Backyard Aquaponics
A place to discuss aquaponics

James,
there is a big discussion about air pumps here
http://backyardaquaponics.com/forum/vie ... highlight=

Am downloading the magazine as we speak, thanks for the tip.

James, didn't really mean it to be "unkind".... just a bit of a dig....

You have learnt the hard way by making the mistakes.... sometimes it does need to be highlighted though that new systems take time to establish and need to be monitored regularly and stocked lightly....

It's a point I've made in another post as well....

Have got the feeling lately that many have rushed into things without having fully researched the forum and jumped straight to the highest stocking levels (theoretically) possible.

Thankfully you have posted your mistakes, because by doing so hopefully other will see how easy it an be to rush ahead without considering everything that is required

Yes, I hope others can learn by my mistakes!

Now, having read about the sorts of air pumps others are using for their aeration (e.g. 90 watts) it seems to me that the little aquarium air pump we are using is WAY too small. While it looks like it's working (lots of little bubbles) it is probably having negligible impact on DO levels in the 1500 litre tank. We may have to look at one of these more substantial air pumps.

First, I will need to find out what frequency Dad is pumping, as it looks as though that is presently the only significant aeration. I have a horrible feeling he is pumping for 15min, draining for 30min. This is probably insufficient to provide hot-weather aeration.

OH CRAP I've got it. I've just remembered something - CRITICAL information. Dad told me the other day that he'd discovered the pump had stopped pumping (his pump has a low-level shut off). We underestimated the transpiration losses via the plants in this hot weather. What that means is that we had a period of some hours (perhaps even a whole day?) right in the heat wave, where the recirculation simply stopped, so the bulk of our aeration stopped. And the little air pump would have done sweet diddly squat to help.

That's gotta be it, right? Pretty embarassing.

that sounds like your culprit.

Yep - that'll do it. Hopefully no long term damage to the others. Take this as the opportunity to improve the system design and your/your dad's knowledge. Don't stop now that you probably know the answer to this latest issue.

You want to hear something tragic (well, almost tragic)?

Dad left home for the day today, knowing it was going to be a hot day and suspecting that heat had killed his silver perch. But not knowing anything about the DO/temp stuff, he deliberately shut off the water pump so it skipped every second cycle (therefore one 15min pumping cycle per 90 mins).

Fortunately I caught him on the phone just now and told him to put the pump on a continuous flush for a few hours, to oxygenate the water, and relayed all the information I've got from the forum. He said the fish looked fine.

Phew!!!

I've told him to adopt a cycle of pump 15, drain 15 (previously it was pump 15, drain 30). He suggested also having a 1-2 hour continuous pump at the end of the day to boost O2 levels.

We think we might look at a bigger air pump too. He's agreed to do a water quality test as soon as it cools down a bit.

Thanks for all your help, we're gradually getting there. I think we made the mistake of thinking Aquaponics was simple and easy, and simply didn't recognise the complexity of the system and especially the unforgiving nature of it.

Jimmy - out of interest, where did you come into contact with Aquaponics, was it here? Was there anything in particular that lulled you into thinking it was particularly simple - just want to know in case we need to change something.

I personally beleive that Aquaponics can be very simple and can be quite forgiving, provided one follows a set of basic principles, patience is excercised and knowledge is sought. Overcomplication is certainly not somethign we seek in Aquaponics.

Luckily the forum members are very forgiving and helpful. Hope it works from here JW.

Some things aren't as obvious as the might seem....

In hot weather it's the large amount of ambient heat from the growbeds, not the fish tank, that depletes oxygen....

Your pump cycles were perhaps OK for winter and while you were cycling, but in summer you probably do need to turnover your tank volume more often.... ie. more cycles/day....

Both to cool the water returning to the tank, provide sufficient water to the plants to offset transpiration, evaporation and reflective heat and most importantly to provide for the extra oxygenationation required by higher temperatures.

The opposite applies somewhat in winter, when we might like to hold our tank temperatures as long as possible it can be done by either not pumping at night ( I wouldn't recommend doing so without a seperate supplementary air source) and/or spreading the flood cycles further apart.

By spreading the flood cycles further apart the growbeds retain more heat which can be transferred to the flood cycle.

Might also gain some efficiencies by ensuring that there is water returning to your fish tank throughout the drain cycle (with plenty of splash of course). No point draining in 10 minutes and then sitting still for the next 35. Understand what I mean?

I'm with Rupe. Do some homework peoples. Fish in our care, rely on us to keep them alive. If you or the person looking after your fish are not prepared to do the reading, (Google is our friend,) and understand BASIC fish keeping principles, don't get antsy when mild criticism comes ur way. These are living breathing creatures relying on our skill to provide their very basic necessities to keep them alive.

The take home message: do some bloody reading. 'She'll be right,' was obsolete a long time ago.
Fishkeeping comes with a 24/7 responsibility.
Our AP friends in snow wintered parts of USA go to extraordinary lengths to keep their tilapia alive during winter, and grow some expensive greens.
We get a few hot days and people think they can start REDUCING pumping cycles, gmafb. Here in various states, people are desperately trying to keep fish alive during the heat wave/power outages, yet avoidable mistakes are made by others who fail basic fishkeeping principles/understanding.

I regard myself as a fish newbie, but reducing pumping cycles during warmer weather is not only dumb, it is negligent.

End rant.

Good catch on the pump Jim. It's great that just talking with others can stear the solution out. Do you have some pics of your dads system or a link to it?

I've also got a 1500 litre tank, as does Peterall. I questioned on hs page if 100 was too many fish, particularly with his small volume of growbeds. How big are your growbeds? Increasing the amount of grow beds will increase the amount of O2 in the water as will as help with removing wastes etc.

Just did a water test:
pH = 7.6
NH3 (Ammonia) = 0.025 - 0.1 ppm
NO2 (Nitrite) = 0.5 ppm
NO3 (Nitrate) = 30 ppm

Haven't got a thermometer yet.

Growbed is 1.5m diameter, 0.3m deep. Full of living plants but they are not doing very well.

Added a second air pump today, 8L/min = 480L/hr. 2x80cm long airstones (+ 2x 30cm air stones connected to existing small air pump).