Backyard Aquaponics
A place to discuss aquaponics

Consider yourself backed up.

Sorry guys, I agree with Stuart on this and he has given more examples than I would have had the patience to give.

Note

Remind myself not put my sump pump in a 10m deep sump. Remind myself not to inject hp air into the bottom of a 1m deep FT unless I am using it for good purposes.
Although I would really like an approximately 53m high waterfall in my back garden, unless I win lotto this is not going to happen.

I agree also with Stuart. But diving disease comes not from fish going deeper to compensate for nitrogen, but from the fact it generally occurs with divers.

The OP's original question was if he would get more DO by hanging his air stones on the bottom of the tank, opposite to having them hanging at 30cm deep.

Answer would be YES, I think.

The rate at which gasses dissolve in water increases with the pressure of the surrounding WATER. Given the same amount of air flow and the capability of the air pump to overcome the pressure at the bottom of his tank (and maintain the same air flow) more air will be dissolved at an ambient pressure of 1.1 bar than with an ambient pressure of 1.03 bar.

Since he's not planning to inject air at a depth of 10 meter…...

The example I originally gave was 1.5m which is still likely to result in very sick fish at best.

oh im not disagreeing with stuart, i know nothing about it, im just trying to prod him to get the most comprehensive answers we can and so i can understand what he is saying


Stuart, i have a 6kl water tank i am running as a bio filter, its 2m tall and dug almost half way into the ground. i have open air lines running to the bottom of it ( for water movement) which i was planning on maybe running at all times ( but atleast when i turn my system off at night).

Do you think this willl cause a problem?
Is this still a problem when the system is in hiatus over night?

The water level isnt quite 2m deep, but its sti more than the 1.3m that my FT's are.

Also, i have a charlie style growbed that i will be using as a trout run - 40cm deep, my 2 other tanks are 1.3m deep, will the air injecton in my deep tanks cause this effect in my trout run?

(all these tanks are linked through sump and bio filter)

For the later I'd say that is likely to be a real problem. For the biofilter it would depend on whether the extra nitrogen would have time to diffuse out of the system water before it got delivered back to the FT.

it runs from biofilter to either sump or trout run (then to sump), from sump to nft then back to FTs, then RFF, then biofilter.

I know, im working out a way to filter the trout solids. .
its not the greatest setup, ive had to squeeze alot of filters/beds into a very small drop.

The air consists of a number of gasses, these exert pressure. The sum of the pressure could be described as 1.

Water also contains dissolved gasses these change because of a number of reasons but our main problem is that O2 is used by many organisms and CO2 is excreted, this alters the gas balance in water. The imbalance will for the most part will correct itself at an air water interface, in other words will try to return to the air gas pressures and again sum 1.
If the pressure of the gasses in water exceeds 1 it is supersaturated ie the total gas pressure is exceeding the total air gas pressure.
What Stuart is trying to tell you is that deliberately supersaturating water by injecting air at a pressure much greater than 1 is not a very bright idea.

Well thats what I think he's trying to tell you.

Very well, I learned something today, thanks for the info!

But....... For any people building their little backyard system who are scratching their heads, thinking perhaps they may do something wrong with their aeration?

Don't worry about it....

As long as your aeration is in your FT.

lol... And the title was.......?

Plus I don't know anyone that has sumps as deep as your suggesting in their back yards.. So for the backyarder, I'm just saying, don't get put off and confused by some of these discussions, chances are, it won't relate.

I just see a fair few people that pick up little bits of info and relate it to their situations and get worried when it doesn't necessarily relate to them.

Hey I answered the original question in my second post.

I dont think it was the second post that EB was referring to.

But luckily, if any of the 4 or 5 of the commercial systems in the world were looking for information on how to or not how to aerate their fish tanks.... they would be very grateful for this thread hehe

This information may be of more direct relevance to small scale AP than it first appears.

I use ground (bore) water to top up my big concrete tank and I'm sure I'm not alone in that respect. Once last year when I accidentally left the valve open overnight the tank overflowed and a large percentage of the original water was replaced. I also lost some trout at the same time - they were floating when I discovered my valve error. At the time I assumed their deaths were due to a lack of dissolved O2 in the incoming water, since it had come from 30m underground. Now I am wondering if the bore water was, in fact, supersaturated and that was the reason for the fish deaths. Any ideas?

If this is a situation that could cause diving disease in fish then it is one of which new players need to be aware.