Backyard Aquaponics
A place to discuss aquaponics

Hello everyone. I've been snooping through this forum for a few months now, soaking up information while building my greenhouse and planning my aquaponics system. I first heard on aquaponics through a coworker who is building a system, and started reading up on the subject. Back when I lived with my parents I was an avid gardener and tinkered with aquariums, but since I've been married and living on my own property I haven't had time to get back into that until now. Combing both gardening and fishkeeping into one hobby seems perfect

However, I am completely off grid, and must run everything from my solar/wind system. I would like to have as large a system as possible using the least amount of power. The system I am planning is a pond of roughly 1,200 gallons (4,542 liters) dug into the floor of my greenhouse, pumping water up into growbeds made of blue barrels and IBC totes.

The most energy-efficient pump I could find for this size of FT is the Laguna MaxFlo 1350: http://www.123ponds.com/pt8240.html?gcl ... QgoddgoA7w

I could run this constantly for a total of roughly 1750 watts a day (factoring in inverter 'waste'.) But half of this would be at night, cycling my batteries.

Or I could run a small pump at night for aeration, and a larger pump during the day (when my solar panels could easily keep up with the extra draw) through the GBs for filtration. Would that be safe for the fish? Would 12 hours of light filtration (say, about 300gph) followed by heavy filtration (2-3,000gph) be as effective as a constand 1,300gph? It would still be cycling the full volume of the pond about 24 times in 24 hours.

Does anyone have any tips or tricks for saving power and still keeping a pond full of fish happy?

During winter I turn my pumps off at night to save the water temp. I just have a small air pump running through the night and my fish are doing fine.


But it will be dependent on your fish stocking densities.

The low flow/high flow could work as long as your stocking density and feeding rate are appropriate.

There are some really good threads around on low energy systems I'd do some more searching. Since constant flow constant flooded systems seem to do ok for a number of people I'd check out those designs because if you don't have to flood and drain you can really lower your power requirements.

I'm completely off-grid and run my system with no problem, currently with 3.5kW of solar, a small 200W WTG that produces nothing most of the time as it isn't very windy here, and 21kWh of LiFePO4 battery storage. I haven't had to run a generator at all since I've had the AP system operating (end of April). My system has about 6000litres of water total, with a 4500l FT, operating @ ~4000l, and 2000l sump. I run a 65W air pump full time, as well as a 35W air pump that comes on with the 260W water pump. Currently that is on for 30-50mins per hour overnight and 15-20mins per hour during the day. In winter I cut the night time run times back a lot, and increase the day run time, mostly for temperature regulation. In hot weather I also run a large chest freezer full time devoted to making ice, plus some ice making in a smaller chest freezer and the fridge, in order to keep the water temperature down for the trout. I'll be using a fair bit of it over the next few days of 33-35C forecast temperatures.
My FT and ST are buried, pics and details in my system thread.

Having spent quite a lot of time in Az, I reckon you get a bit more sun than I do, so, depending on your household use, running entirely from solar wont be a problem.

You do have some great thoughts in your mind..Ideal is to use solar panels and small wind mill for gaining green energy.

I forced my powerhead into the inlet [to] my slo the other day, and it doubled the flow into my growbeds.

My pump is a 60 watt BYAP pump (ie it's of decent quality) , and my powerhead is 5 or 7 or 13 watts.

Sorry for being so vague, but that's just the way it is.

But a ducted propeller moves a stack of water!

I second the low flow/high flow setup.

You could also adjust your feeding routines accordingly so the fish get their main meal in the morning and another just after midday but none towards the end of the day to reduce the need for filtration at night.

If it was a choice between running an air pump or pumping to the growbeds at night, I would go for the air pump as your fish will need oxygen before they need biofiltration at night. Obviously you get a bit of both with pumping to the growbeds with a small pump, but I still think a couple of low wattage air pumps will add more oxygen to the water.

for example, I have a 980 litre per hour 12 volt pump which can pump approx 600 litres per hour at 700mm head drawing 5 watts, or I can run two small duel outlet air pumps (4 airstones) for the same wattage

You have a good amount of water to work with. Just stock conservatively and build up as you learn the limits of your system and you'll be right.

Also remember that oxygen demand will be greater in summer than in winter.

I tend to avoid expensive batteries and associated charge controllers all together and just pump during the day with my pumps wired direct to the panels. I oversize my panels so there is way more spare wattage than I need (panels are cheap compared to batteries), which enables my pumps to still run in light overcast and rainy conditions.

If I get a string of heavy overcast days (very rare where I live), I just stop feeding the fish temporarily to reduce biofiltration demand.

Conversely, on very sunny days I feed heavily as possible, creating a reserve of nutrients in the water.

I love running aquaponics off solar. The sound of all that water running with happy fish all from the suns free rays is very satisfying

I presume from this Jono.. that you hope to create an excess of nitrates??

But have you actually charted whether or not this actually occurs...

I'd suspect that the plants would just use what's available... resulting in effectively no real "reserve".. or "nutrient bank" at all....

No haven't charted it yet Rupe, but I probably should

It would only a very short term reserve eg say I get say a day or two of heavy overcast conditions.. I doubt the growbeds would run out of nutrients over this timeframe? Perhaps growth would slow a little at worst

Would be interesting to log the Nitrate readings and see how it's fairing nonetheless

I wouldn't have been able to do this when I was living in Sydney as the weather there is seemingly regularly overcast etc

I think I could pull the fish out of my system for a few weeks and still be producing nitrates just from the reserves of silt that are trapped in the beds.

Over winter they run pretty clean, but over summer they silt up a bit.

My nitrate readings are almost always just above zero.

Ralph,

If you took some flour, some water, and some yeast, and mixed it all up in a bowel, what would you get?

1. Banned

2. Solids

3. Bread

?

What about getting some capacitors into the system? I did see some remarkable applications of them recently on youtube. Replacing batteries!

Thanks for all the ideas, everyone. It looks like using the water pump during the day and using an air pump constantly will keep me within my energy limits and keep the fish happy and healthy. I'll do more research into the constant flood growbeds and capacitors to see if they will work for me.

I'll post pics and updates when I get into the building phase of things