also did well/pump work.

In my early days I sold Pyrolox filters (backwashed and regenerated with chlorinated water), then I found better ways to fix the problems Pyrolox etc. were used for and I serviced many that others sold along with many greensand filters others sold.

Based on your posts here it seems to me that you are seriously lacking experience with treating residential and small commercial well water. Most dealers and plumbers are also.

Bob999... apologies, I was a little sloppy with the numbers and my explanation - I was going off the actual pressure gage on the tank and the actual tank capacity. I haven't adjusted the pressure tank properly so the pressure differential is closer to 27 psi than the 20 psi recommended by Gary Slusser - I need to get on that. Plus the 44 gal tank actually holds 47.5 gallons. When I worked it out I got around 18 gallons. When I set it up right I'm sure to get less drawdown volume, but that's okay if the pumps doing its job. As for the flowrate being diminished during repressurization of the tank I disagree - you're assuming a constant flow rate from the pump and that's not what I'm seeing. I put an ammeter on the pump line and when the tank cycles the pumps draws significantly more current, so it's stepping up the flowrate. There's undoubtedly some reduction in flowrate going to the filter, but not much.

Gary - if this helps, the media I used was Matt-son Filox-R and the recommendation is 11.9 GPM for this size tank at water temps at or below 60F. Several other sites recommend higher flow rates. But opinions seem to vary wildly about the backwash/rinse frequency and duration. Very few people recommend taking Filox beyond an 'every other day' backwash, and a lot of folks claim daily is the only way to go. All of you guys know a lot more about this than I do so I'm in listening mode.

I can't imagine a house with a more robust well pump, so I wonder how anyone backwashes Filox successfully if this setup doesn't have enough juice!?

Sounds like you have done your research and are on the same page as everybody else in the industry and the world... -1. Every other day should be adequate, many people use that water for irrigation so the water is not "wasted". Filox-R, Pyrolox, etc should be backwashed according to the manufacturers recommendations, but the water temperature is often neglected to be considered. For many medias, water temperature is not as critical. For Filox/Pyrolox, it is a very important part of the calculation. Congrats on a successful install.

Regarding smaller pumps handling Filox, it is common to use 2 smaller systems so the regeneration backwash rates can be accomodated.

traderyoda said:

As for the flowrate being diminished during repressurization of the tank I disagree - you're assuming a constant flow rate from the pump and that's not what I'm seeing. I put an ammeter on the pump line and when the tank cycles the pumps draws significantly more current, so it's stepping up the flowrate. There's undoubtedly some reduction in flowrate going to the filter, but not much.

Click to expand...

1. I don't think I said anything about flowrate being diminished during repressurization.

2. I don't think I am assuming a constant flow rate "from the pump"--I do think I am assuming a constant flow rate to the backwashing filter equal to the flow control button rating but other than that the rates in the sample calculation are average flow rates.

3. I think the variation you see in current to the pump is the result of varying pressure as the pressure tank cycles between the low pressure cut in and the high pressure cut off. I believe that flow from the well pump does diminish as the pressure in the pressure tank rises.

4. When you say the "tank cycles - it cycles every 80 seconds during the backwash" what is the time interval measuring--pump on to pump off or pump on to pump on?

As a final point--it seems you have plenty of pump capacity to backwash at 14 gallons per minute. As you said the fact that the pump is able to refill the pressure tank during a backwash indicates the pump output is greater than 14 gpm. I was only trying to point out that I didn't believe the calculation procedure you used to determine AVERAGE pump output during a pressure tank refill was correct and to provide you with the correct procedure.

Traderyoda... dittohead says I know nothing about this stuff and he hasn't said a word to correct any of your assumptions about the well, pump or pressure tank and its ability to successfully backwash heavy minerals except to say all's well but... two filters would be better.

If I'm understanding you, that 47 gallons is greatly reduced by the volume of captive air that becomes compressed air when the pump is turned on. Usually that volume amounts to about 60-70% of that 47 gal tank and if it is an air over water tank, such as a galvanized tank, it can be more than 70%.

dittohead needs to expand his thinking out of his southern California climate and think about the rest of the continent. Or at least the 80%+/- part of the US where well water temps are consistently below 50f. And that irrigation doesn't work in that area for about 6-9 months a year and that for many months the temp is below freezing. So there has to be another place the drain line water has to go than outside above ground or even below ground but above the frost line.

Usually that is into an onsite septic system and in many cases a sand mound type. Your 14 gpm for 15 minutes is a lot of water and personally I would not want that much going into my septic system, and then every other night. dittohead seems to think that isn't a problem but your customer may differ and assume incorrectly that you know how to protect their best interests.

Depending on the water level depth in the well, that pump may not being putting out 14 gpm for the 10 minutes of backwash and then another 5 minutes of rinse. If so then your Filox fails. And you are looking at this in the fall and don't know how things will work in a drought so...

What I would want to know, and was capable of determining when I was a local dealer is, how deep is the well, how far down to the water level?

Bob999 - I see your points. The 80 seconds I measured (before really addressing the need to adjust the pressure tank per Gary Slusser's recommendation) was from pump off to pump on. When I get back over there I'm going to properly adjust the pressure tank, redo my calculations, and see how it operates. The other thing I'm going to do is to disconnect the backwash line (there's a 1" PVC union in the line) and test the actual flowrate during a backwash cycle - then I'll know without any question what sort of rate I'm getting through there.

Gary Slusser - this house is on the waterfront of the Chesapeake Bay and is on well, but with public sewer. The owner directed the plumber to install a 6" drain line to the sewer tie-in. In this case the backwash is helping to keep the drain clean and not much else. The well is down 340 ft. and the water is sitting at 58' according to the well report and the pump installers closeout sheet. I'm pretty sure I'm getting enough flowrate... I sure hope so because there's not much more I can do - I put the correct size button in the DLFC port, ensured I had a short run to the filter, installed a 1" drain line, etc. If I were doing this again I would evaluate the wisdom of using two smaller tanks. If I can confirm the backwash rate... and I will... I might have a good solution though; one that will last a long time and solve a perplexing problem for the owner.

Dittohead's comments about frequency of backwash are consistent with what I heard pretty much across the board. The folks at Fleck (this is a Fleck 7000SXT valve) and at Matt-son insisted on 12 GPM and waiting no longer than every other day to backwash. So I have it set now for 15min backwash/5 min rinse every other day. I bumped up the button to 14GPM based on Dittohead's recommendation. I'm not too worried about lifting the bed and dumping material out during backwash because from everything I've read this media just doesn't move very much during backwash - the little bit of extra flowrate can only help.

Your note about being worried about using this much water is something very much on my mind. This past summer was absolutely brutal and though we didn't get a drought ban on water usage, if this kind of heat keeps up I'd be worried about a lot of wells drying up. The homeowners are frugal users of water, BUT they did just install an irrigation system having a drip side and a pressure side with large garden areas. The house is equipped with rainwater capture and recirculation systems, but in the summertime the wellpump really cranks when the irrigation system come on - it's all plumbed with 1" lines. You're right about water temps - this water never gets above 45 degrees. Temperature does determine the backwash flowrate, but at these temperatures 12GPM is what's recommended.

I've attached a before and after picture of the water color, shown with a few inches in a white jacuzzi - the iron filter seems to be doing its job.

You guys have been terrific help on this project and I'm very grateful!

That's nice looking bath water indeed