Katalox Light raises pH above legal limit

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Reach4

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The only other "treatment" is a Mazzei air injector upstream from the Katalox. I commissioned the Katalox system around 20 Feb and got accurate test a few days after that and again on 30 March
Your system could be the inspiration for those who might want to raise their pH while treating for iron etc. Yours overshoots, but you may have stumbled onto a method/magic that could be helpful. I am confident that WellOff is alert!

Maybe identify the model number of your air injector (or did you and I missed it), and provide other info. What do you do to remove the injected air?
 

WellOff

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Just to add a data point...

I recently ran another test of KL (using a drop-in cartridge, special testing) and my lab results came back showing a pH of 9.5. My pH (raw and treated) tends to be right around 7.0. I'm documenting in this thread: https://terrylove.com/forums/index.php?threads/battles-with-manganese.59540/

Because the test results clearly showed a reduction in Mn, to the point of it being below the secondary MCL for Mn, I'm really leaning toward changing my backwash filter's media to KL. If/when I do so I'll post back on what my pH levels end up at: I likely won't (and hopefully for him) get this done before GeraldP's issue is resolved.
 

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Time permitting, I will try to do some real world testing on KL this Summer re: the pH issue. I have an anti-scale test in the works first that was supposed to be started in January, still haven't got that one started so Summer may be optimistic. :)

Not sure why Watch would say anything other than of course the pH raise is going to occur... the media has been reformulated to lessen the pH rise, this was quite a while ago so this is not a new or unheard of issue. Again, the high pH does not seem to have any negative affect and may simply be a semi artificially high pH as neutralization is extremely easy compare to water that has high pH due to large amount of calcium, magnesium, etc...
 
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I have a property in Scotland which has a water supply from a borehole with around 9ppm Iron and 0.3ppm Mn and a pH of 5.9. I have recently installed a Katalox Light system and this has sorted the Iron and Manganese problem but the pH has rocketed to 9.8 which is above the UK legal limit for drinking water of 9.5. The house is used for holiday letting and I have to get it officially tested and am therefore under pressure to lower the pH below 9.5.

For the last two months I have been trying to get Watch Water to help solve this problem, but just today have finally been told by them that they have only encountered this problem three or four times in the whole world. However in the same breath they tell me that their literature states that it can raise pH up to 10 so I cannot complain!! I neither saw this literature nor was made aware of it before buying the Katalox. They cannot explain satisfactorily why the Katalox has raised the pH so much and have effectively said that their Chemists are not interested in doing so as the problem is so rare and they don't have the time.

Has anyone had any experience of high pH problems with Katalox or has anyone any idea what has caused this and if there is anything I can do to correct it.

Any help would be very gratefully received.

Many thanks in advance.

Gerard


What is the total hardness of the water? Elevated PH levels are documented in this KL manual (http://www.watchwater.com/home/downloads/KL_operation_manual.pdf) due to calcium carbonate undergoing CO2 diffusion which in consequence would elevate the PH relevant to the incoming hardness. This may seem a little backward but in may be more advantageous, in this application, to remove the hardness before the KL filter to prevent the CO2 diffusion process from occurring. Obviously the resin would need to be replaced on a regular basis.

The Water Softener Blog
 
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I have a property in Scotland which has a water supply from a borehole with around 9ppm Iron and 0.3ppm Mn and a pH of 5.9. I have recently installed a Katalox Light system and this has sorted the Iron and Manganese problem but the pH has rocketed to 9.8 which is above the UK legal limit for drinking water of 9.5. The house is used for holiday letting and I have to get it officially tested and am therefore under pressure to lower the pH below 9.5.

For the last two months I have been trying to get Watch Water to help solve this problem, but just today have finally been told by them that they have only encountered this problem three or four times in the whole world. However in the same breath they tell me that their literature states that it can raise pH up to 10 so I cannot complain!! I neither saw this literature nor was made aware of it before buying the Katalox. They cannot explain satisfactorily why the Katalox has raised the pH so much and have effectively said that their Chemists are not interested in doing so as the problem is so rare and they don't have the time.

Has anyone had any experience of high pH problems with Katalox or has anyone any idea what has caused this and if there is anything I can do to correct it.

Any help would be very gratefully received.

Many thanks in advance.

Gerard


What is the total hardness of the water? Elevated PH levels are documented in this KL manual (http://www.watchwater.com/home/downloads/KL_operation_manual.pdf) due to calcium carbonate undergoing CO2 diffusion which in consequence would elevate the PH relevant to the incoming hardness. This may seem a little backward but in may be more advantageous, in this application, to remove the hardness before the KL filter to prevent the CO2 diffusion process from occurring. Obviously the resin would need to be replaced on a regular basis.

The Water Softener Blog
 

Reach4

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This may seem a little backward but in may be more advantageous, in this application, to remove the hardness before the KL filter to prevent the CO2 diffusion process from occurring. Obviously the resin would need to be replaced on a regular basis.
That http://www.watchwater.com/home/downloads/KL_operation_manual.pdf document says "Solution: If there is a noticeable increase in the pH above the normal range, simply repeat points "3", "4" & "5" from the "Installation Basic" section". I interpret steps 3, 4, and 5 to be some extra backwashes with the BW time increased to 30 minutes and waiting at least 35 minutes between the extra backwashes.
 
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That http://www.watchwater.com/home/downloads/KL_operation_manual.pdf document says "Solution: If there is a noticeable increase in the pH above the normal range, simply repeat points "3", "4" & "5" from the "Installation Basic" section". I interpret steps 3, 4, and 5 to be some extra backwashes with the BW time increased to 30 minutes and waiting at least 35 minutes between the extra backwashes.

That does not appear to be working in this application. Removing the hardness before the KL may very well solve this problem. As Dittohead pointed out. Solving difficult water problems often means some experimenting. I would say this instance calls for some experimenting.
 

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The point of using KL is to reduce iron and manganese efficiently. The use of a traditional softener ahead of KL would negate the need for KL and is highly inefficient. If you must have the pH lowered, possibly a simple acetic acid injection (White vinegar) or a weak solutions of hydrochloric acid (Muratic) or sulfuric acid can be used but these are more hazardous and require special handling, or even a citric acid injection.

Have you tried testing the pH change at higher flow rates? Maybe do the water sampling at a much higher than normal flow to get by the test?
 

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Many thanks for all the posts. I’m sorry it has taken me so long to repost and reply. I’ve been up at the house and forgot my laptop charger so couldn’t log in!

As suggested right at the start I went and checked the real backwash rates. When the system was installed some time ago the installer measured the flow to the house to ensure it was sufficient and it came out at around 3cubic meters/hr which equates to around 7 gal/sq ft/min. I took this figure at face value therefore assumed the backwash flow would be greater. However, I’ve had problems for some time now with my old Triplex system and always assumed it was something to do with my water chemistry rather than flow.

When I thought the only answer was to go for a pure MnO2 system I bought a digital flow meter but then I discovered Katalox Light with its reduced backwash rate due to its lightness, I didn’t bother plumbing it in as I assumed the backwash rate would be good and indeed the backwash rate is definitely better than with the old Triplex system. Bad decision!

I’ve just plumbed in the meter and taken the readings. It seems that although the initial flow is nearly 9 gal/sq ft/min, it steadily drops as the pressure vessel deflates until it's down to just over 6.

I now suspect that the original measurements were take whilst the pressure vessel was fully charged and I haven’t appreciated the huge drop in flow once the vessel’s pressure drops. I’m also wondering if much of the problem I was having with my Triplex (US version of Terminator Iron filter systems, I think) system can also be put down to lack of backwash! Altogether a bit of a blow to my pride and confidence. My only saving grace is that none of the professionals who I consulted spotted this either. We all assumed wrongly that the original equipment was adequate – a salutary lesson!

I’m going to have a good think about the next stage – do I want to buy a new pump to fit the tank or downsize the tank to fit the pump. If I’m going to get a new tank should I opt for a Vortech system and try and overkill the backwash?

Gerard
 

Reach4

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I haven't actually measured the backwash flow, but I have measured the flow to the house at just under 3metres/hour which equates to around 13.2US Gal/min. My tank is an 1865 which gives an area of 1.75sq ft. So the house flow rate is around 7.5 gpm/ft2
1.75 sq ft corresponds to 17.91 inch diameter or 454.98 mm. So I deduce that 1865 is 18x65 inches. How much KL do you have in there? Click Inbox.

I’m going to have a good think about the next stage – do I want to buy a new pump to fit the tank or downsize the tank to fit the pump. If I’m going to get a new tank should I opt for a Vortech system and try and overkill the backwash?
When the pressure vessel/tank is empty and the pump starts during backwash, what does the pressure go to? Does the pressure drop below your cut-on pressure for the remainder of the backwash?
 

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Downgrading your tank size would work but would likely require two tanks to get satisfactory results. Upgrading your pump is a better solution assuming your well can handle toe higher flow. How about an atmospheric storage tank? This can offer many benefits at a fairly cheap price.
 

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do I want to buy a new pump to fit the tank or downsize the tank
An iron reduction system is generally sized when possible, to satisfy the usual consumption requirements, as long as the well, pump and plumbing can support the back wash requirements for that size filter. If you were to replace the pump, will the well support a higher flow and recovery rate to support a higher capacity pump?
Perhaps a cistern will be needed to hold a quantity of water from the well, so that a second pump then pumps water from the cistern to the home plumbing.
Alternatively, the current quantity of KL media could be split between two smaller size tanks with 1 additional control valve needed, thereby creating 2 separate systems plumbed in parallel. Each would then be back washed at different times.
Edited to add: Dittohead posted while I was keying my reply.
 

Reach4

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My pump is rated at 5.6cu metres/hr which would give a flow rate of 15gpm/ft2.
If I did this right.... 5.6 m3/hr is 1479.36 gallons per hour, or 24.66 GPM. A pump rating is normally at its design head rather than at zero head. So pumps will often pump more (or less) than their rated flow.

For 13 gallons/ft2, on an 18 inch tank, you need 23 GPM. I suspect it is the Fleck 2750 controller that is the main limiting factor in the backwash. If that is the case, if the pump kicks on during backwash, the pressure would rise. If the pressure continues to fall or stays the same, then the pump and plumbing before the pressure tank would be the limiting factor.
 
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ditttohead

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An iron reduction system is generally sized when possible, to satisfy the usual consumption requirements, as long as the well, pump and plumbing can support the back wash requirements for that size filter. If you were to replace the pump, will the well support a higher flow and recovery rate to support a higher capacity pump?
Perhaps a cistern will be needed to hold a quantity of water from the well, so that a second pump then pumps water from the cistern to the home plumbing.
Alternatively, the current quantity of KL media could be split between two smaller size tanks with 1 additional control valve needed, thereby creating 2 separate systems plumbed in parallel. Each would then be back washed at different times.
Edited to add: Dittohead posted while I was keying my reply.


LOL, your explanation was much better though. :)
 

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I've just got back from another visit to the house and submitted another sample for testing. It seems that everything has changed and those saying the pH problem would eventually self correct are absolutely right! The latest pH reading is 7.8. However this pH correction comes with a huge increase in iron level - up to 0.344 mg/l (up from 0.068 mg/l) and a rise in turbidity to 2.7 NTU from 0.6 NTU. So my pH problem is solved but I'm back to square one with the iron problem. This is exactly the same issue I had with the old Triplex media.

I'm wondering if it's all due to the backwash problem. My rate is approx between 9 - 6 g/min/sq ft instead of 10 - 8g/min/sq ft. Whereas I can see that the backwash rate might delay the dissolving/flushing of fines, I wouldn't have thought this would result in serious clogging of the media. If it does then will the media be "cleaned" by more vigorous backwashes or is it clogged for life!

If it's not all to do with the backwash then could the rise in iron level be due to the lowering in pH and the excellent iron removal earlier was due to the very high pH of 9.8. In which case am I now looking at how to raise the pH rather than lower it!!!

I suspect it is the Fleck 2750 controller that is the main limiting factor in the backwash. If that is the case, if the pump kicks on during backwash, the pressure would rise. If the pressure continues to fall or stays the same, then the pump and plumbing before the pressure tank would be the limiting factor.

I measured the flow of the pump on its own at the pump house rather than at the well head and the rate was a fairly consistent 3.4 m3/hr. This would equate to 8.45 g/min/sq ft for my 1865 tank. Given the venturi system and katalox media etc adding flow resistance I guess that even if the Fleck valve adds some extra resistance the pump is definitely underpowered.

Downgrading your tank size would work but would likely require two tanks to get satisfactory results. Upgrading your pump is a better solution assuming your well can handle toe higher flow. How about an atmospheric storage tank? This can offer many benefits at a fairly cheap price.

An iron reduction system is generally sized when possible, to satisfy the usual consumption requirements, as long as the well, pump and plumbing can support the back wash requirements for that size filter. If you were to replace the pump, will the well support a higher flow and recovery rate to support a higher capacity pump?
Perhaps a cistern will be needed to hold a quantity of water from the well, so that a second pump then pumps water from the cistern to the home plumbing.
Alternatively, the current quantity of KL media could be split between two smaller size tanks with 1 additional control valve needed, thereby creating 2 separate systems plumbed in parallel. Each would then be back washed at different times.
Edited to add: Dittohead posted while I was keying my reply.

I reckon the well will support a much higher flow than I'd ever take. I've run the backwash for 2 hours a couple of times with no problem. Interestingly, though, when doing all the recent test I noticed that after 40 mins doing various tests one after another the lowest pump rate during backwash decreased to 5.4 g/min/sq ft! It was explained to me that this would be due to the well water level dropping thereby increasing the effort needed to pump the water up to the surface and therefore lowering the speed at which it could do so. I'll need to factor that in when I spec a new pump but I don't think I'll run out of water at normal usage.

A storage cistern's a possibility and I'll certainly consider this. Particluarly if I end up needing pH adjusting tanks and possibly a post aeration but pre pH adjustment filtration tank to ensure the pH reducing media does not clog up.

How much KL do you have in there?

When the pressure vessel/tank is empty and the pump starts during backwash, what does the pressure go to? Does the pressure drop below your cut-on pressure for the remainder of the backwash?

I've got 6 cu ft of Katalox in the tank.

Yes, once the pump starts it cannot run the backwash and fill up the pressure vessel and so runs continuously during the rest of the backwash and for a short time after the backwash has finished.

Once again thanks for all the replies!

Gerard
 

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I'm wondering if it's all due to the backwash problem. My rate is approx between 9 - 6 g/min/sq ft instead of 10 - 8g/min/sq ft.
From the Backwash Velocity [m/h] vs. Bed Expansion [%] graph, to get 30% bed expansion I think you would want 23.13 GPM with your 18 inch tank if your water was 20 C / 68 F. For 25% bed expansion if your water temp was 10 C you would want 14.24 gpm. My graph reading and calculations may be off. Message me if you want the crude spreadsheet. If somebody wants a similar table for a different tank diameter, let me know.
Edit: I also made the same table for a 10 inch tank, which is a popular size.
img_2.GIF
 
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Bannerman

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the rate was a fairly consistent 3.4 m3/hr. This would equate to 8.45 g/min/sq ft for my 1865 tank.
As previously stated, I seem to recall Dittohead some time ago specifying just under 14 16 gpm/ft2 being the optimal rate for Katalox Light media, even as that rate is higher than specified by Watch Water. I suspect Dittohead's testing and experience is based upon 50% bed expansion.

As your pH and iron results are drastically different than those previously indicated, was the sample obtained differently this time? Was the test performed on water that had been sitting in the system or was the water permitted to flow for some time prior to obtaining each sample?

If a cistern is chosen, the incoming water could be directed through a spray nozzle located above the cistern's water line. This will induce air into the water which will initiate oxidization within the cistern so that some iron will precipitate out prior to the KL filter.
 
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View attachment 34581
From the Backwash Velocity [m/h] vs. Bed Expansion [%] graph, to get 30% bed expansion I think you would want 23.13 GPM with your 18 inch tank if your water was 20 C / 68 F. View attachment 34582

As previously stated, I seem to recall Dittohead some time ago specifying just under 14 gpm/ft2 being the optimal rate for Katalox Light media, even as that rate is higher than specified by Watch Water. I suspect Dittohead's testing and experience is based upon 50% bed expansion.

I haven't taken the temperature of the water but I suspect it is nearer 10 degrees than 20 as even in winter when the pump house is around 10 degrees the tank feels cold. In summer (and we're very lucky if it gets to 20 degrees here in the highlands) there is always a lot of condensation on the tank when I do backwashes). That means that my backwash starts off okay for 25% expansion but degenerates to substandard pretty soon once the pressure vessel discharges.

I'm not sure if my current set up could cope with a 50% bed expansion as I've only got 30% free space at the top! With 50% the media would be washed out the top during the backwash! From Katalox's chart it looks like my expansion will vary from 27% to 21% at 10 degrees. I'll try and measure the temperature the next time I'm up which will be this weekend.

As your pH and iron results are drastically different than those previously indicated, was the sample obtained differently this time? Was the test performed on water that had been sitting in the system or was the water permitted to flow for some time prior to obtaining each sample?

Interesting thought. I've tested the water using a certified lab three times now:

22 Feb pH 9.8 Fe 79 ug/l Turbidity 0.8 NTU Ca 24mg/l
Sample taken soon after installing the Katalox but after a weekend of backwashing including two sets of 2 hr continuous backwashes and frequent 10 min backwashes. The sample was taken at the pumphouse and just after a full backwash, rinse and then running the water for 5 mins or so to try and ensure the water I tested had been sitting in the system as little as possible.

30 March pH 9.8 Fe 68 ug/l Turbidity 0.6 NTU Ca Not tested
Sample taken from the kitchen tap by the Council Environment tester in the morning at 10 am. I had run the tap for 10 mins or so just before to ensure the water had not been sitting in the pipe between the pump house and kitchen but the water could have been in the Katalox tank since the backwash at 2 am that morning (8 hours).

31 May pH 7.8 Fe 344 ug/l Turbidity 2.7 NTU Ca Results not in yet
Very similar to sample 2, except the sample was take from the pump house after all treatment inc UV filter etc. I did the same short flush to ensure the water was from the Katalox tank which had been sitting there since the 2 am backwash.

So the first sample was "fresh" water that had flowed straight through the system but the second and third samples were taken from water that had probably spent 8 hours in the Katalox media.

I'm still waiting for the Calcium test results on the latest test. If my thoughts are right that the original pH increase is due to the Calcium in the Hydrated Lime the I will expect the Ca result to be substantially lower. Except that nothing seems to go as I expect!!

Gerard
 

Reach4

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If your drain tubing is 1/2 inch~13 mm or 3/4=19mm, maybe you could bump that larger to 1 inch~25mm... Maybe make any fittings more full bore or sweeping rather than restrictive?
I'm afraid my set up doesn't have a DLFC button. It simply pumps through the maximum it can for as long as the timer is set for. The valve is an old Fleck 2750 pre electronic. However it's served me well and I've been through 3 pistons in the 16 years it's been running.
I was reviewing the thread. http://waterpurification.pentair.co...oad/en/2750-downflow-service-manual-42327.pdf lists available DLFCs on page 19 Page 17 shows the location of item 35.

Maybe you meant that the DLFC button has been removed to maximize backwash.
 

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If your drain tubing is 1/2 inch~13 mm or 3/4=19mm, maybe you could bump that larger to 1 inch~25mm... Maybe make any fittings more full bore or sweeping rather than restrictive?

I was reviewing the thread. http://waterpurification.pentair.co...oad/en/2750-downflow-service-manual-42327.pdf lists available DLFCs on page 19 Page 17 shows the location of item 35.

Maybe you meant that the DLFC button has been removed to maximize backwash.

If your drain tubing is 1/2 inch~13 mm or 3/4=19mm, maybe you could bump that larger to 1 inch~25mm... Maybe make any fittings more full bore or sweeping rather than restrictive?

I was reviewing the thread. http://waterpurification.pentair.co...oad/en/2750-downflow-service-manual-42327.pdf lists available DLFCs on page 19 Page 17 shows the location of item 35.

Maybe you meant that the DLFC button has been removed to maximize backwash.

Thanks Reach4 - I'd never realised that this bit on the valve controlled the flow and always thought it was just a straight through bit of brass. I'd wrongly assumed the DLFC would be something I could adjust in situ rather than unscrew and fit another one. Shows how lacking my knowledge is in some areas! Unfortunately I've no idea what size of DLFC it is - see picture. I'll be up at the house at the weekend and Ill have a good look to see if it's got a stamp id on it, or is it just the internal washer that would need changed - in other words is the internal washer the "button" you mention.

Even if this part is not the limiting factor now, if I get a stronger pump as seems likely at the moment I'll have to check this out to make sure it can cope. I'm really glad you pointed this out to me.

Gerard
 

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