Backyard Aquaponics
A place to discuss aquaponics

Hello All!

I have had a temperature issue with my fish tanks that cooked my yabbies on a hot day a week or two back. They wernt quite ready for the table, but they were all dead. Goldfish survived alright, but i have had redfin in the tank that all die and the only thing i can come up with is the temperature variation for day to night. the tanks are in a greenhouse so it does get hot during the day and my temperature monitoring device (my hand) says the water goes from warm to bloody cold.

My idea was to dig some trenches outside about 30mm (1ft) deep and lay 3/4inch poly pipe in them and run the water through them when returning to the fish tank. I cant get the fish tanks out of the greenhouse now it has plastic, but i could use some others that i have. I suspect however that the with the grow beds in the greenhouse anyway this would not make much of a difference.

I was wondering if anyone has tried something like this or has any great ideas that can help?

I do have some photos on my system page "Mr Fishos Meredith beginings" but not sure how to like to it.

Hi Mr Fisho

Shade cloth over the fish tank and grow beds for hot days should help. Not sure how hot it gets down your way but we had a spell of 40 degree days recently. I have got 50% shade cloth inside my green house that is clipped to wires and can be pulled over the top of the whole system and that kept the temps in the tank down to 29.

Hi fisho dont bother with the trenches i dug trenches 2 meter deep 30 meter long with 1 1/2 dia hose and it made little difference the only to get it more stable is get a larger water volume also in my glass house i have removed glass from both ends and a fine water spray helps cool things down Also an aquariam thermometer is about 5 bucks [a good investment ] also do you have extra air 90 % of the problems i see are people trying to run without extra air

More water. Will have to start checking mine.

The heat will definitely do that to the Redfin Perch.

I have seen literally hundreds of fingerling die this way in the waters of Blowering & Burrunjuck Dams. The NPWS guy said to me that the HEAT is the problem as it draws most, if not all, of the waters' oxygen thus effectively suffocating the fish

The immediate fix would be shade cloth [min 50%] on both the GBs and FTs.

A trick use in aquariums may help in extreme emergencies, and that is ICE, lots & lots of ice.

This will no doubt affect your tanks parrameters, but it will also help to save your livestock

HTH

Adding water adds thermal mass - if you can couple the water effectivley to a large thermal mass, e.g. a concrete slab under your house then you might be able to increase your thermal mass without increasing your water storage. Of course more water is always better for obvious reasons.

Just a newbie here, but I was wondering if adding air bubblers to the tank help with oxygen problem on hotter days?

absolutely, the warmer the water/air the more aeration your tank will need.

Physico-chemical characteristic of water - the colder the water the more oxygen holding capacity it has.

Cold water = higher DO
Warm water = lower DO

yeah they do, it's been done heaps, and is seriously recommended with trout.
F&F has recently concluded an experiment that shows bubbling air through a tank for aeration, provides a significant decrease in temperature. - 2 degrees or something.

So for trout this is a big plus.
A) it removes the lack of oxygen at higher temps
B) it reduces the temp, thereby reducing the need for said oxygen.

The idea of trying to get some cooling effect from the ground is not a bad one but there are things to keep in mind.

The idea is sound, it is often called geo-exchange and can be used with heat pumps to do HVAC for homes. However, horizontal ground loops though they might be the easiest for the do it yourself types, are generally the least efficient. Sandy soils and dry soils are very inefficient for this as well.

Unfortunately, to get much benefit, you would need to go much deeper than 1 foot and probably still need a compressor unit to make the differential useful for cooling.

I have found that my system benefits a fair bit by having an in ground tank. In summer my system temps stay a bit cooler and in winter my system temps stay a touch warmer.

To cool things off much, I agree that shade cloth over the entire system and even stronger shade over the fish tanks. I have heavy fabric hanging several feet above my fish tanks that shade them very well. If in a greenhouse, definitely open it up as much as possible for the warm season. I live in a hot climate and will completely remove the plastic from over most of my system and the large section will have the sides and ends removed or rolled all the way up for the warm season which starts here shortly.

I do run a small aquarium air pump 24/7 and continuous water splashing back into the tanks, but i could always do more i guess. I'll give the shade cloth a try to see if it helps. Unfortunately the plastic on my greenhouse cannot be temporarily removed, but i do have a roof vent that works fairly well.

Do you think a larger tank outside in shade would make a difference with the grow beds still in the greenhouse? How big a tank would you think i need? I dont have any real space restrictions. i did consider the idea of getting a raised garden bed, digging a hole in the centre, and using a pond liner could give me 3-4000ltr tank half in the ground at a reasonable cost. Perhaps i need to revisit this idea:)

have you considered burying a tank? Ground temperatures are much more stable.

I'd imagine having your air pump inside the house, pumping airconditioned air at 24degrees, into your bubblers/FT rather than hot air from outside at 40degrees, would make a bit of a difference. Every little bit helps.
Wavey.

Does seem like a plan.
Mine are half buried, and going to be given they're own shed soon, so hopefully that will solve some problems.

Only thing is, for servicing, I have 300mm gap bw tanks and earth. so not too much thermal load offering

Or from under your house if you get sick of the noise.