Backyard Aquaponics
A place to discuss aquaponics

Hello everyone,
I'm in the process of building a small system with a 20 gallon fish tank with a 1:1 grow bed ratio. I was originally going to try an ebb and flow set up but didnt consider somethings in the process. I dont want a sump tank so I am worried about fluctuating water levels in the fish take since it's 1:1 it would essentially empty the tank every cycle. so I decided a constant flow may be a better option. now here comes the question. How tall should I make the drainpipe? From what i have found 1-2" from the top of the media is recommended. What do you guys think???

I am curious to see what others think about this. One thing I find with media beds is occasionally you can have an issue with floating media and as a result it wont actually support your plants properly. Although usually all you need to do is lower your water level or increase your media to resolve this issue. But as to 1-2" below the level of the media, I think that is a good starting point.

I am in the processing doing almost the exact same set up here. I also came to the conclusion that a constant flow would probably work best for me in order to not drain my fish tank. I got coco croutons as my media and now i am wondering if I will even be able to plant in them or if they are just going to float around. Does anyone have any experience with these and/or suggestions on how i should set up my GB?

Floating media isn't something I have considered. I kinda thought that they were designed to prevent that. From my research Hydroton seems to be the best. Does anyone disagree? is there something better??

Its virtually impossible to do 1:1 ratio when you are doing flood and drain with a bell siphon... As you have found when you do this your entire fish tank will be drained, thus demonstrating the whole point of a sump for some systems.... The sump is the only tank that would have a fluctuating water level.

So, just use a much smaller growbed than your fish tank... For a 20 gallon aquarium maybe only use a growbed of about 5 gallons for example. There will still be a large fluctuation in the water level within the fish tank but it wont be terrible enough to disrupt your fish (it could only affect the density that you pack your tank with fish).

As for my comment on the floating media haha

I had an experience where I used some sort of recycled glass material. It looked like lava rock almost. It floated terribly. I have had some instances with the hydroton floating as well... However, I don't think I used enough in the growbed. Pretty sure you just have to make sure your water level is below the top of your media level by a few inches and you will be fine.

We call this Constant Flood (even though the water is flowing) as opposed to constant flow and you want the surface to be dry so 1 or 2 inches below the surface for the water level sounds about right. You can always shorten the standpipe so start out higher until you find the right level. You won't want to have a hole in the standpipe since you don't want the water to drain into the Fish Tank during a power outage like you would with Siphons or timed Flood and Drain.

Regarding the floating media - that does happen but over time they settle in (a few may float after that but not many). If your water level is right this won't be a problem after the initial period.



Haven't used them but I would expect them to breakdown over time and need to be replaced. As far as floating . I'd consider returning them if you haven't opened the bag even though they probably will work. At some point I'd expect them to compact to the point they have to be replaced and you might have to re-establish the bio-filtration. Others have used Coir and it's worked - I'm not sure what they had to do to get it to work.



Don't forget you're only filling the spaces between the media in the growbed so you'll only really be using about 40 percent of the fish tank water or less. Still what you say is true for needing a sump or enlarging the fish tank. Using Constant Flood avoids this whole fluctuation issue because the water level remains the same in the Grow Bed and the Fish Tank - the water is just pumped around in a loop 24/7 to maintain aeration.