Originally Posted 4th-March-2009

Well things progress, the water temps are 72 degrees (22C) in the fish tank and the DWC tank runs 64-68 degrees (18-20C). Ive added 2 small handfuls of Urea over 4 days and a small handful of powdered seaweed to put some nutrition in the system. On Monday I also added 6 small Koi (6 inches). Two of the stupid things jumped out of the tank last night! That was a waste! Now I have a foam cover over it.

Water tests, since I filled the system a week ago, show no change, PH 7.0, ammonia, nitrite and nitrate at zero. TDS 430. Ill add another handful of Urea tomorrow and wait a couple of days. I have a few small lettuce seedlings in the grow beds and planted a few other seeds as well.

I went through a number of configuration changes that others can avoid.

When this all started, I downloaded the Barrelponics manual http://www.fastonline.org/images/man...ics_manual.pdf And picked up some related DVDs. I also purchased materials from the backyardaquaponics.com group and most recently Murray Hallams Aquaponics Made Easy, and the Nelson and Pade Aquaponics on DVD, among other things (talk about over analyzing). All these were useful for different things. For a simple system using 55 gallon barrels get the BarrelPonics Manual, is free. For a two pump, float switch activated, mostly wet system backyardaquaponics.com has good material and nice fish discussions. Murray has the best for the mostly wet single pump auto siphon systems. Nelson and Pade is a higher level look with an overview of various system configurations , including the use of systems with no grow beds and just DWC rafts, but it lacks the practical details needed to actually build a system.

I originally started with plans for a system using a 275-gallon Tote pumping into a dump tank that emptied into gravel beds made of 55 gallon barrels that drained into a sump that pumped back into the fish tank. (Just saying all that was a mouthful) In the end, I found a two pump system has the potential to empty fish tank if the sump pump failed or float switch got stuck.

Then I considered 2 pumps using float switches to flood and drain the grow beds periodically through intermittent pump action. Finally, as a result of discussions on the various aquaponic forums, I settled on a single pump system with the pump in the sump tank. Water from the sump is pumped to the fish tank, which overflows into the grow beds and DWC raft, the gravel beds auto siphon and drain back to the sump.

I divide these methods into Mostly Wet and Mostly Dry systems as follows:

Mostly Dry using either pump cycling or dump barrels with siphons or flush mechanisms. In this system, the beds fill quickly and then drain out all the water slowly. Drain time is controlled by the size of the drain opening, which is in the bottom of the grow beds. The downside is that it requires more pumps and/or tanks. Cycling a pump will cause more wear than continuously running a smaller pump. The dump barrels operate on a continuous pump filling the dump barrel that periodically flushes into the grow beds and an intermittent pump in the sump to refill the fish tank. The level of the fish tank goes up and down.

Mostly Wet a pump or pumps in the sump tank run continuously pumping into the fish tank. The fish tank maintains a constant water level with an overflow to the grow beds and raft. The beds fill slowly (hence the mostly wet). Then drain quickly when the bell siphon kicks in. The bell siphon tends to leave 1 (25mm) of water or so in the bottom. This has a beneficial affect that if the pump goes out, the plants continue to have water and the fish tank stays full. The pump can be a smaller pump that runs continuously, no cycling. Resulting in less wear and tear on the components and less points of failure.

I have considered putting in a float switch to shut off the sump pump in case the water level gets too low (as I hope to have red claws in my sump tank). We will see. Ill talk about backup pump operation later.

Now Im just impatient for the system to cycle and for the State Inspectors to Issue my permit so I can get some fish!

My system is similar to the CHOP system here - http://www.aquaponics.net.au/Chops.html

That process of obtaining permits will be my next installment.

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