Backyard Aquaponics
A place to discuss aquaponics

that new aeration sounds interesting. would love to see some photos once it's finished.

Main and backup air pumps, plus their respective mufflers, currently suspended from the cables that support various plants and vines, beside GB #1. I'll be mounting them under the GB eventually, but for now they aren't really too much of an obstruction.
Heat generated by compressing the air is dissipated by the mufflers, which are warm at the top when running, but at ambient temp at the bottom , where the air exits. The contain a rolled up shade cloth bag to break up the shock waves generated by the piston and diaphragms, which were being broadcast under water very loudly by the air discs. Using small ~4mm hoses will also muffle the shock waves, but also seriously reduce the volume of air delivered, which I don't want. Threaded poly fittings are sealed with O-rings.




Air is delivered to the air discs in the FT via independent 25mm air lines, reducing to 20mm verticals down into the water




Aeration from the main pump, the disc is 30-40cm under the surface, and you can see the smaller backup disc, which is ~10cm deeper. The bottom of the FT is easily visible under 1 metre of water.



With both air pumps running



The backup pump is currently not connected, but I'll put it on a timer until I can get the pressure switch activation set up, and I still need to set up the PV panel and regulator, but the battery will power the air for well over 2 days without a charge.

With a long overdue cooling down of the weather, the water temperature has now dropped significantly, so the ~140 trout can go in as soon as I get a chance, when the water temps in thr 2 systems are close enough for a direct transfer.

There are now 141 trout in the FT The water was 1.3C cooler, 18.6 in the large system and 17.3 in this one.
Water in the large system was pH6.88 vs pH7.50 in this one. I just netted them out of the large one, then we carried them down in the esky and tipped them straight in, 4 trips to do them all.
I'll go easy on the feeding for a bit, and monitor Ammonia, as the bacterial colony has no doubt decreased significantly since last December.

All the trout appear to be well this morning, after last night's transfer. I fed them 150g of pellets, and they were a bit slow to eat them, but all were gone in an hour or so. Ammonia tested as zero a couple of hours after feeding, but I'll be testing daily for a while, and also testing pH, as that will give me an idea of when the bacteria are starting to get back into full swing again.

I love the idea of the mufflers on the pumps. Does it make much of a difference?

Yes, it makes a huge difference. There is an unpleasantly loud buzzing in the tank without them, and it becomes barely audible with the mufflers. They remove the vibrations from the air pipes too, which was contributing to the noise in the FT.

Does it lower the noise of the actual compressor, or just the noise travelling into the FT?

Mainly the noise in the FT, but the 240V compressor was a little quieter too.

This is a very awesome build. I am about to add on a second IBC into my system, and I am seriously considering digging a small crater of my own lol.

Thanks, I hope your soil is softer than mine was at the time


Acidity has increased a bit since adding the trout, now at pH6.8, so the nitrifying bacteria are clearly hard at work
Ammonia is up to 0.25ppm, and I've fed them 300g of pellets today.

I've now got the backup aerator on a timer, to come on for 5 mins every 30 mins, until I get a suitable pressure switch, and have a couple of PV panels and a Prostar PS15 regulator to keep the battery charged.

Well, the ground here in TN where I live, is mostly shale(sp) and red clay. However, a buddy of mine owns a backhoe, so there is that.

I read through the majority of your thread, but I didn't see it mentioned are you using a chiller to cool your FT or just the wax?

I would love to keep trout, but the summer temps here are just to high. There is a trout hatchery right down the road from me, that will practically give me stock. I dont really want to invest in a chiller, so any suggestions would be awesome!

Shale and red-brown clay here, which sets like concrete when it is dry.

I'm not running any heating or cooling on this system, the chiller is on my large system, in which I've kept trout right over summer, in max temps approaching 40C. However, trout are fast growing, the ones Ive just put in here will be ready to harvest from about August-September onwards, until I need to remove them all in Nov-Dec when the water becomes too warm. I was initially thinking of using wax to store heat for fish that require warmer temps, but the trout go so well I dont plan to grow anything else now.

You probably should be able to pick up some 100mm fingerlings in say October, and harvest decent sized fish in April-May, depending on just how warm your fall and spring air temps are. What's your nearest town?

The nearest town to me is Knoxville, TN in the USA. Im right smack in the south east, where our springs run upwards of 80F and summer hits 100+ with 99% humidity on a pretty regular basis. Not your ideal trout weather. Now dont get me wrong, there are loads of trout here, we have a bounty of clear cold mountain rivers and streams that are slap full of them. However, I have never kept them in a container of any sort.

I've just had a look at your weather averages, generally cooler than here, with summer about the same and diurnal range a bit less (but a lot more rain), so you should be able to grow trout during the Oct to April-May period I suggested earlier with careful use of insulation and shading. 99% relative humidity wont worry the trout too much