A bit about me will help people understand my point of view. I was raised on a farm and went to college for horticulture but ended up dropping out due to loosing my full time second shift job. Became an electrician helper and in this state at that time became a licensed electrician three years later without proper schooling so limited to residential work. My hobby has been raising tropical fish since I was very young. I thought my dream was coming true as I got a fish room up and running on a central filtration system. I fell at my factor job and broke my back and lost everything including the ex wife. I have 200 fish tanks in storage with two currently running one with aquatic turtles and one with 4 2-3 inch koi that are the start of my aquaponic system to be. Green house is build but not covered in plastic and was limited on size due to codes here at the house. I plan to get the system running and learn before building the real system at the farm 40 miles away. I know about battery back ups and multiple pumps and the like the green house at the farm will require as I will not be there daily. I am currently growing produce for farmers markets in my area. Our main cash crop is blackberries. I have three ponds at the farm which will be part of my aquaculture plans. My plans are to breed koi or other goldfish species so that I do not have to heat the green house much if at all in the winter months.

I have been reading and studying for a few weeks on the actual system for aquaponics. Budget is causing me problems to follow the guidelines given in the books and in the 101 series here. I plan on the green house here at the house(10X11.5 as it had to be under 120sqf) containing the fish tanks(2 IBCs) and the gravel filled flood drain beds so that I have a constant cycle. I am planning to run a long DWC raft system during the growing season with a catapillar or dog house type hoop system to extend the season.

Now the questions:

1) Is 6 mil plastic sheeting durable enough to use to line a gravel grow media bed? I have had no luck getting used signage as one book said was readily available. Plan is for basil, rosemary for gravel beds so plant one time each spring and only need maybe two years max out of this system.

2) Can you get away with using 2X8s which are only 7.5 inches tall for a DWC trough? Lettuce and other greens are the only things going into the raft system. The cost of 2X12s is not in the budget as this bed is going to be 40 ft long and 4 ft wide. I know the plastic sheeting will work here as there is nothing sharp about foam rafts and if it just last a year before upgrading the liner I will be fine with that. If the money will allow I do plan on using 2X10s but fear I maybe needing to go down to 2X8s.

First box of koi fingerlings(1-3 inch and about 150 count) will be here in about a month. I have a few 40 gallon breeder fish tanks to be used if fish arrive before the green house system is complete. I have one bag full of hydroton as it was used for dart frog tank that is no longer in use. I packed a box filter full and have it cycling with the 4 koi to help jump start the cycle when the box of fish arrives. I plan on putting a few sailfin mollies in the DWC part to eat mosquito larva but doubt there will ever get to a pound of them in a season. I have done both aquaculture and soil farming on large scale(22 acres tillable soil on farm). I have even done a bit with hydroponics when I worked on the weekends at the college green house years ago(gutter system which I think is now NFT). My thinking is that by combining my knowledge in these fields together I will have a leg up on most new to aquaponics but I maybe totally wrong.

Thanks ahead of time for your help, John