Backyard Aquaponics
A place to discuss aquaponics

OK so I am new...actually haven't yet started. But I don't understand why I would need a sump or aeration.

If I continually pump water from the fish tank through the grow bed and use an overflow pipe I "should" be able to continually cycle the same water through the system. If I put an insert with holes drilled into it in the bottom of the overflow pipe and let it continually "rain" into the fish tank it "should" self aerate.

I was thinking that if I put the fish tank angled so that one edge is lower than the others the "solids" would collet at the lowest point where my pump pulled it upwards as well.

So what am I not seeing?

Don't worry about hurting my feeling by telling me something I don't know:) I know that I am pretty ignorant on this subject and though learning each day, there is alot of real world experience here.

Hi Lex,

Welcome to the forum.

You don't need a sump and probably don't need supplemental aeration but that depends on how many fish you have in your system and what type they are. You probably don't need the insert to improve the aeration either but lots of us do something similar by diverting part of the pump output back into the fish tank for aeration.

For some people, their Fish Tank is higher than their growbeds and they need a sump but if your FT is lower than the growbeds you can skip the sump in most cases.

A couple of other reasons to have a sump (I'm certain there are other reasons besides these) -

1. People who use siphons or timed flood and drain might need a sump because of water level fluctuation in the FT.

2. Helps to reduce the need to top up a system.

Lex,

The simplest system you can have is just a growbed sitting above a fish tank.

Pump from the fish tank to growbed and let gravity return it.

As you have already mentioned, the turning over if the water and the splashing of it as it returns will aerate it.

If you stock correctly (lightly) you won't need additional aeration.

With this sort of system the water level won't fluctuate too much in your fish tank if you decide to run it flood and drain.

A second bed (depending on size) may cause too much fluctuation (a low water level in the fish tank could stress the fish). Switching to constant flood will sort that problem out.

Something to think about is resilience in your system - the ability of the system to take a hit and survive. I've picked up the conclusion from all my browsing of people's experiences across a number of sites that maximising the DO (Dissolved Oxygen) provides a buffer for fish when things go wrong. I had it demonstrated a couple of weeks back...

My wife was cleaning the back veranda and knocked the pumps plug slightly ajar at the socket. I had just fed the fish and didn't get back out there until late the next day. My fish were fine, although ammonia was higher than I have seen it since I started the system. The battery-backed aerator pumps had kept things healthy and not only did I not lose fish, they were healthy enough to be ravenous when I fed them.

So, IMO I don't think you can have too much aeration - whether you use pumps, spray bars, or venturis or all of them - the water will saturate at a certain level of DO and that is good for fish and plants.

As mentioned in the posts above, if set up correctly the water pump and subsequent water return to the fish tank can provide adequate aeration of the water... until your power goes off for some reason... then a back aeration system is essential, as Journeyman can attest to.

The easiest way to do it IMO is with a Battery Back-up Air Pump, such as the Aquapro DC-300... that's what I use in my systems.