Backwashing carbon filter?

[Cristian]

Hi all, we recently bought a house out in the country that's on well water. We have not yet moved in, as I am doing lots of remodeling first.

The previous owners were paying something like $85/mo. for a miserable old Culligan unit that they had set up out in the middle of the backyard by the well head with a tarp thrown over it. I had the very pleasant and professional Culligan folks come and remove their unit.

In preparation for buying a new softener setup, I've been scouring the 'net for info, and I seem to be getting more confused the more I research.

I had the water tested and hardness is 15 grains, and 4 ppm iron. We have three adults and one 5 year old in the household. From my primitive calculations, it looks like something on the order of 48k unit would work, and would handle the increased water use as the kid gets older. I'd like to get a smaller unit, like a 32k, but I just didn't want to get one too small.

My real concern here is, while speaking with some folks at neighboring properties, I was told that the water over the past decade or so has shown an increase in contaminants like nitrates and pesticides. I was thinking of putting in one of those fancy backwashing (is the catalytic type better?) carbon filters after the softener, to maybe suck up some of that stuff. But it looks like unless I get something monstrous, like on the order of 4 cu. ft., our water flow will be something like a miserable 4 gallons a minute. I'm not stuck on this particular setup, I'm just interested in filtering out as much as possible before it gets into the house.

I'd really appreciate any advice, comments, remarks or anything else on whether I'm on the right track or whether I may want to consider something different.

- Cristian

 

[Reach4]

I had the water tested and hardness is 15 grains, and 4 ppm iron. We have three adults and one 5 year old in the household.

Given your numbers are not showing decimal points, I would get a lab test for your raw water. I like kit 90 from http://www.karlabs.com/watertestkit/

1.5 cuft would be OK if your iron filter gets all of your iron out.

. I was thinking of putting in one of those fancy backwashing (is the catalytic type better?) carbon filters after the softener, to maybe suck up some of that stuff.

GAC would not work, and generic "catalytic carbon" may not work. My iron+H2S backwashing filter uses Centaur Carbon, a special carbon made from bituminous coal by Calgon. My iron is about 10% of yours, so I don't know how it would do for you. Katalox Light would be worth considering. I suspect you have read about that during your seaches. You might or might not need an injection of an oxidant such as chlorine bleach or H2O2 before. I don't know about the sizing either. What backwashing GPM do you have available?

You could also consider chemical injection and letting the water go into a contact/settling tank with a blowdown port to let you drain off the precipitate.

 

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[Cristian]

Several months ago, I actually had the water tested at a place called Water Shed in Deland, FL and the results were:

iron 3.95
salts 321
hardness 254.

That's all the info I got from the old guy. I've never had water tested before, and at the time I thought that was all there was to it. But I now see people talking about all kinds of stuff they found out when they had their water tested and I'm wondering, aren't the results of water tested at an actual lab supposed to be a little more comprehensive than what I got?

 

[SuperGreg]

That's pretty basic - not even pH! Here is a sample report you would get from KAR labs: https://www.karlabs.com/watertestkit/example-reports/kit90-example-report.pdf

I used a local lab to run my tests and I got something similar, but KAR is much cheaper so I am going to try them out. I sent my original water test results to cleanwaterstore.com and they recommended filters to take care of my water issues. Now I just want to test the treated water and make sure it all looks good.

 

[Cristian]

That's pretty basic - not even pH! Here is a sample report you would get from KAR labs: https://www.karlabs.com/watertestkit/example-reports/kit90-example-report.pdf

I used a local lab to run my tests and I got something similar, but KAR is much cheaper so I am going to try them out. I sent my original water test results to cleanwaterstore.com and they recommended filters to take care of my water issues. Now I just want to test the treated water and make sure it all looks good.

Holy moly. That's the kind of test I thought I was getting with watershed. I'm gonna order one asap. Thank you so much for the heads up on this!

 

[ditttohead]

It would be a bad idea to use softening for iron reduction in his application. Without a comprehensive water test, any advice would be almost silly since their are so many variables. Post the water report as soon as you complete and I am sure we can come up with a fairly simple and effective solution. FYI, nitrates are not removed with carbon. We use a specialized selective cation resin that is regenerated nearly identical to a softener. Some organic chemicals and pesticides can be reduced with a properly sized carbon system.

 

[Cristian]

Would it be safe to assume that the regular old softener resin is fine for removing my 4 ppm of iron, or is there a different or better resin I can use in the softener? The previous owner had a prefilter that was full of nasty brown stuff that I assume was ferric iron, so I guess I'll need one of them too.. (Sorry dittohead I think we overlapped here.)

 

[Cristian]

Hi guys, I called the place I had my water tested at and had the crusty old guy email me the results. All are in mg/L :

Iron 3.95
Hydrogen Sulfide N/A
Total Dissolved Solids 321
Tannins <0.1
pH 7.05
Hardness 254
Chloride 33
Nitrate 0.12
Nitrite <0.011
Lead 0.001

E. Coli absent
Coliform absent

Is this enough to get an idea for the system I need? I'll go ahead and do the Kar thing if necessary, I was just hoping to save the time and get started collecting the components. Thanks for any help on this!

 

[SuperGreg]

I'm pretty sure you're going to need an iron filter for that amount of iron.

 

[Cristian]

My prob is I don't know enough about this biz to know if that 3.95 means ferric iron, ferrite or both. But the prefilter the previous owner had installed was full of brown stuff because he obviously never did any kind of maintenance. After seeing his filter, I had pretty much resigned myself to the fact that one would be necessary. Just wondering if that and a softener is all I need.

 

[Reach4]

My prob is I don't know enough about this biz to know if that 3.95 means ferric iron, ferrite or both. But the prefilter the previous owner had installed was full of brown stuff because he obviously never did any kind of maintenance.

Ferrous would settle out. Your test shows ferric.

After seeing his filter, I had pretty much resigned myself to the fact that one would be necessary. Just wondering if that and a softener is all I need.

People have successfully used a softener to handle your level of iron. You would set up the softener as if you had 35 grains of hardness. It takes a lot more salt. More importantly, it takes extra cleaning and treatment. I suggest you search for "iron out" in the older posts in this forum. You would want to use a Rescare or Res-clean dispenser, and/or special iron-handling salt.

You would want to have the softener regenerate every 3 days, so you would size the softener more like you would with only 15 grains without the iron.

I suggest you try to leave room for an iron treatment system that you could add in the future.

 

[Cristian]

I have been researching the Katalox Light you recommended in a previous reply, and it does indeed look like what I need. Do you think something like a 1.5 cu ft backwashable filter of KL would take enough load off the softener to let it do its job? I have no problem getting a permanent solution for the iron right off the bat, since we're not even living in the house yet. I also read about something called "Filox." Maybe a better choice? This is confusing.

 

[Reach4]

I have been researching the Katalox Light you recommended in a previous reply, and it does indeed look like what I need. Do you think something like a 1.5 cu ft backwashable filter of KL would take enough load off the softener to let it do its job? I have no problem getting a permanent solution for the iron right off the bat, since we're not even living in the house yet. I also read about something called "Filox." Maybe a better choice? This is confusing.

I am not sure of the ideal sizing -- whether 1.5 is enough, or bigger is warranted. The thing that bigger lets you do is to run more GPM thru while maintaining a particular reduction in iron. We can be confident that 1.5 would be much better than letting the softener carry the load.

Filox is an older media. It takes a lot more backwashing rate. Part of sizing and media selection is to know how many GPM your well pump can deliver. For 1.5 cubic ft of KL in a 10 inch diameter tank in Florida, you would want about 8 or maybe even 9 GPM for the backwash. Warmer water needs a higher rate. A 12 or 13 inch tank needs more backwashing. Backwash is normally every third night in the middle of the night. If you could only deliver 5 GPM of backwash, some other solution might fit better.

 

[Cristian]

When I was researching the Filox type media, the sheer weight of that stuff caused concern that I wouldn't be able to backwash it. I suppose my next mission is to find out the GPM of my current pump. If my flow turns out to be something miserably low, is it usually just a matter of installing a new, more powerful pump?

 

[Reach4]

When I was researching the Filox type media, the sheer weight of that stuff caused concern that I wouldn't be able to backwash it. I suppose my next mission is to find out the GPM of my current pump. If my flow turns out to be something miserably low, is it usually just a matter of installing a new, more powerful pump?

Maybe. An alternative would be a treatment system, such as chlorine or peroxide injection followed by a contact/settling tank.

You are probably fine with a submersible pump. A nominal 7 GPM submersible can put out 8 or 9 GPM for backwashing typically. An above-ground pump might have similar characteristics in that regard. I don't know.

What do you know about your well and pump?

There are methods to measure your pump flow by measuring the drawdown of your pressure tank, and seeing how quickly it gets refilled. Otherwise, you can open multiple faucets. You have to be careful that you are not partially measuring the pressure tank storage ability while using that method.

 

[Cristian]

1. The only thing I know about the well and pump currently is that it's a submersible pump. I don't even know how to find out anything else about it! But I'll measure the flow tomorrow. I assume all I have to do is measure the water that comes out until the pump goes on, then tie how long the pump runs to replace what was drained out. I'll post my results. Thank you so much for the help so far!

 

[Cristian]

Hi Reach4,
I tested the well pump today, using spigot a few feet away from the well head. I hope that's the right place to test from!
The pressure started out at 65 p.s.i., and the pump came on right around 38-40 p.s.i.
During each of my several tests, the pump always ran for exactly 4 seconds to replace the water, which was only a little more than 1.5 gals per cycle.
The pressure tank is 16" x 45", which I assume is 30 gallons.
I used a 5 gallon bucket to test water volume, and 3 runs of the water before the pump kicked in brought the water to 2" from the rim of the bucket
(I assume that's around 5 gallons, since that's about where the paint level comes to when I get 5 gallons of paint.)
When I open the bib all the way, the pump held 60 p.s.i. continuously.
So, does this mean I can assume my pump flow is around 5/3 x 15 = 15 gpm?

 

[Reach4]

I don't see a flaw in your thinking, but maybe I will rethink later. Another way to calibrate your bucket is to weigh it with water and empty, and do the math. It would seem that you have enough water to support even a larger KL tank.

Your pressure tank is very probably shot. You should set the air precharge to make sure. With a 15 GPM pump, I would like to see a 62 gallon pressure tank.

 

[Cristian]

Today I got a gallon jug and 5 full jugs went up to the line in the 5 gallon bucket filled by 3 drawdowns from the pump. So I guess my previous calculations may have been in error because 5/3 gallons in 4 seconds is more like 25 gpm, which sounds pretty high, but that's what it's pumping.

As for the pressure tank, I have been researching that Cycle Stop valve that uses a little 2 or 3 gallon tank instead of a much larger one. Any disadvantages of going with that setup and avoiding the big pressure tank altogether?

I also noticed some folks use a Fleck 2510 "AIO" valve to aerate the water to help oxidize the iron, but then they say that it tends to put out aerated water. Is this aeration setup anything I should pursue or avoid? I'm just trying to keep things as simple as possible, and will just as soon just get a bigger filter tank if it'll do the same thing without aeration.

As always, all help is really appreciated!

 

[ditttohead]

Katalox light is clinoptilolite coated/impregnated in Filox (simplified but the point is understood I hope). This allows for a similar performance to Filox with the backwash of Clinoptilolite (micro-z, filter ag+, next sand etc...)

Once we get the lab water reports we can make suggestions, I would not recommend doing anything until then. Lets ee whats in the water. I already see a problem with a softener only solution, The ferric iron will coat the resin very quickly or simply pass through it. When using a softener only solution we want a low pH, your pH is on the border, but... KAR labs report, lets get it and well go from there.

As to the 2510AIO... it works but tends to create airy water. This is not that big of a deal, but it can be annoying. H2o2 injection and KL would be the most obvious nearly guaranteed way to get rid of the iron then a simple softener.