Crawfish, Crawfish everywhere !!!!!

[keith_r]

not if you feed them enough..

[JCO]

I'm not writing at this moment but I am at least thinking about it...it's off to work in a minute though.

[15mules]

I may try them in one of the smaller test systems I am planning. More available feed sources may very well be the key to keeping them from eating the plant roots. I would imagine if the migrated throughout the whole system it would not really hurt anything, as long as they did not eat the plant roots. The ones that made it to the fish tank would only become food for the fish I suppose??

[keith_r]

yup..
crayfish are "detrivours" and usually only consume dead/rotting things.. a good sinking pellet (like catfish food) is an appropriate feed..i don't see baby crayfish being able to survive very long in a flood and drain growbed, unless you have a void (no media) in the bottom of the bed and don't flood all the way..
if you're only doing DWC troughs, you'll need some filtration, some young may get trapped in the filters but they would be fine until they outgrow the space
and yeah, the fish will eat them if they can fit them in their mouths

[15mules]

My DWR system does not have a active filter, or seperate filter media etc., only FT pumped to grow troughs then back to fish tank. Plenty of aeration close to the bottom to keep the solids from simply settling in the FT and low density fish numbers, to only produce enough nutrients for the plants. I do not see the profit in trying to produce high numbers of fish.

[dead_sled]

The filter is not only a place to collect the solids, it is a place for the bacteria to colonize and process the ammonia.

[15mules]

The bacteria will colonize on the under surface of the rafts, the sides of the grow troughs, and more importantly on the plant roots themselves. This method has been well proven to work in systems that have been in commercial production for a number of years.

[keith_r]

if you do have solids buildup on your roots, your plants will start to suffer from "root rot"..suffocating them slowly
but if your roots are nice and white, then whatever works for you!

the real "ratio" to worry about is the amount of feed to surface area where bacteria will be growing..
it hasn't been proven commercially by anyone using aquaponics where you have actual solid waste.. (i've yet to see a "successful" commercial ap system - when i say commercial ap, i mean supporting a business with just sales of veggies and/or fish, without having to offer training courses or "kits" or other sales to support the business)

on the other hand, i've seen numerous ap dwc (or dwr as you call it), fail because they did not take into account removal solid waste

it works in hydroponics when all the nutrients are in solution...and you aren't counting on the ammonia to be converted to nitrites, then to nitrates by bio-activity

[15mules]

Kieth,
I hear you, and this is part of the fun in AP, proving and disproving our believes by actual trial and error. I look forward to getting my system up and going next month, so I can do just that. prove to myself what I believe is correct, or prove what I believe is incorrect, as long as we can admit our mistakes and move beyond them and do better, this is what matters. Like I have heard before "The only person who does not make a mistake is the person who never does anything". Make the best decision we can based on the best available information we have at the time.

[Roger L.]

I was planning a raft system to to raise strawberries in and that brought an ideal to mind. Could I make another raft strictly for raising crayfish? I could add in some rocks build in cubby holes and add small clay pots for hideaways. This keeps the separate from the fish so no cohabitation problems. The water level would need to be a little higher and I believe I would work an expansion place to continue the raft. I was thinking about making this out of 6" or 8" round tubing with the top open for access. What does everyone think?