Backyard Aquaponics
A place to discuss aquaponics

Your right Steve, I think that this subject deserves it's own topic as it's very important...

One problem with many of the UPS's is that they aren't very ruggedized for outdoor use. I did once come across some second hand UPS's that where specifically made for outdoor use and they had damn big batteries internally mounted in a nice strong box that was weatherproof...

The optimum cheap and easy way of backing up your system is to have the air pump on a backup power supply, but not having the pumps working can also bring about other problems. In a large flood and drain system like mine when the power goes out and the pumps stop working, the water just drains out of the system, overflowing the drain tank. Then when the power comes back on again theres not enough water in the system to start the pumping cycles again.. This will still keep the fish alive for a fair while, so long as the air pump is going, but you'll want to get the water moving again fairly quickly..

In the new system I'm designing at the moment it could be even worse.. Water is going to drain back to the fish tank from the grow beds under gravity, this is great. If the power goes off, all water in the system will drain into the fish tank, it will be full and the fish will be happy, so long as theres a bubbler left going.

As the system all drains back into the fish tank, there will be excess water from the grow beds and this will overflow. Then when the power goes back on and the water starts pumping, it will take a fair bit of water to fill up the grow beds and get the pumping system all going again and this will lower the level in the fish tank, possibly by up to about 40%.... Very crowded fish...

Might be time to do some calculations of UPS size and pump size.......

I did find a UPS here http://cgi.ebay.com.au/UPS-1000VA-NO-RESERVE_W0QQitemZ6868585077QQcategoryZ111430QQrdZ1QQcmdZViewItem that looks like theres an external battery lead maybe....?????

And only $20, though I think the postage costs would kill me over in Perth.

Yep, i saw that one to joel watching it actually!

i like the external battery lead too!

Is it worth you moving some of the posts from the other topic to this one?

There are many ways to have redundancy in our systems, i could wack together a little 12circuit with a relay power supply and a few components that would give your 12V redundancy for a 12V air pump, but considering the price you can pick up a UPS from ebay and the fact that they are basically Plug and Play i think makes them the better choice. Couldn't be too hard to keep one under cover enough to keep it alive.

Hi Guys,
The UPS idea is ok, but I really can't see why one can't just have the 12 volt water pumps and air bubbler running from 12 volt battery bank, (actually 24 volt is better - less amps to do the same job) The battery bank can then have a 240 volt powered trickle charger attached, or/and a solar panel or two to keep the batteries up. With a decent battery bank the whole thing would continue to run for many many hours after the power went off (during the night) and would continue to run without a problem during the day on the solar panel/s.

If you look at the specs of the UPS units on eBay that the links on the Forum led to, they do not have the grunt to run anything except a very modest bubbler. These units would only keep a bubbler going for an hour or two at best.

In any case, you don't really need a bubbler if your 12 or 24 volt pumps just keep doing their job.

For me anyway, I will be going that way.... After many thousands of miles at sea on sailing vessels, I have found it is not to difficult to have a 12 or 24 volt system running the pumps with a very very high degree of reliability, yes it will cost several hundred dollars for a decent battery bank, a hundred or so dollars for a good top line 240 volt battery charger, and after a few months, I will be happy to invest in some decent solar panels. That is why I wish to go the 12/24 volt direction, because I believe that in the long run it is more reliable......anyway it fits better into the whole concept of self sustainability. (once you have solar and wind turbine power to keep the batteries up.)

I am interested in having a really good reliable system that can produce the goods.... Imagine the loss of your fish and vegies when they are just at their peak because the system was just not up to scratch..... It woild break your heart....

It is not going to be too hard to run all of my house lighting off a decent battery bank with solar panels as well. The really interesting development of LED lighting makes lighting your home from 12/24 volts very very dooable these days. New and better lighting coming onto the market almost every day.. LED's burn less than a tenth of the current of an equivelent fluroscent tube of the same light output.
Anyway LED lighting has little to do with Aquaponics, but it makes the 12/24 volt option more interesting to me. Murray

Murray,

a few points

I see your point with the 12V pumps and the charger, much simpler however do you know the current draw of your pumps?

they are usually quite high, and unless your charger is rated at LEAST at that current CONTINUOUS then the net effect is that the batteries will run down even when the power is on and the should be "charging".

EG: if the pumps draw say 15Amps (the Rule GP Pump you posted earlier) then unless the charger or power supply can provide MORE than 15amps continuously then there is more coming out than in

Secondly i think that a UPS will last MUCH longer that 1 - 2 hrs on an air pump. One of those i linked to (small unit) had a 9Amp Hour battery. Multiply that by 12Volts to give you 108 Watt/hours now if you're drawing 10 W that comes to 10.8 hours.

I know that there are losses between the 12 - 240 V conversion and also in the non linearity of the current VS amp/hour curve, but at even a 50% loss ( ) that would give you just over 5 hours running time supplying 2 seperate dual outlet aquarium air pumps taking 5W each.

I think some one will have to just try it. much more reliable than theoretical calcs.

steve

Hi Steve, It is obvious that both ideas have merit... I think that DC in general is the way to go personally. I do not plan to have pumps that run continuously. The system Joel outlines in his book is what I am working toward, ( but with DC instead of AC Pumps), with two pumps both starting and stopping as needed. I don't know as yet the size/capacity (and therefore the current draw) of the pump/s finally needed..... but it won't take long to figure it out once I have a fish tank and grow beds set up... I can then do some serious testing of water flows etc before planting those good old tomatoes, and laying out on those wonderful Silver Perch you have been talking about...

It is not too difficult to buy a battery charger that will pump out 15 amps when needed. But I am anticipating that the total load will be much less than 15 amps, say, just to pick a figure for the sake of discussion, as the load iwill be intermittent... ...Murray

Very true, I assumed continuous flow for some reason

I have no problem with DC at all It would certainly make redundancy easier .

This technical stuff is killing my brain!

I can understand the importance of having something like an UPS to handle any 'downtime' with the pump....using a bubbler. All the techno stuff is confusing to someone like me whose career didn't have much to do with watts and amps thingy's.

However......On the subject of which is a good bubbler I have a question or two:

1. I now have two fish tanks, both which will hold approx 3800lt of water. Now I understand that the answer I'm after will depend on the size/number of fish in the tank but....what is a good size bubbler?

The following link has a few for sale http://www.equarium.com.au/store/category.asp?catid=10

Just what size tank is a bubbler that can deliver 1300cc of air per minute meant for? Is it suitable for mine? Or....what volume of air would you reccomend?

Hmmm guess at the moment I only have the one question.

Corny,

If the UPS techi stuff is killing your brain, then i'll apologise in advance for the link i'm about to post below, becasue its doing MY head in Nah, just got to read it a few more times

The Big question i need to ask, is how many fish will you be stocking?

That is the only variable that really matters.

I lie tank size and hence stocking density does ofcourse, but only because a larger tank USUALLY has a larger surface area in contact with the air.

I'm not sure how much you know about fish and aquariums, but i'll list some points that may make thigs a lot clearer.

OK, here we go

1) At the surface of any water body carbon dioxide released by the fish is exchanged for oxygen from the atmosphere. this goes on continuously and to a point where there is some equilibrium in the water between the CO2 and O2

2) This exchage ony occurs naturally at the waters surface, and as very still water can form stratas (layers) the top few centimeters can be well oxygenated while the bottom of a tank can be hypoxic.

3) surface agitation (by a paddle wheel) can be as effective as an airstone, but usually noisier and an airstone is a simple for everyone solution (imagine a paddle wheel on a home aquarium )
Some websites says that the only reason an airstone increases oxygenation is because of the water movement that makes at the surface. I believe this to be INCORRECT, as each individual bubble can perform the same gas exchange while in contact with the water. The surface agitation when the bubble bursts only ADDS to the O2 exchange.

So you can see that the more fish you have - the more O2 requirement you will have. And the smaller your tank is, the less natural O2 exchange.

Corny, sorry if your eyes are watering at this stage

When you read the link below you will realise that the total O2 requirement is a factor of 1) the number of fish 2) the amount that you feed and 3) the amount of bacteria. Fortunatly 2) and 3) are a direct relationship to how many fish you plan to have.......

so give me that and i'll give you the exact CC/per min.

I hear ya saying "Gee, U could have just said that straight up "

True, but i feel better when i've explained something. Just think, buy the time you're done you'll be a "techi" too

Actually, where i've said "number of fish" it should technically be "weight of fish"

The only reason that i lost 22 Silver perch when the power went out is because i had them in a 180 litre aquarium!!! If i'd had them in a 1000 Litre tank they probably would have been ok. Yet if i had 150perch in the 1000 Litre tank then i might have had the same problem.

Here is that link

http://www.bioconlabs.com/oxy.html

My flood and drain system has the return water being pumped back into the fish tank every 6 minutes or so, this return water is well oxygenated, and gets well mixed into the fish tank water. I can have stocking densities of 50kg in the 2000l tank without any extra aeration without a problem.

I guess it will all depend on your ultimate system design as to whether an air pump becomes essential. I do use an air pump at the moment, however I haven't always.

One point I will make about the air pumps is that you get what you pay for, I've been through a few cheapies now and my latest buy seems a lot better than previous ones. My latest pump cost $95, when there where much bigger pumps for much less.. It's a 'rena 301', made in France, it only consumes 5W and it pumps 200 litres of air when submerged 1 metre below the water surface, this is big enough to suppliment for my 2000 litre fish tank..

That one you mentioned there Corny would be quite beg enough for what you want so long as you don't push your stocking densities too hard..

Yep, I agree with you there Steve, number 3) it's definately about the individual bubbles making more surface area of the water able to exchange more O2. Half the reason why we use air stones that create many small bubbles, this creates more surface area compared with larger bubbles..

As you said joel, your water returns freshly oxygenated.

Air pumps would really be of use during a power out.

Or if you're managing crazy stocking densities

Corny, don't get too hung up on the UPS and Air bubbler at this stage.

go light with your fish stocking and you'll be safe even with a power outage.

What do you think joel? 25 silver perch in a 3000L tank should survive an outage of a few hours with out too much stress?

I've got about 130 in my 2000 litre tank.....

Last year when I had my Barra in the same tank, I had a pump blow so had to go and grab another. I had about 80-90 barra at probably 150g each that were left for 2 hours without any aeration. When I got back a couple had jumped out and the rest were looking VERY unhappy, but perked up when given some oxygen...

ok...thanks for that. It all makes sense without me having to dwelve too far into the technical side of life.

I would look at a stocking level of approx 50 - 60 fish.

The bubblers I linked to aren't the ones I'd buy...will definately spend the money for something that's going to last.

I was also thinking of making a bracket type thing to grow duckweed (covering at least half the water surface)....this I assume would stop, or disrupt, the oxygen transfer...but then what levels, if any, would the duckweed take oxygen from the water?

If I can do this with both tanks I'd have 5sqm of duckweed growing space.

I like this idea as to start my grow beds probably won't be large enough to keep up with the fish (when they're bigger).

Thoughts?

Ok corny,

Like i said earlier the airation is only a problem when the power goes out and you dont have the return water sloshing around adding O2.

The duckweed cover should only come into it when the pumps are on the off cycle or the power fails.

Lets say 60 fish at 750 grams each (when they're all grown up ) i've worked this out to a total oxygen demand of 126grams per day.

If you don't mind spending about $135 on a air pump then i can highly reccomend the one i have, it draws 10 W and puts out 30L per minute (30,000cc) and i've worked this out to be an oxygen potential of 162grams per day.

i think its made by electromagnetic air pumps, model number MAP30

has been running 24/7 for about 4 years, no problems yet

The duckweed shouldn't actually USE dissolved oxygen, as the leaves are floating, and in contact with the air. but any way, there is 36grams per day "spare".

Keep in mind this is when the fish are at max size

having said all that when you first stock your fish you could probably get away with the $17 one that you linked to until they get bigger

One REALLY important thing with air pumps is NOT to restrict the output directly via those little valves you can get. ITs the best way to kill the diapragm inside them.

If you want to reduce airflow you can use one of those valves as a BYPASS to bleed air BACK TO THE ATMOSPHERE, this way there is no extra backpressure on the internal rubber diaphragm.

Was tring to work out a way to have the airpump only kick in when the power goes down (the UPS will run it all the time) but then i thought "what if your main water pump burns out (like joels did). Better to just run it 24/7 then you're 100% covered. Also in Joels book he mentions trying to keep the "off" periods of the pump to daylight hours as algae O2 demand peaks during the dark. running the AIR pump 24/7 would negate this requirement

Hope this helps

Steve

Joel, just re-read your last post about your air pump.

are you sure its 200L and not 20L

actually just looked up the specs on rena 301 its in L/HOUR

i was quoting litres per MINUTE

Freaked out for a sec, 200L/min is like the 1.1KW barrel fans i use for commercial aircons i was thinking "where can i pick one of those babies up for $95"

that would put yours at about 3.3 L/min submerged 1M

Guys (and girls )

Very important thing to remember when picking any type of pump is that they quote max flow at zero "head". for liquid pumps this mean pumping horizontal, the flow is reduced considerably when pumping "up" 1 metre.

Same goes for air pumps the L/min is quoted "unsubmerged"

Bigger is always better (in this case )

You can get 'power fail relays' these are useful for turning on appliances that have alternate power supplies, when the normal power supply fails.. But for the cost of running the air pump 24/7 it's so much easier to leave it running....