I'm new to aquaponics...been reading a lot over the last week. I drafted up a guideline to work off of in fine tuning the design, and was wondering if you all could take a quick look at the sketch and suggest anything you see that might be out of line or a bad idea?
Appreciated much your input...
Did you mean 300GPH? You won't need air going to the growbeds - flood and drain takes care of that. You should also design in an overflow to your growbeds and research CHOP 2 or CHIFT PIST systems that integrate a sump into the system so that your fish tank doesn't doesn't rise and fall as the siphons cycle.
Assuming you meant 300 gph on the pump.
I will recommend you go bigger on the pump since you should probably plan to actually move about 300 gallons per hour at least and a pump that is called a 300 gallon per hour pump will not actually move that much water once you actually lift it up to the grow beds.
1" pipe is probably big enough from the pump up tot he grow beds but knowing me, I would probably make the vertical pipe up out of the pump 1 1/2" and then when I branch out to the grow beds I would drop down to the 1" pipe.
And you don't need air stones in media beds, Send all the air into the fish tank (and if you add a sump tank you can throw a stone in there but no point in trying to put air into gravel beds.)
Adding overflows to the grow beds is a good idea.
As to your Drain line. Your stand pipes might be ok at 1" each, however Gravity drains always need to be bigger than the pumped flow into the beds. So if you were to drain each bed individually back to the fish tank or sump tank, then maybe 1 1/2" or 2" drains would be ok but if you combine all three, I would say go 3" on the combined part of the drain line.
Be sure to plumb in a bypass on the line out of the pump. A bypass is a T and a ball valve to allow excess flow back into the fish tank so you can adjust your flow rates without choking back your pump which would be hard on the pump. The excess flow going back into the fish tank simply provides more aeration and you can angle the flow to create a current and help move solids around and back to the pump to go to the grow beds.
TCLynx and Jonathan
Thanks very much for the great tips...I'm going to implement all the ideas you both gave me. I will design a sump in also as you both suggest. (Thanks for catching the 300gph... at 300 gpm it would have been very exciting upon fire-up of the system). :-)
I thank you both again for your time and for giving my sketch serious consideration...I'm going to take my time on the design side-before I jump in. Also lots to learn about balancing the water with the fish I'm deducing from what I'm reading.
OOPS, forgot 1 more question... do you know approx how much actual water a 16 CF grow bed holds ? The media will obviously take up some of the volume, so I was wondering if anyone has a ballpark number of gallons ?? My guess (which I have nothing to base this on at all) would probably be about 50 gallons maybe ???
50 gallons after displacement (38%) sounds about right. (Probably a little less since you wont be filling it to the brim and your waterline needs to be an inch or two below top of your media).
If I may just add...Balance the fish stocking density according to your bio-filtration capacity...and not your water volume or fish tank size.
Ok Vlad... I'll research what that means exactly...and I'll follow your advice.
Thanks very much for the help.
I think you might find a good starting point on the "Rules of Thumbs" page with some of the basic ratios to start from. It's not infrequent that people get caught up on the fish pounds per gallon of tank figures, but forget that that means didley-squat if you don't have the bio-filtration capacity for that amount of fish...It will save you head aches later. Use your 3 media beds to determine your maximum fish load and minimum tank size.
Will do...I'll look up the references asap. I've been working on redesinging a sump into the system...be done with draft#2 soon.
Thanks again Vlad for the assist.
oh, by the way.
When you figure how much sump tank volume you need to handle flooding all your grow beds, the easy way is to simply figure about half the volume of your grow beds plus a little to make sure the pump doesn't have to suck the last drops out of the sump tank to do the job.
The normal rule of thumb is that the grow bed requires about 40% of it's volume to flood it (yea this is very rough and variable.)
So I normally figure I need 50% of my grow bed volume to be able to flood them (this gives me some leeway so I don't have to make sure the tank it topped right to the brim every hour ya know.) I also like to add a float type top up valve so that the system will automatically get topped up when the water level falls below the normal low water mark but still above the pump sucking air level. I'm lazy and would rather the system look after itself instead of expecting me to top it up all the time. Also, if you have city water, topping up small amounts often is far better than sudden big top ups of treated water. A well cycled system can usually handle 2-5% treated water top ups but as soon as you are adding a lot more water than that, you should be neutralizing the chlorine or chloramine before you put it in the system.
TC those are stellar links. Thanks for making that information available. I especially like the dual bypasses in both the sump and fish tank in the very last indexed CHOP2 system in the plumbing presentation. I am assuming the sump bypass is only open when the fishtank bypass is closed while working on the tank?
Chris, it is all just to allow for balancing the flows and in a system like that, you are right in that you are unlikely to operate with much if any water going back into the sump by that sump bypass unless you had a really outrageously oversized pump for the operation. The indexing valves take a fair bit of flow and pressure and you are likely to have to keep the bypass to the sump closed unless you were to close the fish tank bypass for something like say lowering the water level to help in harvesting fish.