Backyard Aquaponics
A place to discuss aquaponics

Bad news story about my local trout farm:
http://www.abc.net.au/news/2014-12-30/d ... ng/5992632


I assume this relates to the very hot weather we had in November, but it has only made the news over a month later. We've had above average rain in December, so I imagine conditions have improved somewhat.

I'll have to get in touch with Russell to check if they can still supply my trout in a couple of months.

Wow... it felt bad when one of my fishies jump over the tank and die, i cant imagine that!

happens all the time, 99.9% of farms wont tell anyone unless they are seeking some sympathy help from government or charity.

with todays relatively low prices of oxygen monitoring he could have afforded a full oxygen monitoring system with the $40k projected loss plus some change, just poor business not to have it and alot of farms still dont.

Bottom line is that in some ways farming of any kind is a gamble. 40K is a lot of money to invest when you may or may not need the equipment. A lot of companies make choices like this and it's not necessarily a bad business decision until something like this happens. On the other hand he may already have the equipment

WOW that sucks 10,000 trout. Guess this isn't going to hit the trout appreciation thread.

He still has plenty left, although at a smaller size than usual for this time of year, so my 150 on order are still available... so I have to get my 2nd system built ASAP.

DO problems strike all the time at this time of year, we currently get at least 1 alarm a night where we have to go turn up oxy cones or alter flows etc. I worked at a farm that didnt have it and every year without fail we lost enough fish to pay for a oxy system 3x over.

Been working at a farm with it for 2 years now and have not seen a single fish lost due to low DO. it speaks for itself.

to me if you could buy something that would pay for itself in less than a year, its bad business not to have it.

..
What actually happens at higher temperatures.. oxygen does not dissolve as well... but does this mean there is no way other than cooling..

Dumb question, but prompted by the thought that whilst DO is measurable at a price, if you simply can't get any more O2 into the water then who cares... let them go to sleep...

But if it is possible to fix the problem, then is it not a simple case of measuring water temp and reacting ...B4 the critical temperature ..

Ie... we know there will be a DO problem, so just do it.. blow more air at any cost...

Am I missing something..?
..
.

water temp makes oxygen less soluble, see this: http://www.dnr.mo.gov/env/esp/wqm/DOSaturationTable.htm

It also speeds up the fishes need for oxygen through more swimming activity, they also feed better in warmer temps and need more feed to keep them from nipping each other.

You also get alot more algae and weed growth in the water so during the day the DO is great and around 6-7pm ponds start crashing.

There are alot of factors that contribute, the only fool proof way is to measure the oxygen in the tank or outlet of the pond and its very effective, we can watch the graphs for the ponds and know when something is heading in a bad direction and react before it hits alarm point. We can also plan our feeding activities based off it.

i took a picture at work the other day to show what i meant:

can clearly see daytime and nightime in these DO graphs for some ponds at work. Pond 6c in teal colour has no fish and very little water flow going into it and has alot of algae, you can see of a night it drops to just about 0 and during the day is up around normal ponds. The sharp up and downs you can see on all ponds during the day is clouds cover and the sun peaking through every now and then, thats why its a much straighter line at night(but on a downwards slope). Hope that helps!

helps alot thanks

damn that sucks, poor guys.

Here's a different way to lose some fish. 11,000 chinook salmon smolt

https://inf0rmati0n360.wordpress.com/2015/01/02/oregon-us-fish-hatchery-truck-crash-investigated-as-dui/