Seeing as i am a sandfilter user and i will be stuck with a pressure system for many years still due to the design of my pond i decided to modify my sandfilter with Nevilles new improved koi sand filter hub and fingers.

What am i hoping to achieve with this conversion? I am hoping that this conversion will save me maintenance time on my sand filter and that i will save on the amount of water that i waste during the sand filter cleaning process.

This was my original hubs and fingers in my sand filter. 2 Hubs, one with 8 finger and the other with 3. This was not a bad sand filter at all and i always got very good flow from this system.


Empty sand filter.


Heres the new improved hub and arms that can use air pressure to assist with the cleaning process. After taking the photo i tied to the black pressure air line to the other pipes with cable ties. One modification i would maybe suggest is to maybe replace the white air line with black airline and to also run the black line through the pipes as the white pipe does. The white breather pipe already goes down right into the hub.


I decided to put my valve on my sand filter lid. Its easier and cheaper to replace the lid if i ever decide to sell my sand filter.


This is a top view of the valve ontop of the lid. This is where the air line from the aircompressor connects. I have tested it with my 24l air comprressor and it works perfectly. My Sand filter stand on a pedastal with a drain just below it, so it can overflow with the lid open and not leave a mess everywhere.


I did bubble my sand a bit after conversion and was amazed at the muck that came out of it....and that is after i cleaned it just minutes before in the old traditional way of openeing and stirring as i have done in the years before. I will do some tests on backwashing with a open vs close lid and check if there is a diffrence.

I have not noticed a performance increased in the flow of water out of the sand filter but thats ok, that was not the aim.

I will keep you all upto date on how well this works.

Hi Wayne

Well done man it looks very good, will sommer make you chief installer in the Cape.

Hope it works well for you.

Ok as promissed here are my findings..

I have been running this air system now for about 1.5months and have been cleaning the sand filter twice a week every week in this period. Do i think that the airkit is the final answer for cleaning Sand filters? Sadly No i dont.

The air conversion kit greatly helps one to clean the sand filter. I have found that the best way to clean the sand filter is still to take the lid off and let the sand filter overflow. Cleaning the sand filter (with the lid on) while backwashing with the air on does not clean the gravel properly and spits alot of gravel out via the waste valve.. I find that if one does it this way alot of solids tend to still settle in groups on the edges of the gravel bed. I had to take some solids out by hand as it does not even float anymore. The air is obviously taking the path of least resistance and so one still ends up with areas that dont get cleaned.

I have found that this is the best method to clean the sand filter with air to save water.

1. Take the sand filter lid off.
2. Set the filter to backwash.
3. Switch the pump on and let the filter fill up with water.
4. Stop the pump. The water will flow out till it reaches the level of the overflow pipe.
5. Switch the air on and let it bubble for 2-3 minutes.
6. Switch the pump on again and let the filter overflow.

7. When the water appears clean let the air from compressor out at max velocity for a couple of seconds.
8. Cut the air back so that only fine bubble appear and let the dirt flow out. (I found that if one keeps the air on at full force, the air sucks some of the solids back down again or pushes it up against the wall of the sand filter)

9. Repeat 7 and 8 a couple of times till water is clean.

Today i thought hey let me stir the gravel with a paddel again (first time since i installed the airkit) and see how much dirt is still in the gravel. Shocker!!! I just stirred it a little bit and lots of dark brown particles appeared, enough to let the water that is overflowing the sand filter look like mud.

So although the air kit greatly help i would still recommend to stir the gravel with a paddle atleast once a month.

So now the questions is - is my air compressor not strong enough to do the job? I dont think it is the problem. After cleaning the sand filter many times i found that full force of air from the compressor did not actually help to remove more of the solids instead i found that if one throttles the air from the compressor to let less air through more solids was forced out as it gently floats to the surface. The full force of the air is so strong that it actually pushes the dirt away from the exit as it tries to escape. The strong air force is only useful to turn the gravel inside the sand filter but it is still subject to channelling.

Would i advise people to install this air kit, yes i would. I think although cleaning with air does not take all the dirt out it will help people greatly in keeping it 80% clean and it would definatly extend the time before they run into bacterial problems.

Thanks Wayne, That is more or less also my experience. The kit is what it says, a air assist cleaning kit.

I believe that the bulge of the sand filter is mainly the reason why one should stir it a bit from time to time. The air and water goes straight up and does not follow the curve.

Still believe that it is a great improvement.

I'm glad you mentioned that it is better to backwash with the lid off!

I dont want to drill into my filter, instead I am going to just have the pipe loose on the inside of the filter which is the pipe that will direct the air towards the filter fingers. Then just remove the lid and connect the compressor to the valve...do the backwash etc and then unclip it and leave it on the inside during normal operation.

Hi Cliff,
The problem stays the multiport valve at least with the lid of you drastically increase
the water flow as it now only have to go through that restriction once.

I really don't know why it is a problem to drill through the filter body as it already has holes drilled through it.

Mine has been running some time now without a problem. And the method has been checked and cleared with both the fibreglass as well as the plastic manufacturers of Sand Filters

Just remember it does work with the lid on just slower only better without it. now you have to remove the lid every time.

it's the green filter with the quick release lid. I really dont mind removing it everytime.

With regards to drilling, it's just me. Would rather not incase I drill the thing fooked up which is a possibility and then I'm sitting with a problem.

The problem for me is not whether the sand filter will crack in the long run if i drill a hole in it, i just dont want to drill a hole in it and i think many other people feel the same.

I chose to drill a hole in the lid cause that is alot more acceptable for me than drilling a hole in the side of the sand filter. If this air thingy did not work then all i lost was the lid...and if i ever want to sell the sand filter i can do it without trying to explain to the new purchaser what the ball valve in the side is for....which would propably negativly affect its value as it would be viewed as "broken"

Its very much the same as motor vehicles. The reseller wants all the original parts, he does not care about your custom 17' Mags, turbo intercooler, free flow exhaust and body sportskit that you added on after you bought it. He want to try and the sell the car to the man in the sreet the way it looked when it came on the market. Orginal = safe, Custom = dangerous / abused

Custom anything is usually viewed as problematic and expensive.

Hi Guys

Much ado about nothing, Sand filters are so cheap that nobody is going to buy a secondhand filter anyway. So I think you can put the air connector where you like, as long as it is Inside and not on Top

So is the new generation bead filters then not the way to rather go? Don't you get the same amount of cleaning but a much easier and cleaner back wash with less water wasted? If somebody was setting up a new system and they want to go the pressurised way - would you recommend sand or beads?

Ernst,

I don't think a bead filter can clean as well as a Sand filter, period.

I use the kit and I am very happy with the results, I will definitely not remove mine. It is just if you want to super clean your sand filter then you have to stir it during the air backwash. This is however only necessary periodically.

The bead filter also does not clean itself completely.

It is important that one control the pressure it should not be too high. The volume is no problem.

It seems as if Wayne does not have a pressure regulator on his compressor and is trying to regulate the pressure with the flow control valve.

A little bit of technique and it does work well.

As for what I would recommend, correctly installed, no doubt in my mind. Sand filter it has a cleaning edge over most.

Bead Filter in my experience is very good as secondary filtration in the role of a polishing filter.

The Bead Filter expert Koiland in George tells me that this is very good system for a low wattage pump provided there is a pre-filter system in place...eg. a settlement chamber, or a vortex as a settlement chamber.... to spin out the bigger solids and reduce the workload of the Bead Filter.

There are hobbyist that run a Bead direct, but this seems too much workload with the result that the cleaning process have to be repeated up to 5 times and adds unnecessary work for the Blower.

I do not want to compare a Bead to a SF ... each one has it's own + & - depending on installation method and amount of return lines to pond.

Hi Bobby

I agree with your statement

Just to make things clear, i am very happy with my sand filter & air kit, i was simply giving feedback on the best way to use the air kit and the pros & cons that i have experienced. I have no plans to remove it or to take my sand filter out or replace it.

Something to note is that my sand filter is used more as a polishing unit than anything else. It sits after a settlement vortex and after a pre filter vortex with a eazy & static k1. In my current setup i dont see the advantage exchanging the sand filter for a bead.

If i was to change the pumps from hi wattage & hi pressure to low wattage hi flow pumps then i would install a bubble bead but one thing that is very true....nothing cleans like a sand filter thats why they are such a pain to clean and owners of sand filters have to take the responsibility to try and clean their sand filter regularly to the best of their ability.

very interesting points of view ....

I think the bottom line is that no matter what anyone claims there is no perfect koi pond filter.

Some filters work better than others but the single most important point is that we greatly underestimate the importance of removing solids from the pond water. There are various solids - organic and inorganic. And there are many ways to remove them. (don't forget the multicyclone in your types of apparatus on koi ponds). Speaking of this - I came across a guy who has one on his bore hole for removing the fine silt and solids before the water is used. Works very well.

I also think everyone is in agreement that no matter what you use it is of the upmost importance to regularly maintain the system. Again there is no system that is maintenance free. The maintenance starts with controlling the solids - i.e. algae and fish faeces. Then controlling your stocking densities. The flushing all your filters regularly.

Air bumping sand filters or biofilter beds or vortexes or any koi pond filter using a compressor or Jacuzzi Air blower is a really good way to dislodge the trapped solids.

So we want to reduce running costs - I wonder how much of a part correctly designed piping - large diameter, no 90 degree bends, restrictions in multiport valves over come etc can play a big part in reducing costs. If you can get all the water the pump can deliver to the other side of your system then you can use a smaller pump and save costs. We need to explore this aspect some time.

I was looking at these very low powered but high volume water pumps and wondering about designing a filter around this instead of a simply adding a large pump onto a filter just to try to get good turnover rates. The low powered pumps use something like 250W for 60,000 litres per hour sounds like a good start.

Chris

Chris I could not agree with you more... pond maintainace is not for the lazy, period and all filters work, some better then others but at the end of the day it is how you maintain it.

Hi

Cannot agree more, in the short term and for the existing users I think we have to start at the Multiport valve, this thing is a curse and I clearly see it during backwash with lid open or lid closed, huge differences. Remember you are pumping through that thing twice.
Then of course I cannot understand that we do not have at least long radius bends, 2x Diameter or maybe even 3 times diameter. Currently they are 1.5 x dia.

I am using the vortex system on my second pump and yes they work well, but it is not a cheap system and the flow rate has its limitation, 110 dia. maybe that is why it works well you cannot send water too fast through it. At least to maintain them is also very easy.

Long term well no doubt the design will have to go around the low wattage range of pumps. I find it strange that the manufacturers of filters don't get going on designing a better and more efficient pump.
Come on Chris Marits this one is aimed at you guy,s

This has been my point all along, unless you have the income of Bill Gates the Koi industry will have to look at designing effective systems that can run on low energy pumps and still maintain a good turnover rate. Some of the media available today is more effective with a slower water flow, therefore we need more return lines.

A expert Koi keeper in Cape Town is currently re-designing his filtration and will be running his new systems at half the previous electricity bill whilst keeping the same water flow....... gravity fed and bigger pipework is key to this type of systems. 110mm ....75mm.... 63mm ... suction lines.

We need to explore and understand what air-lifts can do for koi ponds.

Should we fail to be open-minded and explore, the Electricity suppliers will have the last say on our hobby.

As Neville said the multiport valve is a major issue...... I.M.O. those ports are to small for effective water flow.

I recall some years ago that there was a conversion done a the sand filter factory that did not have any multiport valves. It just had 50mm straight in and out and simply had 50mm valves to open and close to re-direct the water.

I will speak to the sand filter manufactures this week. Perhaps they can offer a conversion or make something like this off the factory floor. It would help a lot with flow rates on all types of filters that use the pressurised filter as shell.

Bobby can you contact me directly with the contact details of the koi keeper who is doing a conversion on the pumps and piping on his pond. Would be interested in keeping an eye on this.

Regards,
Chris

Hi Chris,

I have been thinking last night and today and I have some ideas as well as far as the 90 degree bends go as well as the sand filter flow rate.

I will during the course of this week try and modify my sand filter to do just that. 50mm inlet and then from the finger pipe in the inside a 50 mm to the pond as a start, the backwash facility can be changed later. this is not as critical.
I think at the end of the day it may be a bit costly with all the valves needed but in the medium term it will pay for itself. You need about 5 valves for the whole setup.
However I think if we can increase the filtration flow rate for a start it will bring about a big improvement. Unfortunately at this stage not for the escom bill but that will come.

For the bends I have a plan just want to see if it can be made.

I will measure current flow and report improvement if any.


Watch this space.

Just be careful -

Anything that compromises the integrity of the shell or where the multiport valve is attached of a pressurised system COULD be dangerous. Sand filters operate under pressure and you do not want something blowing off and blasting a hole in the neighbour’s wall after passing through a sensitive part of your body.

Chris

Net om hier by julle almal aantesluit die laaste 2maande was ek een van daai lui gate en het net op die Neville kit staatgemaak om my sf skoon te hou dis die verasing wat ek vanoggend kry toe ek die sf uitpak om skoon te maak nadat ek dit gister dis nou vrydag met die air kit skoon gemaak het onthou ek weet dis ontwerp om te help met die skoon maak van die sf

Dit ly heel ok vir my.

Daar is dan 'n man met 'n kamera in die water. Red hom

Well I have also installed my Neville air kit and also ziolite in my sand filter so will see how that all works out I am away again for 4 weeks but will find out from the guy looking after my pond how it is all going.

Happy koi to all.