Backyard Aquaponics
A place to discuss aquaponics

The "am I buying a dog" thread got me to thinking...

My system has been running flawlessly but I came home from work the other day and I had a pump that failed. Luckily I keep a back up pump, even though I know my system is new, I would know it would happen at some time. They replaced it under warranty with one day shipping and now I have another back up.


But..... what if you cant check your system everyday like me, what if you work in the oil field and work two weeks on two weeks off, or are gone on business.

What do y'all do to have a back up plan?

Just curious as to ideas if you are gone and cant get back and something goes haywire...

Hi East,

I just posted in another thread to you but this seems a better place...
you could run two pumps each at about half the capacity you need, therefore if one fails the other will keep going and circulate enough water to the FT to keep fish alive and Gbs... however this becomes more complicated when you have towers or tubes like I know you have as the loss in flow can result in no flow to the pipes or towers sometimes... but at least you don't lose fish and GBs.
Also relying on pumps for aeration alone is not always that great especially if you have a pump failure so if you have a pump and air pump then either one will keep your fish alive for quite a while... although air alone will not help too long if you are using an auto feeder like yourself as without circulating the water you will quickly get an ammonia spike (within day/s)
Personally I run 240v pumps and 240v air pumps and then in case of power failure I have an auto switch that switches on a 12v air pump running of a 120 ah deep cycle battery... I also have a 12v pump which will be connected to the same battery and a timer to circulate some water but I have not connected that yet. The air pumps don't draw too much power so a battery can keep it running for days+ but most pumps draw more watts and probably need to be on a timer to conserve battery and only keep the water in the FT somewhat fresh and the GBs alive..
Ofcourse my backups don't help in case of mechanical failure of pumps unless it trips the power and that is why it is good to also have the air pump and if possible two water pumps at the same time (two pumps will use more power than one of equal capacity though and is overkill for anyone who sees there system every day or other day... but if you go away for periods it may be worthwhile... or worth switching on when you go away... a good use of a spare)
Remember if you use two water pumps that feed the one pipe you will probably need a non return valve as otherwise when one fails the water from the other pump may flow out the non function pump... in a CHIFT PIST system however you could just run two seperate lines from each pump to the FT to avoid that hassle.

Power failure, pump failure, plumbing failure is best detected by monitoring the water flow since lack of flow is what we are really worried about. You can do this in as many ways as you can design different aquaponics systems. Go all out and get a flow monitor with relays, an EC meter to detect dry contacts on the sensor, or scavenge a micro switch you convert into a flow/no flow detector. Have the detection system running on battery and when it detects no flow it can activate your completely separate backup system.

It's expensive but you plumb a second pump in parallel with a check valve after the outlet. Have a flow switch on the outlet of your main pump, going to a relay which leads to the secondary pump. If flow drops below your preset level, pump #2 kicks on. If #1 comes back online, the flow rate increases which shuts off pump #2. You can also do this with 2 float switches placed in precise spots in the sump.

For air it's the same deal, just substitute the flow switch for a pressure switch.

Hope this helps!

Well when you start thinking about the things that can possibly go wrong, it is very easy for one to over engineer something very basic. And very often over engineering something brings new risks that you need to mitigate again and you add more and more until it becomes a very complex system. Put simply, I don't have a backup system for the water pump. Air, I do because the fish need air more than water quality. Doing a risk assessment, what happens if the water pump fails and you are not around to detect that failure? Consequence is that there could be multiple fish fatalities if the water quality gets bad enough. Frequency of the water pump failing when you are not around? The answer to this question could be different for different people. For me, we don't go away much, and I only had a water pump failure once in 2-3 years. I think with the consequence and the frequency, I could possibly say that the risk could be between intermediate and low. I don't feed the fishes if I go away for two weeks and I tend pay more to buy a reliable water pump like Laguna. Those two are additional layers of protection that I can take credit for. So I think I would class the risk of a water pump failing at the same time when I am not around and for the water quality to get bad enough to affect the fishes due to no feeding, the risk is considered low or ALARP (as low as reasonably practical).

And since you might laugh at my way of reasoning, you should probably know that many industrial facilities and gas plants are built with the same level of risk assessment and mitigation. Nothing is built to make it extremely fail proof.


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ALARP. That just rolls of the tongue. I now have a new word in my working vocabulary.

As part of my job I build, monitor and maintain maintenance strategies and life cycle componentry for heavy mobile equipment. In its raw sense think about every main component on your car has a hour meter and when that component has reached its life expectancy it can be replaced. In the mining industry having components monitored and replaced in a planned manner prevents unwanted downtime, damage and in some cases injury. The frequencies defined for certain components are decided from a collection of OEM recommendations, history and experience. The reality is that there are still unexpected failures, damages and exessive wear beyond control but thats just something that is excepted.

Ive often thought if this methodology would work for critical AP components like air and water pumps but Im not sure if there is enough valuable information out there to come up with something even ball park valuable. There are so many models and designs of pumps and every situation is different when you take into climate, weather, load, design etc etc. In my own experience and from what I have read over time is that in most cases water pumps deteriorate rather than straight up fail.. which would have you think that a periodical change out would be void.

I take the attitude that since it is reasonably practical to plumb a second pump in - and I have one spare so it is there if I need it, so putting in another 3m of pipe and a timer is reasonably practical and therefore should be done. You're right Ivan it depends on the liklihood - I'm away quiet a lot so my likelihood is higher.

case in point - last weekend I was going away to Albany from Friday to Monday - so would be away for almost 4 days. at 6am I do my walk around and final feed to find the pump not working in one of my systems. Luckily I had the spare so did a quick changeover and was on my way. My backup air would probably not last 4 days, so if the pump had failed just after I left, I could have come home to 50 dead silver perch, valued at about $300 based on size. Thats more than the cost of the pump. As a proportion of the overall system cost, an extra $200 for another pump does not seem much to me. However, if I was only ever away for 1-2 days at a time I would be happy to trust just the air pump.

So I now have both pumps plumbed in. Learnt another lesson on why the pump failed. I had my water inlet so that it was below the surface of the FT after 5 mins of pump operation - A clay ball had got into the fish tank and was sucked down into the pump when it switched off, jamming it when it restarted (dry clay balls float!).

So the pump would have been sat there with a locked rotor for a few hours (was pretty warm when I took it out), though after taking out the clay ball, its running again. However its life may have been shortened from running locked rotor like that - but because I'm running two pumps I'm happy to put it back into service. I generally try to stagger my pumps so I have one older one and one newer one together.

Charlie, I think that adds more weight to having 2 pumps - an old and a new one - you can then always have a 'run your pump to fail' maintenance strategy and not feel exposed that you have a 5 year old pump holding up the system.

Absolutely, especially when controlled via flow switch. If efficency is down below your liking and number 2 is in operation then you can buy new and switch them around keeping the strategy in place. Although like mentioned, introducing other components to rely on could be viewed as a complication and failure points. I suppose that is where homework would need to be done to ensure good quality parts are used and that usually comes at a cost. I like to follow KISS principles but as I step up my next system I want to be in control. Ive experience pump failures in the past and it can be a stressful moment, luckily both times I have been home and have had a spare pump laying around, having said this I have always had a spare pump in the FT that creates water movement and doubles as a venturi aerator so that buys me time.

Like you guys have pointed out, it depends on each persons situation.. and in Easts case it seems like he may be away up to 2 weeks at a time... so 2 pumps certainly doesn't seem overkill plus aeration. I would be more worried about the auto fish feeder he has, but hopefully it won't dump a lot of food in all of a sudden. but thats probably not the type of failure his type of feeder would have.