Hi all,
This is my first time on this forum and I have been enjoying a number of the threads. I have a question. I am still relatively new at this - I put in a 2000 gallon pond about 1 1/2 years ago. I have koi and a number of plants. I also have a time of use electric rate where the cost of electricity between noon and 7PM on weekdays during the summer months is exorbitant. The idea is to 'encourage' off-peak use. So I would like to know if it would be okay to use a timer to shut off the pump for most or all of those seven hours. I have read that the pump should not be turned off at night because the aeration is needed, but what about during the day? Would it harm the koi? Thanks.
Victor
Can I shut off my pump during the day?
Victor,
I assume that you've got a biofilter for your pond to help take care of fish wastes and convert ammonia over to nitrate (nitrification). If you turn off your pump the biofilter will go anaerobic within an hour or so killing off the nitrifying bacteria on the media. Not sure what size pump you're using, whether it's submerged or not, or whether you're driving several extensive water features. However, there are numerous pumps out there that don't draw too much power. I've got a pond somewhat larger than yours and the main pump is a Laguna 7000 which draws approximately 130 watts (your pump should have a tag or be stamped with the information on how much power it draws). But there are pumps out there that will use up a great deal of power and so I understand your concern!
Excellent answer. I second it: don't turn off the pump!
Thank you. I have the large Aquascape system with Biofalls. It has a bio filter. It's a large pump - draws about 600 watts - that's why I want to cycle it. Does the good bacteria really die that fast? I read that the Autumn / Winter bacteria I added last Fall survives the winter and will begin to get active when it warms up - all the time with the pump off. With the waterfall running for so many hours a day, isn't there quite a bit of oxygen in the water? Thanks again for your help.
Victor
Hi Victor,
Several points. 1.) During the summer the water temperature is much higher and as a result it will hold much less oxygen. For example, when the water temperature is around 70°F then it can only hold about 9 mg/L of oxygen. During the winter or fall if your water temperature is around 40°F then it will hold approximately 13 mg/L. On top of that, during cold temperatures the bacteria are not nearly as active and so consume much less oxygen. Which of course means that during the summer they will consume oxygen at a much faster rate. 2.) The major bacteria of concern on your biofalls filters are the nitrifying bacteria. If you look at the metabolism rate for the bacteria that fall in this category you'll see that they consume significant amounts of oxygen and are sensitive to low levels of oxygen. If your system goes anaerobic or even near anaerobic it will cause the microbial layer on the filters to sluff off or drop off; it will also cause most of the nitrifiers to die off. It won't kill 100% of them - that's correct, but it will significantly reduce the capacity of your filter to properly handle the amount of ammonia produced by the fish. The result of the constant cycling on and off will be a biofilter starved for oxygen during the down time, poor nitrification and accumulation of ammonia in your pond. 3.) You did not indicate the fish load or the rate at which you are feeding your fish. This also will influence the amount of ammonia produced in your system. 4.) In my opinion the rating for the pond capacity for the biofalls unit (and it's not just them but many other similar units as well) is over stated. I also have a biofalls unit and have added a Skippy filter and a Trickle Tower just to add extra biofilter capacity (approximately 2000 sq. ft. of surface area). I am carrying a fish load of 3 - 20"+ Koi, several Shubunkins and about 3-4 dozen (they breed faster than I can count!) Comets. During the summer I feed approximately 2 cups of pelleted food spread out over two to four times per day - basically what they'll consume in about 2-3 minutes at a time. All of which is why I am carrying a much higher filter capacity than most. Hope all of this helps.
My answer will be less technical. Yes, the good bacteria does start to die off quickly. It basically suffocates if the oxygenated water is not kept moving over/through it. The filter will "sour" while it is not running and then when it is restarted it will dump accumulated wastes and toxins back into the pond. Not good.
There is quite a bit of oxygen in the water, but remember that the fish use it too. Without circulation, the water settles into layers. This is good in the winter when you want to conserve heat at the bottom of the pond, but bad in summer when the oxygen must be replenished constantly at the surface of the water due to the higher demands of aquatic life in the warm water.
Cold water will keep lots of things dormant, including fish and bacteria. They both survive because they are not using a lot of oxygen (that isn't there anyway). Active and awake life uses a lot more oxygen and needs that water movement and surface exchange to survive.
Sure, most of the time ponds and pond life survive things like power outages, heat waves, and malfunctioning equipment, but these situations cause stress to the fish and the pond environment. You want to avoid stressing your fish if at all possible, because it makes them weak and prone to disease.
Hope this helps. Maybe you could set up a smaller pump to run during the day that would maintain circulation and oxygenation but use fewer watts of electricity.
Oops. Posted at the same time and did not see the previous answer.
This message was edited Apr 13, 2005 10:14 AM
Thanks to both of you. I'm convinced - keep it going all the time! I appreciate the in-depth answers. DRH2, I have 13 5-7 inch koi. How involved is it to add the additional filtering? I try not to feed them too much (twice a day - what they eat in a few minutes) and I continue to add plants as well. Any other advice? Thanks again.
Regards,
Victor
Adding the additional filtering is very easy. All I did was put a smaller pump in the skimmer box - Laguna 3000 (along with the Laguna 7000) and I pump water to the filters and then return it to the skimmer box but ahead of the filter pad. This means that some of the water will be re-circulated through the outside filter units but I can also close them down when I don't need them (flexibility). As to building it/them? Here are a couple of websites that will help with DIY-type projects:
http://www.skippysstuff.com/biofiltr.htm
http://livingjewels.com/DIY/trickletower/tt.htm
Obviously the first one will give the gory details on building a "Skippy Filter" which is a submerged-media filter and the second one will provide the information for a Trickle Tower (see the link in the lefthand sidebar). I built both mostly out of curiosity as well as being fairly certain that the biofalls unit was undersized. Of the two the "Skippy Filter" is probably a bit more expensive mainly because of the cost of the Rubbermaid stock tank. I used a 50 gallon, plastic barrel that had been used for holding commercial amounts of pickled peppers!! Obviously had to clean it thoroughly. The barrel was on sale for $20 at our local Agway (farm and feed store). But you can also get used apple juice barrels, etc. Anything works for the biomedia - knives, forks from the church bazaar, plastic scrubbies for example. Good luck, have fun!
Thanks so much. Your help has been invaluable.
Victor
The pump is sized for the pond. A smaller pump would not give the sufficient flowrate. The waterfall would be a trickle and there would be less oxygen - I would probably end up spending more on treating more water problems than I would save on electricity. Thanks.
Victor
Hi Victor,
What you say may be true. But I'm putting in a 4000 gallon pond and my pump pulls a maximum of 404 watts. (minimum of 112). It has a max flow rate at 5' of 3220 gal/hour, so it will easily recirculate my water more than once every two hours. I did a lot of shopping around and one of the things I looked at was how energy efficient the pump was. This was not the MOST efficient pump, but it was in the mid range and the price was right. I have a Calpump PW3500.
Also, I considered using an external pump as they are much more energy efficient than submersibles as a general rule. I was concerned about noise level and, again, this pump was very inexpensive to buy up front, so I went with this one. If I'm dissatisfied with it after a year, I'm going to revisit the external pump issue.
At any rate, hope this clarifies what I meant by my post. I certainly agree that you don't want to reduce your flow rate!