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Update on Borehole and Filtering System

Peter Topp

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From my last post on my borehole and filtering sytem I have added some improvements.

1. Added a venturi to oxidize the iron in the water before filtration. I have not added a ozone injector which I have as  I am worried it might damage the rubber, plastic and other parts in the system.

2. Added a run dry protection for my booster pump as this was my weak point in my system when the tank ran dry and damaged my pump twice.

3. Added a auto irrigation and jojo fill controll using plastic 24vac irrigation valves to reduce my municapal water consumption.

I hope this will help someone who plans on a similar or part of my system.


Attahed is the updated diagrams.




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  • 2 months later...

Further Update


After my initial water analysis, the ph was 6.9 in September 2017. I have done futher tests in December 2018. This what I have found.

I initially filtered my primary irrigation  water with 120 micron mesh filter, then a clinobrite media (swimming pool media),  birm media and finally a 120 disc filter. The household side had a further 4 filters, a 10 micron filter, a solid carbon filter, 5 micron filter and a uv light.

This was not good enough as too much dissolved  iron cand solids came through and contaminated the filters quickly ( 1week) and the water tasted awful.

I then deceided in September 2018 to inject ozone 10g/H and air by means of a venturie.

This has been the results after test done in December 2018.

The ph has dropped to 6.2 before filtering and dropped futher to 5.8 after filtering at 24 degrees celcius.

This has firstly due to less clay colloids which were far more concentrated in the newly drilled borehole.

Secondly after filtering the injected air and ozone reduced the ph due to the absorbtion of carbon dioxide in the water.

This effect has led to other problems.

Firstly birm media needs ph of at least 6.9 to work effectively and secondly the low ph is not good for my plumbing.

I now see when I backwash my birm media that it is clear and this shows that it no longer has any filtering effects.

The  primary clinobrite filter media now works well and drops the iron content from about 5mg/l (TDS 20) to about 0.7mg/l (TDS11) at 24 degrees celcius.


I now had to think of something to increase the ph of the water to about 7.5.

There any various methods of increasing the ph and I chosen to use a calcite which is calcium carbonate in pebble form which is slower release. 

This will only be done on the household water side as it is not necessary for irrigation and It is a consumable and will need to be replenished sooner.

I will also remove the birm and fill the vessel with clinobrite.

I have put in 2 more vessels with clinobrite media and  1 for calcite media. Iam hoping the iron (fe) content will drop below 0.3mg/l.

I need to put in a second venturie on the household water side as the flow is less in this line to fill the storage tank and the the primary venturie does not work when it fills the jojo tank and only works for irrigation.

The primary venurie is  20mm. The second one will be a 15mm venturie also joined for ozone injection when the borehole is on.

I will also put in futher big blue filters (3) with carbon and  5 micron filters to improve the taste of the water from thee jojo tank.

I have installed automatic backwash to all ftp vessels (5).

This is a lot of filtering however I need  to be  sure my water is fit for consumption and I do not want to use chlorine injection route in any form.

There can also be anothe complication that the calcite can harden the water however this is not a problem for me as my TDS is 11 before calsite is added.


Clinobrite is an inexppensive media  (<R300 a bag) used in swimming pools and koi ponds. It is made from zeolite and can filter out iron (fe) if it is an oxidized form.

I am almost sure other media like clino-x, turbidex and other trade names or simalar media are also made from zeolite at 3x the price.

If anyone kknows if there is any difference please post it.


Other media like DMI-65 needs  chlorine predose then the chlorine needs to removed after iron removal.

Maddox or greensand need potassium permanganate (condy's crystals) to regenerate or chlorine predose.

I hope to complete this project early in 2019 and will post pictures and results from changes.


Please feel free to comment on any other methods to improve my water quality.

It has been a long and winding road to get to this point.

Peter Topp




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  • 1 month later...


As I promised is the updated diagram of the full borehole water system and some photos.

There is one problem I would like some help with.

With the two venturi's I have installed there is some water leakage back in the silicone pipe after the borehole pump switches off.

My system is under pressure as the valve closes when the borehhole pump switches off. This water has migrated to my ozone generator and damaged it.

I do not think putting  a one way valve will work as the my system is under pressure and it will eventually damage the silicone pipe. The venturi's do have a spring ball stop.

At present  to resolve this problem I have put in a straight brass connector in line with the silicone pipe with a 2.5mm hole in it. This allows the water drain out wiithout affecting the ozone suction into the system. This can be seen in my photo.

If someone has a better solution please post it.

Peter Topp


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  • 1 month later...
  • 2 months later...
  • 1 month later...


To clarify the sediment filters in the big blue.

There are carbon filters in the big blue and they give a large amount of carbon dust when you first use the carbon.

The sediment filters  eliminate this getting into the drinking water.

I did take out 1 solid carbon filter in the feed to the jojo tank as it restricted the flow too much.

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I have made a few more changes to the system which are not to drastic.

Firstly I do not inject ozone any more because the air injected by the venturies is good enough to oxidise all the dissolved iron in the system. If you have a look I have two venturies.

The injection of air into the system from the venturies left me with another problem. When the valves closed after filling the jojo or after irrigation it left the sytem under pressure because there was now air in the system between the valves and  pressure vessels. Water alone is unable to be compressed  This is a problem if you have plastic sediment filters (disc or mesh) as they expand under this pressure and are difficult to open for cleaning purposes and it can also be dangerous.

To overcome this I added a third irrigation valve which is connected under the pvc mesh filter (the incoming side from the borehole pump) and to the waist pipe. This valve has been wired N/O and it will only close when the irrigation or jojo fill is on. 

The great benefit for this is that is cleans my mesh filter every time after use by releasing the pressure and the clean water and air flowing backwards through the filter clears the trapped sediment.  I do not think it will work as well with a disc filter. I have a lot of clay which blocks the filter.

This has reduced my cleaning from once a week to once a month.



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Are you pumping from very deep that you have lots of dissolved iron? Fe2+ ions are soluble in water, Fe3+ which is what you are creating with ozone or air is relatively insoluble and will come out as rust coloured sediment. Usually when the water table is rain fed or shallower it is relatively oxidised, I'm curious why your water is so reduced?

Edited by DeepBass9
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On 2019/08/10 at 1:48 PM, Peter Topp said:

The great benefit for this is that is cleans my mesh filter

Hi Peter,

What size is the mesh filter?

I’ve followed your advice with the Clinobrite but now finds my 1 micron paper filters clog up rapidly with a red iron sediment. The Clinobrite is working better than the Maddox in my opinion.

The current iron content (done for free at Builders) is 0.2 (sample taken from my bathroom). When I had the raw water analyzed initially it was 0.3 from the borehole.

I do back washing on my blue filter but the water coming out is very clear so the iron must be leaving the Clinobrite filter. Is there a product which I can add to the top of the Clinobrite to catch the very small iron particles?

I don't want to back to the 5 micron paper filters as I’ve lost my Paloma gas geyser heating element due to it clogging up. Expensive and a nuisance.

There is also no sediments in my bath once I’ve drained the water out. The iron used to color the white baths and basins in my house. Now it’s no more a problem 👍🏻

Edited by Johandup
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Hi Johandup

To answer you. I will give you the steps I follow.

I suspect you do not oxidize the dissolved iron before the clinobrite filter.

Clinobrite captures particles down to 2 -3 microns  which to me should be good enough.

1. I filter first with a 120 micron mesh to filter clay and other large particles with pressure backwash.

2. Secondly I oxidize the dissolved iron by adding air into the system by means of a venturie. Injecting ozone would work better.

If you do not oxidize the dissolved iron the clinobrite cannot remove dissolved iron. (that is why I suspect your backwash water is clear and the iron gets to the 1micron filter).

3.Then I use a 2 stage clinobrite frp vessels with automatic backwash. I also have a 120 micro disc filter  after this to stop clinobrite particles getting into the system if the sives are damaged in frp vessels.

This alone was not good enough after testing for my household water, only good enough for irrigation.

4. I put in a two more clinobrite frp vessels with automatic backwash and another vunturie. I also put in a frp vessel with calcite to bring up my ph.

5. To complete the filtration  to my jojo tank I have big blue filter with granulated carbon, 5 micron pleated filter and uv light. Carbon also can filter out small amounts of iron.

6. From my jojo tank I have a triple big blue with solid carbon, granulated carbon and 5 micron filter. This is for taste.

You can follow all this from my drawings.

I do not think there is any other media that can do a better job unless you go the injected chlorine route with other media if the ph of the water is high enough which I explain in other posts. 

I also have a gas geyser and have no problem with it using filtered borehole water.

My water has been tested in a lab and all tests conform to all the standards for drinking water.

I will post the place where I buy my iron test kit. There are not many places that sell iron test kits. 


I hope this will help you.

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  • 4 months later...

Upgrading Again

I have found that with my parallel municipal and borehole setup I still use too much municipal water of about 31kl a month.

I will now reduce my municipal water by restricting the input by closing the valve slightly from the municipal supply and checking the flow without the JoJo  booster supply.

I know this will add to more use from the booster pump attached to the JoJo tank.

To minimise the stress on the booster pump I will add a  varem 100l pressure tank to the outgoing line to minimise the booster pump on/off time. At present I only have a 24l booster tank which I do not think is good enough.

I also have already added a smart wi-fi switch to the irrigation section which allows me to control my irrigation remotely from my cell phone and google home(voice activated). This will be handy when on leave.

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Fuenkli I see you are  from Cape Town where their has been  severe water restrictions.

The reason my water use is high is because I have more than one family on my property and we are not as disciplined as far as water usage goes as those from the Cape.

I also irrigate other parts of my property which are not directly connected to the borehole which my sprayers do not reach.

My  total water usesage is split  about 50/50 which means my total usage would be about 60Kl as month.

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I am also going change the position on the 24vac irrigation fill valve to the JoJo tank from just before the JoJo tank to before the 3 frp vessels.

This will relieve the pressure in all the filters  going to the JoJo tank as the line will be open to the JoJo tank when the JoJo tank is not filling.

This will also help in opening  big blue filters to change filters.

Edited by Peter Topp
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  • 5 weeks later...

After adding a 100L pressure tank to my system I still found that my booster pump was switching on far too often. The system had a 24L pressure tank originally.

To check the problem I checked how much water was stored in the pressure tanks after filling  at my meter reading of  4bar (400kpa). Air pressure  was charged at 2.4bar  in both pressure tanks.

I found it stored only about 20L till the water pressure reached 2bar. I should have been about 50L as I have 100L+ 24L pressure tank capacity.

I concluded that there had to be something wrong with the pressure reading.

I replaced the pressure sensor on the pump and found that I had about a 1bar fault on the old pressure sensor. 

After setting up with the new pressure sensor the system now works correctly.

The sensor is a mechanical dial which is tied to coil which expands with pressure.

To conclude it would be a good idea to replace the pressure sensor on a pump every 2 years as it seems as the calibration goes out after time.




Pressure meter.jpg

Edited by Peter Topp
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Some interesting facts on my borehole capacity tests I did this morning on my property.

The test was done with my existing .75kw borehole pump, stopwatch and a Elster Kent water meter.


Borehole Capacity Test


Test done at 20 Canberra Avenue Impala Park Boksburg Gauteng South Africa 1459 on the 05/02/2020 at starting at 07:43 am.

Test done using a .75kw borehole pump, stopwatch and a Elster Kent water meter in a 165 diameter 50m deep borehole.

Borehole depth: with casing 45 meters + plus 5 meters without casing. Total 50m.

Some resistance from 2 X FRP Clinobrite media filters (Zeolite), 2 X 130µm mesh sediment filters and a 20mm venturi during irrigation.


1  1.  Maximum pumping time at 31.8 litres per minutes (time until borehole well is empty while replenishing):  80 minutes.  (03974554L 06:43 ------ 0399363 07:43)

2  2.  Pumping speed during irrigation until borehole well is empty: 31.8 litres per minute or 1908 litres per hour only for 80 minutes.

3  3.     Borehole well capacity without refilling: 1690 litres (1.69 cubic meters).

4  4.  Borehole well filling capacity during irrigation (replenishing): 864 litres in 80 minutes.

5  5. Borehole well filling capacity (replenishing): 10.8 litres per minute or 648 litres per hour.

6  6.  Time to fill borehole well from empty to full: 157 minutes (1hour 37minutes).

7  7.    Steel Casing 2mm thick, inside diameter: 165mm (radius= 82.5mm).

8  8. Height of water from the bottom of the borehole well: 19.75m +1m = (V=πr²) +1 = (1.690/3.14x (0.027225)) +1 =19.75+1= 20.75 meters.

Pump sits 1 meter from the bottom of the borehole.

9  9.  Volume of water per meter for 19.75 meters +1 meter: 85.564L per meter.

1  10.  Water table depth from surface: 50m-20.75m= 29.25 meters.



Borehole Capacity Test 05022020.docx

Edited by Peter Topp
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  • 1 year later...


I have further updated my borehole water system as follows.

After adding a 100l pressure tank which has helped a lot by reducing the motor switching I found that I had to manually switch off the irrigation system when it rains.

To fix this I first bought a rain sensor and integrated it into my system. This seemed to work great however with a rain sensor when the rain stops and the wind is blowing the sensor dries out quickly and the  system will irrigate even if the ground is saturated.

To combat this I use a new device which has just come on the market, which is used together with the rain sensor. The sensor is a  Sonoff Smart Soil Moisture Sensor MS01 coupled to a Sonoff TH10/16.

The device can be set to switch on  and off at adjustable moisture (%RH) values from a smartphone or pc. With all the rain I have had this has helped tremendously and now I can say my borehole water system is fully automatic.

I hope this will help someone with similar problems. 

Edited by Peter Topp
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