Backyard Aquaponics
A place to discuss aquaponics

I have a good system running at the moment which is just a flood and drain IBC chop and flip with a bell siphon. I have 25 Jade Perch in about a 750l tank under the 250l 30mm media of river rock and scoria. It's going great! I want to expand. I have a 2nd IBC that I essentially want to copy, put right beside it and then jam ornamental fish in. The catch is that I want to use the same 3500lph pump that's in the current system. I bought a bigger pump on the basis of expanding, plus it runs an awesome venturi which keeps the noise down right near our window.

I for the life of me can't think of how to manage this without upsetting my current fish but I want to link them together using that one pump. Am I asking to much? Should I just suck it up and do a 2nd smaller pump?

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If you haven't taken a look at the IBC of Aquaponics PDF file that might give you some ideas - it's located here - http://ibcofaquaponics.com/ or you can click the link in the upper right corner of your screen.

Seems like you should be able to pump to both grow beds from one tank and have the second overflow using a Solids Lifting Overflow into the first where the pump is. The grow beds would just drain into whichever tank is below that bed. Is that what you're after?

Wheres the photos of your system we love photos

You will probably have to resize them to upload.

You will certainly need to expand , 25 fish will be too many for your current filtration.

25 jades you will need minimum 3 grow beds 5 would be ideal

If you don't have the capacity as the fish grow you will be battling ammonia and nitrate levels

As suggested above just "Solid Lift Overflow" your second fish tank into your first .

Lift the second one a bit to get the water in the first or partial bury second tank and run water the other way.

A partly buried tank will help stabilise temperature swings and provide a low point to run water from any future expansion beds / tanks

If you want to expand more

Another option for more grow space to handle your nitrates would be a large "Floating raft"

These don't need a huge amount of water flow through them so are cheap to run $$$

Pic below is not one of mine its one I stole

I have heaps of pics that have caught my attention over the years

Make sure all your support structures are strong enough and take into account big rain events

If you don't have paint or cladding on your tanks / grow beds you will end up with Algae x 10

Have fun.

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My System
viewtopic.php?f=18&t=12070

I think so, yeah. I just want to run a 2nd grow bed with a tank for ornamental fish. Otherwise I was just gunna make 2 more growbeds with the other IBC and run 2x 255l drums as a sump while keeping the same amount of fish in the main IBC tank.

It gets difficult when you don't want to drain/move the fish but add to it. If I knew I was going to have this much fun tinkering I would've planned for expansion!

I'll get some pics up later on

You shouldn't need to drain the first tank. You basically just need to set the water level of the second system higher than the first. This can either be by raising the second tank slightly higher or if the water level in the first tank is low enough you can just set the second tank at the same height but with an SLO that makes it's water level higher. Either way the water level should be higher in the second tank and you'll probably drill the tanks through the side for the SLO from tank 2 to tank 1. I would also put in a second overflow a bit above the water level (not a SLO) in case the SLO gets blocked (any water going through this will tell you that you should clean the SLO).

So the flow is like this -

pump in Tank 1 to GB1 and GB2.
GB1 drains to Tank 1
GB2 drains to Tank 2
Tank 2 flows via SLO to Tank 1 and then everything repeats.

I would probably use uniseals where I put the SLO pipe through each tank's side wall. A 2" schedule 40 pvc pipe is a good size for the SLO in an IBC. If you raise tank 2 enough you can go in the top of tank 1 and won't have to drill through the side of that tank. Put something under the where you are going to drill out each tank, otherwise you'll have lots of tiny plastic bits in your fish tank. If you go through both tank side walls and the tanks are close, alignment is important so take your time. Typically you'd use a hole saw for the holes in each tank. Hole saws have a bit in the center that keeps them aligned. I mention this because what I would do is use a long bit that's smaller than the hole saw centering bit to drill through both tank sides at the same time (being careful to go straight and level of course).

Quick question, if I had access to 2x 255l plastic drums, cut the current IBC to make 2x extra beds and plumbed the barrels to the main FT, would there then be enough water to not dip the water level too much for my fish? I took note of @Terra saying that 1 grow bed with 25 fish wasn't enough.

Can I jsut plumb the extra 500l to the main tank to help cope?

Thanks heaps for the info.

Yes you can plumb the extra media to the main tank without any issues. I haven't checked it but you might need both existing grow beds just to run the 25 fish you have - depends on how large you plan to grow them out. Additional grow beds will help but you might also consider additional filtration, like an RFF (Radial Flow Filter) and an MBBR (Moving Bed Bio-Reactor) - The first is for settleable solids and the second is a biological filter. Grow beds do both things so you'd just be substituting a different type of filtration device to do the job.

For the water level question it really depends on how you're running your system. I can say for certain that if you are running the system using Constant Flood where the pump is running 24/7 that all you'd need to do is add more water to handle the extra beds. If you're running timed flood and drain or flood and drain with siphons then it might be an issue. Either of these two methods are designed to have fluctuations and bring air into the grow media. With Constant Flood it's the continuous pumping and movement that aerates the water. With Constant Flood you do not put a weep hole at the bottom of the standpipe in the grow bed since you don't want the water to slowly drain to the Fish Tank (in your case) if the power were to go out.

Hope this makes sense, ask if you have any questions.

Thanks Scotty. It makes sense. I was looking at switching to constant flood for water level ease.

I have a pond cleaner that I get the solids out off the bottom of the tank weekly, so solids aren't an issue and it gives me time to look things over and tinker as well, lol.

I'll flip a coin on whether to plumb in extra water or switch to constant flood I guess. Either way the pump runs 24/7 at this stage with a bell siphon on a 10min cycle.

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You also have the option of running one bed Constant Flood and the other as siphon based flood and drain - that would reduce the fluctuations if you want to compare how they do. Make the standpipe removeable with a weep hole at one end. Use it with a siphon over it and the weep hole down to run flood and drain with siphon. Use it with the siphon off and the weep hole up to run Constant Flood. You could setup both beds this way and switch them however you want.

Wouldn't a constant flood just be a bell siphon without the bell? I think I need to do some more reading on constant flood, lol. Not 100% sure on what a weep hole is or does.

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That's basically it but there is usually one other difference. It used to be that the flood and drain style systems were designed to drain if there was a power outage (or at the end of the pumping cycle) so there was a 1/8th inch hole near the bottom of the standpipe (I call it a weep hole because it drains slowly). I think most flood and drain systems probably still have this but not all.

A lot of people start out with flood and drain style systems but when they expand these they change the whole system to Constant Flood or sometimes just the new beds - basically because Constant Flood doesn't create large water level fluctuations, you don't need a larger tank.

I was led to believe the drain is necessary to prevent root rot. Is this still a thing?

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It's necessary if the water isn't oxygenated in some way. If you're always moving the water and there are no dead spots in the grow beds, then root rot shouldn't be an issue. Timed Flood and Drain setups should probably have a weep hole. For siphons that are run all the time and for Constant Flood systems which run all the time you shouldn't need one - power outages are hopefully rare events. Siphon systems that are always running have a tank sized for the fluctuations in water level caused by the siphons - even though they don't have to have a weep hole, it will allow the beds to drain in a power outage so I would put a weep hole in. I think I'd list the need for a weep hole like this -

Timed flow (with or without siphons) - weep holes are necessary
Continuous flow (with or without siphons) - weep holes are optional but if you have enough holding capacity in your sump tank it might be of benefit in a power outage .

In a power outage, is it better to leave the grow bed filled with water or empty?

That's a good question and I'm not absolutely certain of the answer. For short power outages of a day or less it's probably not going to make much difference. If the beds are designed to drain then I'd drain them, if not then I'd leave them full.