Home | About Us | Contact Us


Koi Forum - Koi-Bito Magazine straight from Japan
Results 1 to 10 of 10

Thread: Optimal Pond Turnover Rate

  1. #1
    Oyagoi Lam Nguyen's Avatar
    Join Date
    Aug 2007
    Location
    Portland, Oregon
    Posts
    1,671

    Optimal Pond Turnover Rate

    In your guys' opinion, what is the optimal pond turnover rate? I have heard anywhere from 15 minutes to 2 hours and was just curious as to what you guys think. Obviously there are many determining factors so I will try and specify a few of them:

    Pond size: 12,000 - 20,000 US gallons
    Pond shape: Rectangular (approx 10' W x 22.5' L x 10' D)
    Filtration: Two Nexus 300, two full BHM trays, one Ultima II 10,000 or 20,000, and/or one 4' W x 22.5' L x 6' D filter bay full of Japanese mats.
    Filtration Volume: 25-30% of pond total volume
    Goals: To grow koi to jumbo size and keep ambient ammonia, nitrite, and nitrate at traceable levels.

    What are your guys' thoughts?

  2. #2
    Honmei
    Join Date
    Jul 2005
    Posts
    2,744
    First of all, there is a huge difference between 12,000 and 20,000 gallons. On a 12 thousand gallon pond, 2 bottom drains would be adequate for a 10' deep pond...marginal for a 6' deep pond (floor surface area coming into play). On a 20,000 gallon pond you need 4 bottom drains and corresponding filtration circuits.

    Now, to answer your question, optimal turnover rate (throuigh bio filtration) would be less than 1 hour...better at around 45 minutes. Do not count bead filters into this equation either since they are primarily for mechanical filtration.

    Steve
    The views presented are my personal views and not that of any organization that I may belong to unless otherwise specified. [email protected]
    CKHPA

  3. #3
    Jumbo jnorth's Avatar
    Join Date
    Mar 2005
    Location
    VA
    Posts
    3,159
    Just curious Steve.....but don't the English generally have a longer turnover rate?
    Koi-Unit
    My personal koi page Updated 7/8/07
    ZNA Potomac Koi Club

  4. #4
    Honmei
    Join Date
    Jul 2005
    Posts
    2,744
    Quote Originally Posted by jnorth View Post
    Just curious Steve.....but don't the English generally have a longer turnover rate?
    Yes they do...2 to 3 hours typically. I suppose you want to know why there is a difference?
    The views presented are my personal views and not that of any organization that I may belong to unless otherwise specified. [email protected]
    CKHPA

  5. #5
    Oyagoi Lam Nguyen's Avatar
    Join Date
    Aug 2007
    Location
    Portland, Oregon
    Posts
    1,671
    I am interested in knowing why there is a difference. Now that you mention it, the literature with longer turnover rates (1.5 - 2.5hrs) were from one of the English countries.

    Steve, do you know if there is a difference between 45min and 30min complete pond turnover, or is this difference too insignificant to see a difference in water quality?

  6. #6
    Honmei
    Join Date
    Jul 2005
    Posts
    2,744
    Quote Originally Posted by Lam Nguyen View Post
    I am interested in knowing why there is a difference. Now that you mention it, the literature with longer turnover rates (1.5 - 2.5hrs) were from one of the English countries.

    Steve, do you know if there is a difference between 45min and 30min complete pond turnover, or is this difference too insignificant to see a difference in water quality?
    Hi Lam, I will answer your second question first. There is the law of diminishing returns where at some point, increasing turnover rate yields less and less noticeable results. Where that point is is very hard to determine because those results (the koi's growth, health and developement) is also affected by other factors.

    Now as to wehy there is a difference between older, English turnover rates and new US turnover rates. Ten to fifteen+ years ago, turnover rates were based upon clarity as much as anything else in the UK With England being so much further north and with such a shorter growing season, a 2-3 hur turnover rate coupled with reasonable stocking densities yielded healthy koi and clear water....but, the slow growth was attributed to a shorter growing season when in fact it was also affected by higher ambient nutrient levels within the pond. In the US, a 2 to three hour turnover rate with a much further south location, higher temperatures etc yielded green water and the further need for UV lights to maintain clarity but yet still having high ambient nutrient levels. By increasing the turnover rate (through a media with excess surface area and that could remain free of detris), ambient nutrient levels lessened, green water disappeared even without UVs in most geographical areas and growth rates increased along with the longer growing season. Couple that with more water changes for further dilution of unfilterable items (pheromones and nitrate) and you begin to have a pond set-up to grow koi in excess of 30+ inches in a 5-6 year period verses 10+ (if ever).

    Steve
    The views presented are my personal views and not that of any organization that I may belong to unless otherwise specified. [email protected]
    CKHPA

  7. #7
    Oyagoi RayJordan's Avatar
    Join Date
    Dec 2003
    Location
    San Antonio, Texas
    Posts
    1,780
    Kind of like the question how many koi can I put in a 10,000 gallon pond. It is impossible to give a single best turnover rate time without a lot more information. Several issues figure into best turnover rate time.

    Mechanical removal of solids are an important variable and depending on the type of mechanical seperation system you are using i.e. Settlement chamber, strainer, etc. too much flow will prevent fines from setting. Too slow will cause fines to settle on pond bottom, plumbing runs, etc. Also over all pond design including bottom slope and bottom drain design and plumbing capacity are all points to consider.

    Biological filtration is a seperate issue and while the nitrification chemical reaction is almost instantanous water moving through the biofilter has to be able to deliver the ammonia and nitrite molecules to the bacteria growing within the biofilm on the biomedia for nitrification to be accomplished.

    So filter dwell time is a issue for both mechanical solids removal and bio-conversion.

    I have seen ponds where increasing the turnover rate reduced the clarity of the water and also the reverse. I have seen ponds where increasing the turnover rates dropped the ammonia and nitrite levels to were they were undectable and also where they caused them to increase.

    Regardless of how well you design you pond/filter system there is still some uniquness with each one. Being able to adjust the flow rates via up and downsizing pumps and/or flow adjustments allows you flexability as your pond matures, fish load grows, and seasonally changes occur.

    All that said I tend to reccomend something between 1 hr to 1.5 hr for the average outside 10,000 gallon pond/filter system. Indoor systems with less solids to deal or smaller systems can usualy function with a more rapid T/O rate. Larger ponds can usually get by with the 1.5 to 2.0 hour T/O rate.

    Remember the increased costs of faster flowrates(larger pumps and more watts per hr) is also becoming a more important issue for many.

  8. #8
    Oyagoi Lam Nguyen's Avatar
    Join Date
    Aug 2007
    Location
    Portland, Oregon
    Posts
    1,671
    Thank you Steve and Ray. Points very well taken. Steve, I am ALL FOR growing koi to 30+ inches in 5-6 years any day! Please tell me how!

    Over the months, I have learned that the saying "if you can't run with the big dawgs, then stay on the porch" is very applicable to this hobby. And in order to run with the big dawgs, you must have excellent caliber koi. But, while anyone who puts their mind to it can go out and buy these GC-caliber koi, do they have the husbandry skills and FACILITY to allow these koi to blossom? This is why, in order for me to run with the big guns in this hobby, I must first have a state of the art facility, and hence my devotion of late to learning and researching about the characteristics that make a system THE IDEAL system......but then again, is there such thing as an ideal system? It is this journey that really makes me tick about this hobby.

  9. #9
    MCA
    MCA is offline
    Honmei MCA's Avatar
    Join Date
    Dec 2003
    Location
    Atlanta
    Posts
    2,574
    what is the optimal pond turnover rate
    fast enough to keep ammonia and nitrite to virtually zero, DO and ORP high....and slow enough so that you are not paying needless high energy bills. The proof is in the water quality growth rates.

  10. #10
    Honmei
    Join Date
    Jul 2005
    Posts
    2,744
    I'll agree while taking a tad bit of exception to Ray's post. First of all, there are trade-offs in this hobby as there are in life. There are also differences between "optimal" and "acceptable" and both are "ranges" verses hard numbers. While we talk about "turnover rates," we are talking specifically about how often the pond should turn over through bio filtration and not any of the other components that can also come into play such as what Ray points out concerning mechanical filtration concerns. Remember, someone once (and at every chance) says that, "It's a System" and all factors should be considered in an overall design. All that being said and while 1 to 1.5 hour turn over rate is fully acceptable (and typically what I design for) and will yield very good results, a 45 minute to 1 hour rate (through a properly designed, overall system) will yield better results.

    Yes, mechanical filtration concerns change and can change dramatically. Yes, power consumption also changes and must be considered as well when taking this path. Many other considerations can also come into play such as flow through designs for further nutrient/pheremone dilution but there are tradeoffs to consider here as well such as the components of the source water itself.

    HenryC, Bob W and I gave a talk this last weekend at the AKCA seminar on Growing Jumbo Koi. The three basic components are, "Genetics, Environment, and Husbandry." Of course each of these can be broken down into many detailed components but when you check around with those that have actually grown 30" + gosankes, it becomes amazing how many similarities there are between each...with perhaps a few twists here and there.

    Steve
    The views presented are my personal views and not that of any organization that I may belong to unless otherwise specified. [email protected]
    CKHPA

Similar Threads

  1. Optimal Feeding Frequency
    By MikeM in forum Main Forum
    Replies: 13
    Last Post: 10-22-2013, 01:06 PM
  2. Replies: 36
    Last Post: 09-30-2005, 04:26 AM
  3. what pond turnover rate do you think is best?
    By tewa in forum Main Forum
    Replies: 5
    Last Post: 09-03-2005, 11:12 AM
  4. Replies: 1
    Last Post: 08-30-2005, 11:33 PM
  5. TURNOVER RATE vs SETTLEMENT & CONTACT TIME
    By Akinosan in forum Main Forum
    Replies: 3
    Last Post: 07-05-2005, 07:34 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Articles - Sitemap - FAQs and Rules

KB Footer Graphic
Straight from Japan... For the serious hobbyist!
All content and images copyright of: Koi-bito.com