Aquaponic Gardening

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As stated in my last post i am now looking for a pump to run a dwc system. what is the general rule on pump capacity? i think i read somewhere that said that the entire system water must circulate once per hour, is that correct???????????

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The water in the fishtank must circulate once per hour.


is it that the water in the fish tank must circulate i.e. if i have a dwc system with a 400 gallon tank and two 4 x 20 x 1 troughs  should i aim at making sure that the water is moving at 400 GPH(fish tank capacity) 

should i make sure that the entire water in the system is circulated once per hour?????

Irie mon!!!!!!!! 
Jovan Johnson  

Mörður Gunnarsson Ottesen said:

The water in the fishtank must circulate once per hour.

My current system has a 330 self constructed tank & a 250 polly (not yet plumbed into the system).  These tanks have a gravity feed draw off  at  about the 1/3rd from the top level.  Water gravitates into 4  4ft x 8 ft grow troughts 1ft deep. This inturn gravitates into a 30 gallon sump where a 2800 GPH sump pump returns the water to the fish tanks.   Because my 250 gal. polly tank is not plumbed into the system.  I have purchased a number (4) of 70 GPH fountain pumps (about $20 ea.) from Lowes .  These pumps are submerceable.  The pump is lowerd half way into the tank and discharges back, via 1/2 inch tubing to the grow troughts. I have added a plastic  "Y" fitting to the discharge hose from my sump so return warter goes both to my 330 gallon tank and my 250 gallon polly tank. I would guess gravity flow via 1.5 inch PVC pipe at also about 70 GPH.  So this would mean I am circulating 140 gallons of water per hour.  In summary system has total of 580 gallons of fish tanks. 140 gallon @ hour circulating.  Sump pump runing 24/7 = 3,360 per day or 5.78 times complete water exchange.

I think the system would still function well if the pumps just ran 8 hours a day.  I say this because I have done that for several months when I first got my fish. 

Jovan, in raft systems we typically want a minimum of 5 gallons per minute of flow in 4' wide and 12" deep troughs. The Friendly micro system uses about 2 GPM. I prefer 5-10GPM. More the 10GPM can be used but is not necessary and makes your power bill higher. The rule of the entire system turnover each hour is for media systems not rafts.

I am now using a two pump system to save power. I use one small pump to take water from my sump to the fish tank which is about 4 GPM.  I use a second smaller pump as a looping pump between trough 1 and 4. I have no measurable nutrient drop between the beginning of trough 1 and the end of 4 so I do not find it necessary to raise ALL the system water to the highest point. My looping pump is less the 1/2 the rating as my main pump but puts out more GPM since it is pumping flat instead of raising water(pump curves drop with elevation).

oh i see. so i dont need to buy a 1200 GPH tank since it is very expensive(12000 JMD) and not necessary(since  i am not aiming for complete water circulation in an hour). i think i will opt for a more affordable 500GPH submersible pump which should be suitable from what chris is saying, it should produce a 8.33 GPM


Yes you are correct if you are pumping without much head(the height you are pumping between the highest point and the lowest). Most pump ratings are based on one foot or less of head. The higher water is pumped you get less the output. All reputable pumps will give you a pump curve or some kind or state outputs for certain heads. Use the pump  curves to determine if the flow rate is in an acceptable range with the head that you will be dealing with.


i Love this site, knowledge is just flying about the place.

The selection of pump is still one of my smaller problems. 

I have to get the system constructed first. 
Still a bit nervous, tell u what when i get back to school( about Wednesday) ill take some picks of my proposed site and if ypur free we can have some more discussion on system component.




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