What are your throughts on Murrays CHOP2 system?

[Chris Johnson]

http://www.ecofilms.com.au/2010/10/28/aquaponics-chop2-revealed/

[TCLynx]

Fine design.  However, if feeding something like NFT pipes, I like a clean water sump where all the water has gone through a grow bed so I don't have to deal with supplemental filtration to feed the NFT channels.

[Chris Johnson]

Thanks TCL ! It's definitely up for consideration, and I don't think NFT is something I'll touch, if anything I'll do some floating rafts at some point.

I like that I can turn off the grow beds at night especially in the winter time when they will lose the temp. But it's something I can visit when the time comes.

I've followed your systems and must say I'm impressed with your progress in AP!. Thanks for hanging out in the forums.

[Alfio Contarino]

Hi Chris,

For the winter have you ever consider using a compost heater?  I’m about to build on this Saturday.   Not as fancy as the one in the link but a basic drum and hose in the same fashion to heat the tank in winter...

 

http://permaculture.org.au/2010/01/11/free-hot-water-from-compost-w...

 

[TCLynx]

Instead of turning beds off at night to conserve heat, I think that switching to constant flood might be a better method to keep the gravel and water warmer.

[Rob Torcellini]

I’m full of opinions today….or I don’t feel like doing my real job.  ;-)

 

I'm not a fan of letting the solids accumulate in the sump...they could become anaerobic. I rather let the solids run into the growbeds and let the worms take care of them.

 

For a greenhouse user’s standpoint, you shouldn’t use compost INSIDE a greenhouse.  You’re just inviting pests and disease in….plus that space is too valuable to waste for that….I rather grow plants.  I keep all my compost outside and let nature do its thing.  There have been a few studies done on using compost as heat….if you have a LOT, it can work, but the typical gardener doesn’t generate enough compost to warrant the time/money/space to generate a little bit of heat.  I’ve even seen people bring in manure and compost to add to their system….why waste the fuel/time on it?

 

I took a quick peek at the compost image….many people may tell you not to add cardboard/newspaper to your compost.  Even though it may have cornstarch as a binding and soy ink for the print….there is still a ton of chemicals in the paper making process that will leach into your compost.

 

I shut down my beds at night…even over the winter.  If you’ve seen my YouTube videos (search for web4deb), I show a bunch of stats on my greenhouse over the winter.  When the beds shut down at night, the will slowly lose their heat and when the system starts, it’s very evident that the overall water temp of the system can drop a few degrees once all the beds have flushed through again.  However, if I continue to run the beds over night, I will get the same amount of heat loss in the water during the night.  So, my findings are that if you stop the system, or continue to move water through, it makes no difference in the overall water temps…but the bed will stay at a slightly more constant temp by always running the system.  The benefit by shutting down is I save a little electricity by not running the pumps.  I’m in a much colder climate than TC is.  ;-)

[TCLynx]

so true Rob.

 

And to run constant flood, you are going to be running the pump constantly and use more electricity.  By keeping the beds flooded, the air doesn't get to sink down into them and cause the chilling effect of the heat exchange of the cold air getting down in there to chill the gravel to then chill the water more.  However, doing this is probably only going to save a few degrees and will only likely be effective for certain marginal situations.

[Rob Torcellini]

agreed

[Chris McMahon]

I am building a chop 2 right now so I will let you know after I run it awhile. I don't have to worry about cold weather here in the desert of sunny southern California.

 

[Chris McMahon]

I turned the system on yesterday and it's running. It only took minor adjustments to get the siphons working. The build isn't too difficult and I have a lot of grow space. 3 x 4'3" by 3'4" beds. One thing I didn't get on the DIY system DVD is how to add three more beds. They said those plans will be on the DVD but they are not there. I suppose I would need another pump and rebuild the same system again without the extra fish tank. I have a 275 gallon fish tank now. I think it's holding more like 250 gallons. I am working on getting the chemistry right now. I expect to run the system for a week or two before adding anything. I want to get any kinks out.