Wednesday, July 22, 2009

Back in business

I'm back in business. So, the rubber containers ("buckets") that I've been using had this pre-installed metal-threaded bulkhead fitting/outlet that I used as my drain. Problem was that they were only about 1/2" diameter, so thin, that a single piece of gravel could get stuck inside it and clog it up. That was the cause of the disaster.

So, what I had to do was to try and push all my hydroton/gravel to the other side of the bucket while attempting to not kill any plants, remove the metal-threaded bulkhead fitting, drill out a larger hole, and then install. I used 1" pipe this time, probably still not wide enough, but a major improvement. I've heard the occassional piece of hydroton getting sucked clean through, so I think the risk of clogging is lessened.

I also followed the recommendation of every single other aquaponics person in the universe and put in a standpipe with the cut out "V" at the top. I don't understand why that makes such a difference, but trust me, it does! The suction is now pretty impressive. I drilled plenty of holes through the standpipe to allow the water to fill in and drain out before it even gets to the top "V", and given that my water is running constantly, I found that the more holes I had, the more flow I could give the bucket without overtopping the standpipe and flooding the plants.

From everything I've read, people use the flood/drain system to ensure that the roots have enough oxygen to avoid root rot. Given that my pump is also operating the waterfall for my pond (more of an aesthetic purpose), I choose to let my pump run all the time. I find that the plants seem to do well enough that I don't notice the difference. Maybe they'd be even bigger if they had some time to breathe fresh air! Given that the water doesn't stay all the way at the surface, part of the root system is always getting some oxygen, so that should help.

My next system will likely be aquaponics only, so I'll try out a timer and do a flood/drain type of thing. I'm looking forward to not having to run the pump 24/7 from an electricity-use standpoint, as well.


Jimmy said...

Hi Brian

Check out this site. His bell valve design for flood and drain is amazing ....

Andrew said...


Check out as well. I have built my own system using IBC's and siphons. You can use your existing fittings and waste pipe from building sites. Top of stand-pipe to be 50mm below media surface, keep about 30mm between top of stand-pipe and 50mm diam siphon tube!

gemmell said...

Another tidbit, cut a bit of PVC into a C shape - you then have a height adjustable stand pipe.

like this

I can also rotate that bottom fitting with the hole in it so that i get an adjustable flowrate out too.

Also, keep a close eye on those metal fittings - AP tends to be acidic, so if you're pH is less than 7, it's going to start eating away at things like brass or zinc plating (I think stainless steel is the only one it wont). Heavy metals are really bad for fish - they die, slowly, over a period of months. I know this because it happened to me.

Brian Naess said...

Thanks for the heads-up on the heavy metals! As it stands right now, I'm not using any of the metal outlets on the buckets anymore, since they were too small. All my future buckets will not only be metal-free, but also not be as deep.

Thanks to all for suggestions about siphons. I'm going to try Affnan's bell valve design this spring. I think I'll get much better results with a flood/drain system, than my current system with water in it all the time.

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