Turnover rates, pressures and volumes, I think this topic can bring out some very good information for everyone.

Tell us here what is your turnover rate X and why you think it should be that.
As we know the norm is a turnover rate of 50% pond volume per hour, or pond volume every two hours

Pressure is a waste of money in my opinion as koi pond systems only require rather low pressure, but higher volumes.

Ai tog en ek is onder die indruk dis net water toets, water changes en jou visse is happy .Hoe bepal jy jou turnover rate is da n sekere formule wat gebriuk kan word .Deel maar die kennis sodat ek aan die werk kan spring

Hi Frans,
No turnover rate is rather important in many ways, I use to battle to get my water clean and by increasing the turnover rate attained sparkling water, just for one. It also has a lot to do with healthier water for your Koi.
what is wrong to me is to increase turnover rate by increasing pressure.

Neville,

How did you calculate; establishing that your turnover rate in your pond is +/- 50 minutes?

Quote :

I use to battle to get my water clean and by increasing the turnover rate attained sparkling water, just for one.

WoW! Really?

Neville wrote:

Hi Frans,
No turnover rate is rather important in many ways, I use to battle to get my water clean and by increasing the turnover rate attained sparkling water, just for one. It also has a lot to do with healthier water for your Koi.
what is wrong to me is to increase turnover rate by increasing pressure.

I dont really agree with this statement for a number of reason.

1. If you up you turnover rate through your existing filtration by say adding a bigger pump, depending on your filtration surely this will reduce the contact time with your bio filter media and thereby reduce how effective it will actually be.

2. If you increase your turn overrate with additional filtration i.e new pump and filters i can see the benefit. (Rather over filter than under)

If i understand this correctly surely there has too be a limitation to the amount of water your filters and media can effectively process before you need to add more media etc when you up your turnover, yet you also are limited by the contact time. (much the same way as a UV light)

I feel you turnover rate should be proportionate to the amount of filtration you have ?? There must be a balance one can achieve.

You need to determine how much filtration you need and match the flow rate to the filtration quantity and size chosen.

Im still new to all this but this is just my view on it.

Cheers
Lee

Thanks so long for the invormation. On the internet at www.fishdoc.co.uk/filtration/koi5flow.htm i
But it seems to be greek to me chek it out maybe it will make sence
for a simpler explenation

Hi Lee,

Yes you are correct in a lot of what you are saying, the most important being "balance" a pond has to have a balance.

The balance has to include the "2 hour" ratio.
The contact period with media issue has changed a bit since it was found that bacteria grows on the inside of pipe surfaces at full delivery. and the faster turnover will bring the water in contact more times per day. (hope I am making a correct statement here).

Lee, what I was trying to say was that if you don't remove the muck faster than your fish creates, your water won't be clean. Fortunately with sediment you can see this but what about the other stuff, when you see it it is in the form of ulcers or dead fish.

Now this thread is taking the correct direction thanks for your post

Neville wrote:

Hi Lee,

Yes you are correct in a lot of what you are saying, the most important being "balance" a pond has to have a balance.

The balance has to include the "2 hour" ratio.
The contact period with media issue has changed a bit since it was found that bacteria grows on the inside of pipe surfaces at full delivery. and the faster turnover will bring the water in contact more times per day. (hope I am making a correct statement here).

Lee, what I was trying to say was that if you don't remove the muck faster than your fish creates, your water won't be clean. Fortunately with sediment you can see this but what about the other stuff, when you see it it is in the form of ulcers or dead fish.

Now this thread is taking the correct direction thanks for your post

Hi Neville

I understand that you have to remove as much muck at the fish create as fast as they create it to keep the water in good condition for the fish, but im still unsure on the whole two hour ratio you mention.

For example if you have a very lightly stocked pond say two 60cm koi in a 20 000 liter pond surely you can get away without having to turn over the whole pond in 2 hours if you filtration is very effective you don't need such a high turn over rate cause the quality of the water being returned is far better and will maintain the balance of the quality of the water in the pond ??

Take the same size pond and filtration(20 000ltrs) and keep 10 koi 60cm in length, you will need up the turnover rate to maintain the same quality of water then.Will your water now be better than the previous example or the same ??

Obviously both ponds will need to have a mature filters.

Cheers
Lee

Yes Lee

Again what you say is what this thread is about, why do people say certain things. Have they measured it, do they now all the facts, no they don't. Therefore one uses a norm and then you make adjustments to that norm to suit your specific pond, until you have a balance, and you will soon realize when you reach that balance.

Remember this is my views and experiences in my pond, and not that of others. In dealer ponds for example you can only imagine how different their situation will be to our setups.

People tend to read pump graphs and then believe that, that is their pump volume but they have never looked at a pressure gauge, never calculated properly the friction losses. The pumps used by the koi keeper is normally very low pressure pumps and they run out of steam quickly.

Good observations for someone new to the hobby.

LJO42 wrote:

I dont really agree with this statement for a number of reason.

1. If you up you turnover rate through your existing filtration by say adding a bigger pump, depending on your filtration surely this will reduce the contact time with your bio filter media and thereby reduce how effective it will actually be.

2. If you increase your turn overrate with additional filtration i.e new pump and filters i can see the benefit. (Rather over filter than under)

I feel you turnover rate should be proportionate to the amount of filtration you have ?? There must be a balance one can achieve.

You need to determine how much filtration you need and match the flow rate to the filtration quantity and size chosen.

Im still new to all this but this is just my view on it.

Cheers
Lee

I agree Lee
In my opinion the one filter systems, bigger and more powerful pumps is not the answer, contact time with the media is important.
Therefore it starts at the planning stage, deciding on the stocking level you would like to have in your pond and then adding more filters and more return lines to the pond and ultimately the turnover rate to achieve this goal.
I am currently over filtering with 4 systems, 4 low wattage pumps and 4 return lines using less than 1kw in total.
Should I subtract 20% of the manufacturer turnover claims to compensate for height and bends, my pond turnover is once every 55 minutes.

Bobby,

Quote :

Should I subtract 20% of the manufacturer turnover claims to compensate for height and bends, my pond turnover is once every 55 minutes.

How did you calculate that your pond turnover is once every 55 minutes?

By subtracting 20% is definitely not the right way!

Hi Bobby,

Nice to see you involved on this one

Quote :

Should I subtract 20% of the manufacturer turnover claims to compensate for height and bends, my pond turnover is once every 55 minutes.

Bobby this statement is one of the things I am trying to get at, it is a guess and I think one should try and avoid this, as this is measurable, one should physically measure the water that returns to your pond. And only then can you start making other adjustments. We cannot say exactly how much Bio or for that matter sediment filtration is needed. We have to adjust that but with pond circulation in consideration.
Not the ignorant statement I received earlier today that my veggie filter is a restriction and I cannot measure the water return there as it wont be the same as that which flows into my adjacent pond, now how the hell do you explain where the other water goes to.

This Thread is not about how I did things or try to proof me wrong sir or anyone else for that matter, it was posted to see the different turnover rates and why. If you care to listen next time when I try and explain, instead of swearing and shouting at me you might learn something I learned when I was a youngster.

Please remain within the intent of the thread

Keep on trying

Yes I agree that guesswork is involved but with the manufactures specs of 64000lt per hour on a 32000l pond I am pretty sure that my pond return will be under 60min. Luckily I do not use 50mm Toy R' Us BD pipes. To qualify this further the inlet water pipes is 110mm and the outlet pipes is 75mm and 90mm.

If I new how to measure the underwater 75mm pond returns and the x2 90mm gravity fed underwater returns I would do so. I can measure the x 4 overflow 32mm returns but it will serve no purpose. Well I am happy with the results and my fishies are happy with my foolish calculations.

Hello, my daughter is getting married on Saturday and after footing the bill this week, I have to keep the honeymoon going.

Bobby,

Quote :

Hello, my daughter is getting married on Saturday and after footing the bill this week, I have to keep the honeymoon going.

Ek is tog so jammer, maar geluk in elk geval!

Hi Bobby
That sounds fine to me and I agree that you are very close to being correct, a case of monitoring and as you said, adjust.

Pleased to hear about the pipe Dia's at least here you are where I think one should be. As you can only get a certain amount of water through a length of piping of given dia at a given pressure, and do as you like, increasing power will not change that, only maybe increasing the pressure which our swimming pool type pumps are not designed to do. To me the graph of a pump is a guideline,
The actual delivery measured at the outlet (free flow point) is what your pump delivers. the rest is lost due to friction and elevation as well as pump wear and tear.

Pieter J de Villiers wrote:

Bobby,

Quote :

Hello, my daughter is getting married on Saturday and after footing the bill this week, I have to keep the honeymoon going.

Ek is tog so jammer, maar geluk in elk geval!

Dankie Pieter, ek sal haar se as ek haar sien en jou wense oordra, kan maar net hoop dat die "honeymoon" hou langer as my Koi v... filtrasie, sjoe ek kon nuwe "designer filtration" volgens forum spec's insit, sonder dat die bank eers weet.

Bobby,

Ja, en om te dink al die "experts" se raat is gratis!.................of dit nou werk is 'n ander saak.

I can see where Pieter is going with this as one cannot rely on the manufactures spec's on pump volumes. I connected a hose connection to a .25 kw pump to water my garden when doing water changes and was very dissapointed with the volume of water that came out the end of the pipe, much less than the volume and pressure of my tap.

I disagree that a larger pump with a greater turn over rate creates less contact time with bacteria. this depends on the type of filter you are useing.

If you had a bio up - down system and it was 1 x 1 x 1 the contact time will be much less than the same type of filter which is, say 2 x 2 x 5.

Colin Hunt wrote:

I can see where Pieter is going with this as one cannot rely on the manufactures spec's on pump volumes. I connected a hose connection to a .25 kw pump to water my garden when doing water changes and was very dissapointed with the volume of water that came out the end of the pipe, much less than the volume and pressure of my tap.

I disagree that a larger pump with a greater turn over rate creates less contact time with bacteria. this depends on the type of filter you are useing.

If you had a bio up - down system and it was 1 x 1 x 1 the contact time will be much less than the same type of filter which is, say 2 x 2 x 5.

Hello Colin

Change the diameter of the house and do the test again. You can use a 8,000l pump on a 15mm hosepipe and it will take hrs to full 1000lt.

This is the reason we use bigger pipes for the inlet and outlet, the pipe becomes the major restriction for not allowing the pump to deliver. Yes pumps do not deliver as per manufacturer specs, mainly due pipe size, bends and delivery height.

The bigger the inlet pipe the better the back-pressure the better the pump perform to specs.

Media like KI as a example performs at a optimum with slower turnover rates, so I agree different horses for different courses.

Neville wrote:

Hi Lee,

I have done some reading and found this article, Written by someone who knows, I copied and am pasting for you to read.

the second component is the filtration. No filtration system works "up to par" unless the filter is presented with the entire pond's volume every 2 hours. Faster is even a little better, for in all but the largest ponds, "once an hour" is an excellent ideal. Turnover rates through the filter close to once an hour will give clearer water, higher oxygen levels and better quality in general. So assess the water flows of your pond for turnover on par with these concepts

Very interesting

That makes sense but i still feel that you need to factor in the efficiency of your filter, a high turn over rate of ever 2 hours with a filter thats not (up to par mature etc) will be less efficient than a filter thats up to par ( mature, up to par etc), the best way to test this would be to check the quality of the water being returned to the pond.

100 litres of good quality water every hour or 200 litters of half as good quality water every hour ???

The net effect is much the same on the overall quality of your water.

Cheers
Lee

bobby wrote:

Yes I agree that guesswork is involved but with the manufactures specs of 64000lt per hour on a 32000l pond I am pretty sure that my pond return will be under 60min. Luckily I do not use 50mm Toy R' Us BD pipes. To qualify this further the inlet water pipes is 110mm and the outlet pipes is 75mm and 90mm.

If I new how to measure the underwater 75mm pond returns and the x2 90mm gravity fed underwater returns I would do so. I can measure the x 4 overflow 32mm returns but it will serve no purpose. Well I am happy with the results and my fishies are happy with my foolish calculations.

Hello, my daughter is getting married on Saturday and after footing the bill this week, I have to keep the honeymoon going.

I agree its not an exact science and if your fish are happy and your water quality is what you want it to be you have achieved your goal.


oh and Congrats on your daughters wedding Bobby , enjoy the big day tomorrow

Hi,

Interesting thread you started Neville.

There are some sound opinions in the replies and very debatable ones as well. Let me offer another opinion.

You get a pond turnover rate by dividing the pump capacity into the pond volume. So for arguments sake your pond is 20,000 litres and you pump has a capacity of 10,000 liters per hour your pond volume turnover rate is 2 hours. That is under ideal conditions but there are a host of factors that affect flow rates.

The question is why do you want a fast turnover rate on a koi pond? The answer is you need to remove the toxic ammonia as quickly as possible from the water and you need to replace the vital oxygen the koi use as quickly as possible.

There is another consideration - ambient ammonia. As a portion of the pond volume is being cleaned and filtered in the filters the koi are still excreting ammonia. So there is never actually zero ammonia in a koi pond! As stocking densities and feeding rates increase so does this ambient ammonia level. By increasing the turnover rate the ambient ammonia will become less and less until you cannot register it on a hobbyists test kit.

As stocking densities increase so does the oxygen consumption. The pond water can only hold a certain amount of oxygen. In order to replenish the oxygen - and to de-gas the carbon-di-oxide - you need to increase the turnover rate.

Another factor related to turnover rates is solids and organic build up. Algae can reproduce its self very quickly in summer. Dust and other pollutants blow into the pond continuously. Bacterial bio films are continually sloughing. Added to this the solid fish faeces - which can be quite substantial.

So as the organics and solids are build up in the pond a small amount is being removed in the filter system. When the organics build up quicker than they remove the water becomes cloudy and not really clear.

To clear the water you need to reduce the organic build up and/or increase the turnover rates.

That’s the basics. I have written several detailed articles on this very subject for KOISA which should be published in the next month or two. Members of the koi society will get the benefit of this information. (That's an unashamed plug for the Koi Society).

Then we move onto how to achieve good flow rates and matching pumps up to filter chamber surface areas, frictional losses, contact time in biofilters etc. etc.

So basically the faster the turnover rate the better for the whole pond and your koi collection.

This is a fascinating part of koi keeping.

Always keep in mind what Prof Dominique Bureau of the University of Guelph says about koi keeping -

"Koi Keeping is a peculiar mix of hobby, art, science, and commerce."

Kind regards,
Chris

[i]

Hobyyist underestimate the value of the suction and delivery pipe size and expect s high volume pump to do the job. A practical lesson i was taught by Drikus and Christie from Cape Koi Aquarium.

The general rule that a 110mm pipe will deliver 14000l of water.

Now using a 50mm pipe as a suction pipe with a high flow pump, what is the flow per lt expectations from a 50mm suction pipe?

The question where is the restriction that is responsible for the big drop in water volume? The suction or delivery line?

In my view and practical experience the bigger and shorter distance the suction pipe is from pump the less water volume loss on the delivery side.