# Annual risk of gas embolism from water changes



## Chromedome52 (Jul 25, 2009)

We are approaching that time of year when massive water changes carry the added risk of gas embolism. Even if you mix hot-cold from the tap to match your tank temperature, it still carries more gas than usual because cold water holds more dissolved gas, and this increases when that water is under pressure. As it degasses in the tank, bubbles can form in the tissues of the fish. If such bubbles accumulate in the wrong place, such as in the gills, it can cause "mysterious" fish deaths.

Contrary to what some think, this is not just theoretical; Jim Langhammer dissected specimens and found this to be the cause, resulting in an article that many clubs reprint in their bulletins at this time every year. If the name isn't familiar, do a little history research on the early formation of the ACA, the ALA, and the first spawnings of freshwater stingrays in public aquaria. He was doing 70% water changes - every three days - using one of the most amazing water change systems I've seen. So the risk is specifically tied to large water changes, though I believe they could be much smaller than 70% and still carry a lot of risk.


----------



## GTZ (Apr 21, 2010)

Fascinating subject. Good reading here.


----------



## mambee (Apr 13, 2003)

I had a Festivum that got a large gas bubble behind one of his eyes after a large water change. I also lost 5 of 6 Clown Loaches another time. They were rocketing around the tank and hitting the lid.

How can I perform large water changes on a large tank and avoid this problem?


----------



## Chromedome52 (Jul 25, 2009)

The only safe way to change a large percentage of water is to put it in an unpressurized container and let it "age". Warming and/or agitating the water in the container can speed the outgassing.

Langhammer had several plastic 50 gallon drums for letting the water gas out, and an elaborate electronically controlled water changer that was years ahead of its time. I have three plastic barrels that are from a local apple cider/vinegar producer, cost me $20 apiece several years ago. A small submersible pump and a hose works to move the water from the barrels to the tank, or the barrels can be set up high to allow gravity to work.

Reverse Osmosis also filters out most of the dangerous gasses, but it's usually too slow.

On my 125 in the living room, I have a small feed line and an overflow drain, so I can leave it run at a slow rate for several hours at a time. You would be surprised at how much water can be turned over this way. This also adds right next to my HOB, so the water is mixed and agitated at the same time, speeding the process of gas exchange/release.


----------



## mambee (Apr 13, 2003)

I live in a 2nd floor apartment, so having barrels wouldn't work for me. I try to keep the end of the Python above the water level when refilling the tank, hoping that this will help dispel some of the gas.


----------



## Nodalizer (Nov 7, 2011)

I wish it was that time of year.

Stinking hot over here in auzzy land.


----------



## Brookforest_Lane (Mar 31, 2010)

Chromedome52 said:


> The only safe way to change a large percentage of water is to put it in an unpressurized container and let it "age". Warming and/or agitating the water in the container can speed the outgassing.
> 
> Langhammer had several plastic 50 gallon drums for letting the water gas out, and an elaborate electronically controlled water changer that was years ahead of its time. I have three plastic barrels that are from a local apple cider/vinegar producer, cost me $20 apiece several years ago. A small submersible pump and a hose works to move the water from the barrels to the tank, or the barrels can be set up high to allow gravity to work.
> 
> ...


I also use a similar setup utilizing a 55 gal plastic drum and a submersible pump. This allows me to premix my homemade cichlid salts/buffers to keep the PH/GH/KH constant. In addition, I allow the water to age overnight to bring it to room temperature and hopefully remove any dangerous gases.


----------



## Number6 (Mar 13, 2003)

*mambee*

Where I now live, this isnt an issue... But back when i had well water, this was an issue. I took an old aquaclear filter and hung it on all tanks for my water changes. As new water came into the aquaclear it entered the bottom of the aquaclear, up through some activated carbon and trickled down into the tank. Even large water changes had no effect on the fish. I never did know what the levels of gases were nor what gases there were so no idea if my success would translate to your success.


----------



## GTZ (Apr 21, 2010)

Bump


----------



## joeyo (Jul 2, 2012)

Chromedome52,

So are you saying that you cannot use tap water directly to refill your tank durring weekly water changes unless you let the water sit for a few hours/days? I have city water that is a pretty good ratio in terms of ballance and no heavy minerals or other impurities that would cause impact. I use a wet dry fiter and have only been managing this since July of 2012, is this an immediate issue or one that would impact the fish over a long period of time - like 4 to 6 months from continued use?


----------



## 13razorbackfan (Sep 28, 2011)

GTZ said:


> Bump


Thanks...

Since I do weekly 85% water changes on my tanks I find this very interesting.


----------



## DJRansome (Oct 29, 2005)

It's a temperature thing. So if you use 78 degree water you are fine. I you are using cold and doing smaller water changes this could be an issue.


----------



## kmuda (Nov 27, 2009)

13razorbackfan said:


> GTZ said:
> 
> 
> > Bump
> ...


What is it about us Arkansas boys and large water changes. I perform weekly 85% plus water changes on all of my tanks as well. I commonly perform 100% water changes on tanks with sumps by filling the sump while draining the main tank, allowing the sump to continue pumping back to the main tank.


----------



## 13razorbackfan (Sep 28, 2011)

kmuda said:


> 13razorbackfan said:
> 
> 
> > GTZ said:
> ...


Not sure. I have done this for years and years and I think we are lucky enough to have access to good clean water with minimal chlorine and chloramines.

PS...do you also get the yearly Ft. Smith water report as well? We have very very good water. Knock on wood.


----------



## kmuda (Nov 27, 2009)

13razorbackfan said:


> PS...do you also get the yearly Ft. Smith water report as well? We have very very good water. Knock on wood.


Yes.... Fort Smith has VERY good water. It won "Best in State" a couple of years ago and was competing for "Best in USA", although I don't know the end result.

We are good as long as water comes from Lake Fort Smith. Not so good if they have to shift back over to Lee Creek.


----------



## 13razorbackfan (Sep 28, 2011)

kmuda said:


> 13razorbackfan said:
> 
> 
> > PS...do you also get the yearly Ft. Smith water report as well? We have very very good water. Knock on wood.
> ...


Yep....

Again...knock on wood.


----------



## mhertzfeld (May 19, 2012)

What about those of us that live further north?

I have no other choice but to add water directly to the tank (I try to get it as close to 78 as possible but that's mixing cold water and water heated by my tanklesss water heater together in the bathroom sink with the python)

Anything I can do other than let the water age, which at this point is not an option? I have city water which runs through miles of pipe before it reaches my tap.


----------



## kmuda (Nov 27, 2009)

My python has a ball valve on the outflow end that allows me to adjust the pressure of the outflow (think thumb on the end of a water hose). If you can do the same, and force the water out under a pressurized spray aimed at the front wall of the aquarium so that the water flows down the glass (see the below pic), this should help stabilize gas content of the water. I do it because my tap water is void carbon dioxide and low in O2. This action helps the water absorb both from the atmosphere while also giving free chlorine a chance to escape into the atmosphere. Chlorine is a gas and like any gas that can cause gas embolism, it wants to escape into the atmosphere. Water wants to reach a natural equalibrium. Give it a chance and it will.










Absent the ball valve on the end of the Python, something else I've done in the past is rig up a fine mesh pasta strainer so that the refill water goes into the strainer, where it is broken up into hundreds of little streams by the mesh before it reaches the tank, which accomplishes the same purpose.


----------

