Backyard Aquaponics
A place to discuss aquaponics

Hello everyone my name is Niklas Anderson and I am new to the forum. I am looking forward to learn as much as possible through this forum and its members.
I discovered last year my passion for growing and started off with a hydroponic system built from parts in the shed. After a few harvests I realized that this was not the optimal way to grow, too much wasted nutrient and energy. I found this website and began to read, the next day I built my first ebb and flow aquaponics system witch I have used as a seedling starter for my 180+ square foot raised grow bed. I also volunteer most thursdays at an organic farm that implements some biodynamic practices.

I am currently designing a deep water culture system for my back yard and will hopefully be ordering the supplies needed within the next month.
The grow bed will be 25' long, 5' wide, 18" deep, will hold 1402.5 US gallons, and 125 square feet of grow space. I have some questions
1. Is it possible to over filtrate the system?
2. Is there any specific material that I should use for the GB liner? HDPE ok?
3. Would a 700GPH commercial water pump be sufficient?
4. Is it possible to over oxygenate the system I have been looking at a 110LPM commercial air
pump?
5. From what I have read I should have a 1 to 1 ratio grow bed to fish tank is this correct?
6. Is a 55 gallon sump tank enough? Or do I even need a sump tank?
7. I will be growing tilapia, I remember from somewhere that I should have 2.5 gallons for every
full grown fish? Should I over stock when I get my fingerlings incase of mortality rates?

I want to get this right the first time so please any and all information and ideas for creating the perfect system will be greatly appreciated.

Sincerely,
Niklas

Welcome. I'll just answer what I can quickly.

1. Yes, but unlikely. Are you planning any extra filtration other than the growbeds? If you have water plants in your system they can remove lots of nutrient and you may not have good plant growth in your growbeds for this reason.
2. 45 mil EPDM is probably the most popular but there are other options. HDPE might work if it's thick enough but you might need to be more careful than with EPDM. For more information you might try -
Swanberg's thread (DWC system) might have some information and TCLynx (tower and DWC) is using a different sort of liner for some of her systems. DecalsbyJT (aggregate) has some wooden growbeds and goes through the build in his indoor system thread.

3. Not enough info to tell you this. Don't know the height you will be pumping to or the type of pump. Most people try to pump the volume of the Fish Tank once per hour but this isn't set in stone.
4. I'm not sure about this.
5. I wouldn't worry to much about this ratio.. The most important thing is you have sufficient filtration (growbeds or whatever) for the number of fish your system carries. It doesn't take many fish to get lots of plants but if you have a huge volume of water and only 5 fish your plants won't grow well.
6. Not enough info for this one either since we don't know how you're going to run your system - Constant Flood, Timed Flood and Drain...
7. Don't overstock - you have a new system and the filtration needs to get established. I haven't grown Tilapia but I hear they breed so you'll probably wind up with extras

This thread might be useful - http://www.backyardaquaponics.com/forum/viewtopic.php?f=12&t=6646

If I were going to set up a new system I'd run Constant Flood and CHIFT PIST (Constant Height in Fish Tank and Pump in Sump Tank). This would allow a small or no Sump Tank and very little fluctuation of water height in the Fish Tank. This also takes the pump out of the Fish Tank where the fish can knock it loose. You might want to look up Solids Lifting Overflow (SLO) as well.

+1 on Scotty's point 5 answer....growbed volume (filtration) to desired fish stocking/feed rate ratio is what maters most. Dont concern yourself with ft to gb ratio

+1 on his point 7. Additionally, you shouldn't have to expect mortality if ur fingerlings are a respectable size and you take your time/care with things.

I got my first batch of "real" fish in April. I've only had two deaths, and these were due to fish jumping out of the tank! (knock on wood). If I had have secured around the top ofthe tank properly those poor little fellers would still be with us....at least until November

Welcome Niklas

thank you for the fast replies I appreciate it. I will try to repost this afternoon with all the info I have for the system and try and do a sketch up of the system and my planed filtration system.

Welcome.

We all love pictures!!