Filters and Oxygen Starvation

[Jchillin]

Two questions in regard to the canisters and O2 saturation:

1. If your outflow is submerged, and you have a lightly..non-CO2 injected tank...and no bubble wand - How much O2 is available?

2. Wouldn't this be considered a "closed system" (non-aerated)?

 

[greenmaji]

Jchillin..It would depend on the surface area of the water in your tank, gas exchange will happen even without aggitation, and the system would not be completely closed unless the lid on the tank was sealed on and never opened.. and as far as O2 is saturation is concerned Im sure the water is not saturated but a measurement of how much O2 is most likely more information than is needed.. you just need to know that your getting enough for the filter and inhabitants.. as you said before if you not getting enough you will go through mini-cycles

 

[caudelfin]

But the main question was: will forcing air from an air pump up the intake of a canister cause the filter to stop functioning?

Assuming that the canister filter has its pump located at the top of the canister, and is operating in a 'suction' mode, then yes, injecting air up the pump intake hose is probably going to lead to pump cavitation and/or airlocking (i.e. loss of 'prime'). As to doing any actual physical harm to the pump or filter, probably not.

One method of getting additional O2 is the addition of a bubble wand. While most folks think of them only as decorative, they do supply surface agitation

true, I run a bubble wand for this reason, and they also effectively increase the air to water contact area of a given size tank by adding the net surface area of all of the air bubbles to the tank's top surface area.

Caudelfin, my own easy answer is to run two 'smaller' filters -- one of the canister/modular style for the best mechanical and chemical filtration, and another HOB style filter with a bio-wheel so that the bacteria 'conversion' reaction has access to all of the atmospheric O22 it needs.

Thanks,
Yes I had an idea that this would cause pump cavitation, but the canister that I am looking at, the FilStar XP3 states that air bubbles present no problem to it. However, I do not think I will force the issue. Sure it is understood that most aquariums have plenty of O2. But if you are as heavily overstocked as my aquarium sometimes gets, it is indeed possible to have the fish at the top gasping for O2 just before daylight when the plant oxygen intake is at its greatest. As soon as the daylight starts streaming through the window the plants start producing O2 again and when you turn on the vho flourescents then everything goes back to normal. Bubbles are not a good idea if you do have a planted tank because they will drive the CO2 out of the tank, just when the plants require it the most. If you have no plants then it does not matter and they do add O2 to the tank. A good aquarium will measure o2 between 5 and 7 milligrams according to Barron's Aquarium Plant Manual, Ines Scheurmann is the author. A fish manual states the same figures and also says more than this will cause the O2 to leave the aquarium as a gas. So if you are measuring O2 then shoot for between 5 and 7 milligrams of O2.

90 gal tank
Down at the moment.
29 gal
Emperor 400
HOT Magnum ( I know you abbreviate HOB but since the proper name is H.O. T. and I do not necessarily hang it on the back, but perhaps side especially when I use it on the 90 gal, on the side and to clean a tank briefly I may hang it on the front.
7 Wag Tail Platys 4 are almost 2 inches long the others over an inch.
7 Zebras (Danios)
4 Danios that are probably morphs of the Zebra, they have a very small body with a large fantail and have the Zebra stripes. These maybe still very young and may grow larger.
2 100 watt heaters both set on 75 deg. F. Just in case one goes out.

And I must move over to the Pond forum as I have a pond and an overload of plants and gold fish, some fancy.

 

[Guest]

This reminds me of the saying "if it ain't broke don't fix it"

Still, if you are that concerned with O2 in the water, either a bubble wand or a surface agitator attachment to your filter should have your tank bursting with O2. I took the surface agitator attachment off my 304 because the tank was so full of tiny bubbles that it ruined the clarity of the water. Now I have nothing adding O2 to the water except the gas exchange on the surface of the water, but my fish are not complaining.

 

[greenmaji]

I think the issue was to avoid surface aggitation to keep the CO2 in the water for the plants while having enough dissolved O2 possibly O2 saturation for the fish and bio-filter's bacteria, and the plants during lights out.
the only problem adding O2 is the normal methods of adding O2 cause surface aggitation causing the CO2 to escape and equalize with the CO2 that is in the room that the tank is in.. if O2 is dissolved into the water this is no longer a problem.. the only limit to how much O2 that could be added would be the saturation point of the water in the tank.. I cant see how it could drive CO2 out of the water..

one option is to set a air pump on a timer to avoid O2 depravation during lights out or closer to the dawn period..
my theory there is to dissolve the O2 into the water in the same methods as you would CO2 eliminating surface aggitation..
or using a PH controller and pressurized CO2 system to minimize the CO2 added to the system.
good luck caudelfin

 

[Jchillin]

My knowledge is ever increasing due to AA.

My research advised me of the following regarding planted tanks:

1. Canisters/Sumps with submerged outflows are preferred as they reduce surface agitation and CO2 loss.

2. Bubble wands and/or HOB's diffuse so much CO2 that plants can starve so the emphasis was not to use them.

3. The delicate balance of light, O2 and CO2 is extraordinary in planted tanks due to the smaller environment and aquarists trying to duplicate the processes of natural occurrences, hence CO2 injection, dosing ferts, etc.

That being said, I can certainly understand what is being attempted here. I just don't see where trying saturation via the canister is viable at this time.

 

[chasgood]

So if I decrease the surface aggitation the plants do better.
I have always tried to keep a good surface aggitation in the 37gl because of its low surface area. Maybe I went to far with it. Will point the spraybar down a bit and hope my plants grow better.

For your sometimes overstocked tank maybe turning the CO2 off at night might be the answer as the plants are giving off CO2 at this time. Or did I get that wrong?
Or maybe run the bubble wand on a timer the last hour or 2 of night time.