Figure since we're on the subject of pump's and flow rate... thought I'd give a quick post about turn over rate and using it to help you determine which pump size to purchase.
If anyone's curious about turnover rate, whether it should be 1 per hour or 3 per hour or 6 per hour, then this all depends on your filtration system and the electricity and pump you're willing to afford.
"Turnover rate" is how long it takes for the entire pond's volume to flow through the filtration system to be "refreshed". Fish are constantly producing ammonia and the sooner this is recycled then the better. Example: 1000 gallon pond with a 6000 GPH pump has a turn over of 6 times per hour.
Also, turnover rate is mutually exclusive with dilution rate, that is assuming an
efficient filtration system is installed able to handle the higher flow rate. Example: 6 times per hour has a 6x dilution rate, which means a 1000 gallon pond becomes a 6000 gallon pond to the fish. However, do not forget the pond's physical dimensions, which would still restrict number of fish within the pond.
Higher dilution rate essentially means the water is more "fresh" for the fish. I am reading more and more from avid koi hobbyists doing a 3~6x turn over and their fish are growing better along with having better appetites and stronger immune systems. Big win-win here.
This is further validated by University of Maryland in the document,
RAS: An overview of Waste Management, which states, "Aquaculture wastes are released directly into the water. Hence, aquaculture wastes are often given in mg/L. Most of the data for fish tolerance to various pollutants (e.g. ammonia) are also available in mg/L. However, dilution has always been one solution to pollution. In two recirculating systems that have the same fish load and are fed the same ration, the pollution load in one system may be ½ that in another simply because the water flow rate in the second is twice that in the first system. Thus, one must look carefully at pollution measurements and determine exactly what they mean."
Also folks, don't use the coefficients in that document since it assumes a generalize feed protein ratio... Rather... Use the below formula if wanting to calculate the amount of ammonia generated by fish feed, that is the ammonia generated due to feeding fish. Also, keep in mind that, after taking into account microorganism energy in the nitrification reduction, ammonia and nitrate has a 1:1 ratio. There may be a slight, quite near irrelevant, variance between fish species.
TAN = [ (gramsFeed*proteinFeed*0.092) / 18.03851 ] *62.00502
This was shared to me by Mr. Van der Werf, whom is the fella that operates
Earthan Group for hobbyists and is an active industry professional in integrated recirculating aquaculture systems, that is aquaculture (fish farming) plus hydroponics (plant farming), and I make mention of him in the thread:
Is aquaponics farming commercially viable?. This formula is also talked about by Dr. Timmons (of Cornell University) in his book
Recirculating Aquaculture Systems, 2nd edition; not for sure if it is mentioned in the new 3rd edition of his book or not.
