Living in NYC you never expect the power to go out. It happened only a few times i since I was born. Then there was a storm serge which hit the East Village power grid with multiple explosions. Hurricane Sandy silenced my aquaponic system with no pump, no aeration and no backup power. I really wasn't very worried about my fish because I only have two 5 inch goldfish in a 26 gallon tank supplying nutrients to my 4 cubic feet of grow bed. So not a huge loss if they didn't make it.
Needless to say I had to get out of there with no heat and no power. My goldfish were on there own. I already knew that fish could go a long time without food so I wasn't worried about that. I knew if they weren't eating it would be a while before the water chemistry was an issue. I was only worried about O2 and when I came back in 2 days to check on the system they were hanging out at the bottom of the tank just chilling out. I pumped my grow bed manually to make sure the plants had water and didn't come back again until the power returned.
I had worried about this scenario but when you have a 1/2 pound of fish in 26 gallons of water there is enough O2 exchange on the surface to support them. We all hear about stocking ratios of 1 pound of fish per 10 gallons of water and I suggest that even that is not needed. If you are looking for a no worry situation when it comes to power stock a lower density of 1 / 30.
Glad to hear things were ok, Jonathan!
Glad to see you and your system made it through the storm intact.
I can only imagine what a challenge that has been for everyone. My system would have crashed - I feel there is a generator in my not so distant future.
Yeah if I was in full on production mode i could see a generator as a necessity. It gets me thinking that people should do a stress test on their system to see how long they have until parameters go out of wack. O2 being the most critical. And thanks for the good wishes.
That leads me to another question; what are people using for DO meters?
Everything I have found is beyond my budget - usually beyond the value of my whole system so far.
Is there a cheapo way to measure DO?
Hey Jonathan, sorry to hear about the hassle and troubles you and others faced due to the storm. Glad that everything's alright...AP and otherwise.
Stress testing and back up power sure are a good idea, I'm kinda pricing out some stuff now, but probably wont pull the trigger until springtime.
Bart, most folks are probably using their fish for DO meters :) Gulping at the surface can be a sign of O2 issues (O2 issues may go beyond just having enough air in the water though...the beginning signs of some metal toxicities also include gulping air at the surface due to the hypoxia such toxicities bring on...anyways)...As you've notice digital DO meters are expensive. Especially one of decent quality. There are reagent type kits, but they're not cheap either...and are quite complicated for most people to use. Probably not worth it for a home/backyard scenario.
Thanks for the feeback Vald - I was thinking that might be the direction the answer would take but thought it worth asking.
I've been taking the approach of erroring on the safe side and just biggie sizing the air pumps but it'd be nice to know what impact different changes I make have on the system and how close to the line things are.
I got a little excited after seeing what they use at the Guelph / Alma research station last week - it's amazing what a couple million $ of government funding will get you.
As for backup systems, I was at Lowes the other day, they had a backup generator, I think 6000W for $1800 runs on Natural Gas and apparently fires up automatically when the power goes out - not sure what the cost to install and properly wire it would be but I would guess it could easily double that.
It would be sweet, but I can't really justify it on 70 fish.