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Comment by Elizabeth on March 2, 2012 at 12:00pm

You're right!!!

Comment by Chi Ma on March 2, 2012 at 11:59am

Don't over think it. Just jump in head first :)

Comment by Elizabeth on March 2, 2012 at 11:57am

Thanks Chi,  I should come over some time and check out your system before I build anything.

David,

Here is another possibility from Home Depot.  Much cheaper.

APC 350-Volt 6-Outlet UPS Battery Backup

Model # BE350G

Internet # 202075461

$40.51 /EA-Each

The key thing here is that if you have an AC pump you need to be able to provide AC power from the backup power supply.  IF you have a DC pump, you need DC power.  A DC pump might be nice if you want to run everything off of a battery and use solar panels to charge it.  There is at least one YouTube video on doing this.

Comment by Chi Ma on March 2, 2012 at 11:45am

Elizabeth, you are pretty close to me. If you need an emergency pump relay built let me know. I have plenty of leftover parts.

Here is an inexpensive bilge pump.

http://www.amazon.com/Shoreline-Marine-Bilge-Pump-600/dp/B004LRBI9A...

Comment by Elizabeth on March 2, 2012 at 11:42am

David,

The sequencing valve was intended to let me fill each of my "1, 2, .., n" media beds with the same amount of water independent of their relative height above ground or that of their pipe inlets.  If you try to fill them all with a single pipe that has multiple outlets, some will fill more (the ones with the first outlet) and others less.  This is because as water exits at the first opening, the pressure changes so there is less to drive the remaining water through the pipe to the other beds.  

A sequencing valve lets you set the amount of time that each line is open to feed the beds, but only feeds one at a time.  This way the water fill is controlled by the time the valve is opened and the pump pressure.  This is a good idea, but it adds another component to the system, which costs money and can fail.  I have never used one so I don't know what problems people have had with them.  Another way to do this is to add a ball (or other flow control) valve to the input pipe to each grow bed.  By adjusting the valve you can control the flow rate into each container, thus you can control the amount of water during any pump cycle.  This costs money too, but the valves are passive components and can be set up once and left alone (unless they clog).  This is of course infinitely expandable and also lets you compensate for different size media beds that require different amounts of water (within reason).  The down side to this approach is that turning a ball valve may not be real precise and it may be hard to adjust them to really work well this way.  But I have seen a few setups that purport to work well using this method.  The key to this approach is that you want to use one pump and one pump cycle and control all of your media beds simultaneously.  I will probably try the valves first as they are effectively fail safe.

I think that the shower head is a good idea, and it is cheap.  A few folks told me that it would clog though.  I'm still thinking about it.  The only problem I can see is potential clogging. 

Comment by David Schwinghamer on March 2, 2012 at 11:24am

I was looking at your drawing and noticed you are gonna use a showerhead to return the water to the fish tank. I am doing something close to that and wouldnt worry too much about clogging because the media cleans so well. Maybe over time it may collect. What exactly would the sequencing valve do?

Comment by Elizabeth on March 2, 2012 at 11:21am

Yeah, that's a lot.  I'm sure that someone has come up with a cheaper way to do this.  The emergency lighting has a nice metal fixture and other stuff that you pay for but don't need for this application. 

Comment by David Schwinghamer on March 2, 2012 at 11:18am

That is a very good idea, thanks. Dont know if its worth 173 for me to do that though.

Comment by Elizabeth on March 1, 2012 at 11:22pm

Hi David,

I am still debating about containers.  I bought a bunch of (~20) dark black HDPE containers from a retiring dock maker last year who was moving from the Bay area back to Nova Scotia.  They are 10 ft long x 30" high x 24" deep and very sturdy thick plastic.  They are meant to go under wood planks and act as buoyant floats for docks.  They were cheap too, only $20.00 each.   I think that this would be good for both the fish tanks and the media beds.  I am also looking a cement mixing tubs for the media and raft beds, and the sump tank.  These are available at Lowes in two sizes and are also pretty inexpensive.  But I'm still thinking about the IBC systems.  What I don't like about the IBC tanks is their susceptibility to UV degradation. But the frames are nice and they are sturdy and a good size to work with.  They are also readily available and can be easily replaced.  You can also hook stuff to the frames, which I find to be really useful.

In terms of a backup aeration system, the one thing that comes to mind is a chargeable battery system like the ones that are used to power emergency light fixtures in commercial buildings.  Under normal conditions the battery is simply being charged and the light is off.  When the power goes off the system converts to battery-powered backup  lights.  You could hook up something like this and if you lost power the battery could be used to drive any number of things including a small dc pump or a fan.  I think the batteries can run for several hours depending on the load.  Grainger sells an emergency light fixture for $173.00 that powers Krypton lamps and supplies 12 V DC.  They sell others as well.  This could be used to power a back up DC water pump or a small motor to drive a fan.  Grainger also sells a 12 Volt DC/1.9 Amp  bilge pump for $30.00. I will give it some more thought.  I suspect that someone already sells an emergency battery backup pump system though.  -Elizabeth

Light,Emergency,54w
Item # 4LB91
Emergency Lighting Unit, 9 Lamp Watts, Number of Lamps 2, Yes, 120-277 Input Voltage, Krypton Lamp Type, Lead Calcium Battery Type, 12 Output Volts (DC)

Pump,Bilge,12 Vdc
Item # 3P996
Pump, Submersible Marine Sump, Hose Outlet 3/4 In., Voltage 12VDC, 1.9 Amps, GPM of Water @ 0 Ft. of Head 8.3, Max. Head 12.5 Ft., Length 2 3/8 In.

Comment by Elizabeth on March 1, 2012 at 10:16pm

Chris,  do you have a drawing of your system?

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