Backyard Aquaponics
A place to discuss aquaponics

As I have discussed in another thread, i just came to own a 300 gallon tank.... It has totally thrown my whole original design out the window and I'm already facing many challenges.

First a little bit about the system I'm designing. For the main fish pond I'm using a 300 gallon tank. For the grow beds I have room(horizontally) to fit about 6 blue barrels (sitting vertically), or about 3 half blue barrels laying vertically. I'm also planning to use vertical grow tubes eventually. I have a pump with sufficient GPM and head to provide for the system. I dont want to cycle the pump if possible and I only want to use one pump. In the fall the system will be drained and cleaned. Then the pond in the ground will be converted to an underground storage cellar to store food from our garden. Then in the spring after the danger of freezing, the system will be restarted.

One member here suggested that I use 55 gallon blue barrels stood up vertically to use as the grow bed. It sounds like a great way to get enough bio filter material and surface area, etc that will enable me to grow more fish in the pond. I was just reading another thread and it made me remember that you have to provide oxygen to all of the biofilter material in order to prevent sludge build up.

Well how exactly can I provide oxygen throughout the entire barrel if it is constantly filled with water?

I dont want to do a fill and drain cycle. Partially because it would take a lot of water out of my fish pond to fill the barrels. I could always get a large water storage tank that it could draw from, however I dont have the money for another tank of that size or anywhere to put it.

If I cut the barrels in half to help minimize the amount of biofilter that doesnt receive oxygen I drastically cut down the amount of biofilter material used to remove ammo....

Ok so after thinking about this as I was typing I had an idea... What if I had the supply line from the pump go directly into each grow bed at the bottom of the barrel, then it pushes the water up from the bottom to the top. It will end up with a few dead spots, but nothing compared to top supply and top return.

Remember that a grow bed when filled with gravel is only going to hold 40-50% of the water it would otherwise hold. So 6 full size barrels set to flood and drain will only cause your tank to fluctuate by perhaps 50%. That is a kinda big fluctuation but probably ok if you had the barrels running with auto siphons. I can understand your not wishing to have the fluctuation but you will get far more bio-filter capacity from your gravel if you do flood and drain. Otherwise, you need to add lots of extra aeration to the system.

I'm not a big supporter of using blue barrels unless you get them for free. Problem with them is they require extra space, support, and plumbing. You can get more grow bed for you buck by using pond liner provided your site suits such things.

You could use a couple of barrels as a sump to offset the water taken from your fish tank.

2 Growbed set-ups,,,pump to one wait for drain,,,then pump to other,,wait for drain,,etc,etc.
For reliability rather than a"switching valve"..... 2 pumps and timers.
It's one of many options.

"Ok so after thinking about this as I was typing I had an idea... What if I had the supply line from the pump go directly into each grow bed at the bottom of the barrel, then it pushes the water up from the bottom to the top. It will end up with a few dead spots, but nothing compared to top supply and top return."

Interesting idea but I think you may have problems with root rot and the sludge will still accumulate in the GB's.
EB had a multi storey blue barrel system with I think loop siphons, provided they wern't in sync this would allow you to use six half barrels on a continuous flow pump with F and D.

This method works great for lightly stocked ornamental ponds. This is kinda how they do the bio falls or filter falls. I doubt this will work well enough for a heavily stocked AP system. People running continuously flooded grow beds without lots of air stones in those beds, seem to struggle quite a bit more with their bio-filter capacity. On the flip side, gravel with a constant trickle flow might work for growing plants but has the similar but opposite problem where not enough of the gravel gets wetted and therefore doesn't give much bio-filter for the volume.

You would probably get more bio-filter capacity for your available space if you were to use a couple of those barrels for "sump" tanks and the other 4 as upright grow beds on flood and drain. Good luck.

Thanks for all the replies.

So it sounds as though I need to look at doing a fill and drain system to make the best use of what I have?

It kinda sucks because I was hoping to keep the controls simple....

How about if I run a single pump and two electric solenoid valves?

I could run the pump continuously and use solenoid valve #1 to control the fill and drain cycle on grow beds 1 and 2, then use solenoid valve #2 to control the fill and drain cycle on grow beds 3 and 4.

Each solenoid would be controlled by a timer set to a fill and drain cycle of say 1 hour fill, 30 min drain... or whatever it turns out to be based on flow rates. Each grow bed could just have an overflow drain to drain back into the pond when it is full.

There would be continuous water flowing through the gravel and watering the plants, the drain rate would just be faster than the fill rate.

If I did the system on a 2 system cycle like that it would only fluctuate the level of the pond by 50 gallons if we assume it only takes 25 gallons to fill the barrels when they are filled with gravel.

Anyone see any problems with running a system like this?

The only problem I can see now that I have typed that out is that I cant find a 2" electric solenoid valve for cheap....

What if i used manual valves and just drained the system each day? Will that provide enough new oxygen?

I dont have room for a sump

Howdy BR:

Can you post a picture of the site? How much vertical space is available?

Instead of solenoids most here use siphons either a pip-in-pipe kind or loops. Each barrel would have its own siphon, so the gravel can be flood and drain using just the one pump and no other kinds of solenoids, switches, or other.

Like TC said, if you have a few beds each with their own siphons it is rare though possible that all the barrels will be full of water at one time, so on rare occasions you would have the worst case scenario of the fish tank being down the to the max drop. On average if you look at all the beds some will be nearly empty, some nearly full, some in between. It will balance out that your beds will be 50% full at any given time, so your fish tank drop will be half of the worst case drop, most of the time.

I have four 25 gallon beds each with a siphon, and this moderates the water level drop. You do have to plan for sometimes having the max drop at least for awhile until the beds go out of sync again. It can take awhile for them to drift into and out of sync.

HTH!

BTW I did a poll one time and it seems that most people see the water in a bed being 30% or 40% of the total bed volume. Once you have plants the roots take up additional space between the gravel, reducing the water volume required to fill the bed.

Do you have a link to a diagram of a siphon system?

does it continuously syphon?

I cant upload a picture of the sight, however I do have a 3D rendering of the space.



This image shows an option of 8 additional 3 gallon grow beds to add an additional 24 gallons of biofilter. I would supply them with the water being siphoned from the large 55 gallon barrels. If I did it this way and the water just drained from the 3 gallon beds into the pond would it provide adequate air supply into the water in the pond? Or should I stick to a direct siphon to make sure the air gets mixed in the pond water? I want to go without an air stone.

Hi BR
Looks like theres a bit of room on that fence for something.
If the rendering is accurate, i`d be a little concerned about runoff from the grassed area..i`d dig it up and replace it with gravel, aka Daves Aqua-patio

You might put a 55 gallon sump in the ground under the barrels.

In my system I use pea gravel and I am able to fill 3 400 gallon tanks of gravel from a single 400 gallon tank. Of course there is no water left in the sump. So the small pea gravel displaces about 66% of the water.

What do you mean?

Should I be concerned about water run off into the pond or pond water into the grass?

I dont fertilize my lawn with chemicals if that is what you are worried about, I use manure from the rabbits and worm compost tea.

You want the lip of your Fish tank to at least be a little above the ground so that you don't get dirt or whatever running into your tank. Even if you don't use chemicals, if your fish tank is turning into the low spot in the area and all the run off from a heavy rain is going into it, it isn't so good.

I would avoid solenoid valves as they can get gunked up. You can do flood and drain without any timers, solenoid valves or anything tricky. You just need to look into auto siphons, bell siphons, loop siphons, or flouts. Lots of info about all those on this forum if you can find it. Some siphon threads are sticky so should be pretty easy.

To avoid needing a sump and minimize the fluctuation of the tank level, you could cascade the grow beds. This does work but involves vertical support to put a couple grow beds higher than the next one. I am essentially doing this where I have two grow beds that are up on a stand draining into a grow bed that is on the ground which drains into the tank in the ground. This method is a bit tricky but not too bad and definitely better than fancy high tech control systems.

Some benefit of continuous pumping, if you have a pump big enough to have some bypass water splashing into the fish tank, you don't need extra aeration, and you don't have to worry about timers or valves failing. You do need a pump that can handle being always on and you want it to be energy efficient so it doesn't cost you and arm and a leg on the electric bill.

Anyway, for your space (this is assuming you already have or are getting the barrels and small grow beds free. I would recommend something else if you don't already have these or they are not free.) I might put the furthest two barrels up on some support so they are higher up. Then the next two barrels on a support a bit lower than the first two barrels and cut these two barrels about 14 inches shorter. (if the barrels had solid tops, you can flip them over and use in place of some of those 3 gallon grow beds.) The set up the loop siphons so that the tall barrels drain into the next barrels down and those into the tops (and 3 gallon beds) that can drain by auto siphon directly into the tank. Then perhaps you can do another cascade over on the other end where the graphic shows nothing.