Gases in water changes?

[Ron Sower]

Yesterday I did a 60% WC in my community 55g. Lots of little bubbles on the glass and large leaved plants as usual, but way more than normal. I use straight tap water, as always, with no chlorine treatment. I left the house for a couple hours and returned to a tank finding 18 out of 22 of my school of Ember Tetras dead. No signs of disease that I can tell. The rest of the fish were sluggish and just milling around.  This morning, observing with a flashlight, I see that the inhabitants are doing well...including the BN's with the new clutch of eggs from last night's breeding. My White Clouds are fine and schooling together. And all the miscellaneous species seem okay.

Can someone explain how the winter cold water may have caused this?
Or any other ideas?

I won't be doing such large WC's in the winter months any more...!!

Geez...I hate loosing the Embers suddenly like that. I've been collecting this group over several years.

[Mugwump]

Yesterday I did a 60% WC in my community 55g. Lots of little bubbles on the glass and large leaved plants as usual, but way more than normal. I use straight tap water, as always, with no chlorine treatment. I left the house for a couple hours and returned to a tank finding 18 out of 22 of my school of Ember Tetras dead. No signs of disease that I can tell. The rest of the fish were sluggish and just milling around.  This morning, observing with a flashlight, I see that the inhabitants are doing well...including the BN's with the new clutch of eggs from last night's breeding. My White Clouds are fine and schooling together. And all the miscellaneous species seem okay.

Can someone explain how the winter cold water may have caused this?
Or any other ideas?

I won't be doing such large WC's in the winter months any more...!!

Geez...I hate loosing the Embers suddenly like that. I've been collecting this group over several years.

Winter cold water in your pipes becomes super saturated ....the fish are effected through their gills when breathing.....

[BillT]

More details:

Cold water can hold a lot more dissolved gas than warm (fish temp) water.
Water under pressure can also hold a lot more dissolved gas than water at atmospheric pressure.
Combined your tap water in cold periods can hold more dissolved gases (presumably the gas comes from bubbles in the pipes supplying your house).

The water comes out of the tap, drops in pressure and gets warmed up --> supersaturated (too much dissolved gas in water, some has to come out (as bubbles)).

Fish will often go to the bottom of the tank where the pressure is greatest and where the effects of supersaturation will be greatest.
Sometimes you can see small bubbles behind the eyes or under the skin in the fish's body (may require a microscope).

Work arounds:
? let water sit around to degas.
? aerate water (bubble, spray, trickle, or shake water in a container with a lot of air contact)
? make only small water changes of to limit the amount of supersaturated gasses introduced into your tank (you can do many WC's per day though)

[Mugwump]

More details:

Cold water can hold a lot more dissolved gas than warm (fish temp) water.
Water under pressure can also hold a lot more dissolved gas than water at atmospheric pressure.
Combined your tap water in cold periods can hold more dissolved gases (presumably the gas comes from bubbles in the pipes supplying your house).

The water comes out of the tap, drops in pressure and gets warmed up --> supersaturated (too much dissolved gas in water, some has to come out (as bubbles)).

Fish will often go to the bottom of the tank where the pressure is greatest and where the effects of supersaturation will be greatest.
Sometimes you can see small bubbles behind the eyes or under the skin in the fish's body (may require a microscope).

Work arounds:
? let water sit around to degas.
? aerate water (bubble, spray, trickle, or shake water in a container with a lot of air contact)
? make only small water changes of to limit the amount of supersaturated gasses introduced into your tank (you can do many WC's per day though)

Thanks, Bill...

[Ron Sower]

Yes, Bill...Thank you!

I normally disengage my canister filter during the WC so that it doesn't lose it's siphon when the water level goes below the intake. What I now realize that I did differently, is that I forgot to re-engage it for the water movement/agitation/shaking/aeration.

Damn!...Sometimes I'm a dumkopf..!

[wsantia1]

Yes, Bill...Thank you!

I normally disengage my canister filter during the WC so that it doesn't lose it's siphon when the water level goes below the intake. What I now realize that I did differently, is that I forgot to re-engage it for the water movement/agitation/shaking/aeration.

Damn!...Sometimes I'm a dumkopf..!

Damn. I've done that too and lost a nice pair of Angels. It sucks.

[Mugwump]

Yes, Bill...Thank you!

I normally disengage my canister filter during the WC so that it doesn't lose it's siphon when the water level goes below the intake. What I now realize that I did differently, is that I forgot to re-engage it for the water movement/agitation/shaking/aeration.

Damn!...Sometimes I'm a dumkopf..!

Damn. I've done that too and lost a nice pair of Angels. It sucks.

..don't let your refill hose be submerged....the splashing helps too on this...even slapping the water off a tank wall helps release the gases....experiment a bit..

[Ron Sower]

Yes, Bill...Thank you!

I normally disengage my canister filter during the WC so that it doesn't lose it's siphon when the water level goes below the intake. What I now realize that I did differently, is that I forgot to re-engage it for the water movement/agitation/shaking/aeration.

Damn!...Sometimes I'm a dumkopf..!

Damn. I've done that too and lost a nice pair of Angels. It sucks.

..don't let your refill hose be submerged....the splashing helps too on this...even slapping the water off a tank wall helps release the gases....experiment a bit..

I'm conjuring up a design for my refill hose now. Thanks Mugs. Another project!!!!!

[BillT]

I have had this problem many times in the past in university fish rooms that were set-up to rely on flow through of tap derived water to take care of their water quality.
They had lots of problems in the winter when the water was cold.
When we got more money we designed it away. Basically aerated it in a tub before using it.
Many small water exchanges (using an automated system) or some kind of a sprayer (for manual WC's) would probably be good solutions.

[Ron Sower]

I have had this problem many times in the past in university fish rooms that were set-up to rely on flow through of tap derived water to take care of their water quality.
They had lots of problems in the winter when the water was cold.
When we got more money we designed it away. Basically aerated it in a tub before using it.
Many small water exchanges (using an automated system) or some kind of a sprayer (for manual WC's) would probably be good solutions.

When I get the custom tank in, I will be able to do many small water changes easily and that should fix it. The fact that I haven't had the problem before tells me that the filtration I currently have is enough for the aeration.  Wouldn't you think that?  Key is I should remember to engage it once I'm through the change.

[BillT]

Probably so.

Its a balance between:
how saturated the incoming water is
how big % the water change is ((amt added/tot volume)*100)
and how fast and effectively your water system aerates the water
the tolerance of your fish

[Ron Sower]

I have had this problem many times in the past in university fish rooms that were set-up to rely on flow through of tap derived water to take care of their water quality.
They had lots of problems in the winter when the water was cold.
When we got more money we designed it away. Basically aerated it in a tub before using it.
Many small water exchanges (using an automated system) or some kind of a sprayer (for manual WC's) would probably be good solutions.

When I get the custom tank in, I will be able to do many small water changes easily and that should fix it. The fact that I haven't had the problem before tells me that the filtration I currently have is enough for the aeration.  Wouldn't you think that?  Key is I should remember to engage it once I'm through the change.

Thanks Bill.

[BillT]

I'm not familiar with your filtration set-up, but if you have a trickle bio-filter step, you could run your supersaturated water into that. They are very effective gas exchangers. Engineers have told me that 4.5 feet of trickle filter will put the dissolved gasses in the water completely at equilibrium with the gasses of the atmosphere it is being exposed to. A small trickle filter would probably take a lot of the edge off of the supersaturation exposure.

Here's another thing you could do depending on the volume of your water exchange:
Get a fish safe (inside and out) bucket. (This could probably be done with some kind of large bag or piece of plastic.)
Float it in the tank in which you want to water exchange.
Fill the bucket with the supersaturated water so it floats but is mostly full.
During this time (or before) you should have had water removal going on in some way (I have bulkhead drain connections, so the raising water int he tank would just flow out as it was displaced by more water going into the bucket).
Secure it in some way and throw in an airstone. Turn the air on high.
Come back in an hour and release the water into the tank. It will also be a better temperature match.

Or connect a big tube to the end of your water supply hose. Fill it with some biological filter media (chunky is better), put a screen on the end.
Shoot your fill water through this at a rate and angle that leaves a lot of air in the tube but spreads it across it fu;; cross section. This will be a mini-trickle gas exchanger. Air has to be able to go in each end.

[Ron Sower]

I'm not familiar with your filtration set-up, but if you have a trickle bio-filter step, you could run your supersaturated water into that. They are very effective gas exchangers. Engineers have told me that 4.5 feet of trickle filter will put the dissolved gasses in the water completely at equilibrium with the gasses of the atmosphere it is being exposed to. A small trickle filter would probably take a lot of the edge off of the supersaturation exposure.

Here's another thing you could do depending on the volume of your water exchange:
Get a fish safe (inside and out) bucket. (This could probably be done with some kind of large bag or piece of plastic.)
Float it in the tank in which you want to water exchange.
Fill the bucket with the supersaturated water so it floats but is mostly full.
During this time (or before) you should have had water removal going on in some way (I have bulkhead drain connections, so the raising water int he tank would just flow out as it was displaced by more water going into the bucket).
Secure it in some way and throw in an airstone. Turn the air on high.
Come back in an hour and release the water into the tank. It will also be a better temperature match.

Or connect a big tube to the end of your water supply hose. Fill it with some biological filter media (chunky is better), put a screen on the end.
Shoot your fill water through this at a rate and angle that leaves a lot of air in the tube but spreads it across it fu;; cross section. This will be a mini-trickle gas exchanger. Air has to be able to go in each end.

Thanks again Bill. Do you suppose you could photograph your bulkhead fill and drain connections and send it to me?

[BillT]

Here are some pictures Ron:


A common bulkhead (through the tank side) fitting kit (bulkhead parts, strainer and tubing connector). This drains into a bunch of pipes that lead to a floor drain.

Strainer:


These have the bulkhead located high on the tank, so the water just goes sideways through the hole into the pipe to drain out. Alternatively, you could put the bulkhead lower down on the side and stick one of the angled tubing adapters into the inside side of the bulkhead and put a long piece of tubing on it pointing up. The overflow point becomes the lowest point of the top of the tubing. This would let you have a level of water that is higher up than the bulkhead hole. If you wanted to remove a lot of water painlessly you could then remove the angled adapter and the water will drain to the level of the hole.

or a piece of sponge filter for smaller fish:


Bulkheads require drilling holes in glass. Not for everyone.
A friend of mine, Dennis Goof, uses a different drainage system that uses siphons to get the water out as it raises rather than a hole in the tank. Easier to set-up but requires no air in the  siphons. Tubing is used to suck out  the inevitable bubbles that can stop flow out and cause overflows. The overflow level in this system is moved out of the tank to place on the right where the drain tube rises up, has a vent, and then goes down. The level at which the water can flow over this dam to flow determines the tank's water level. On Dennis's rack, the hole shelf is controlled by one of these overflows. Things that can get into the drains can swim from one tank to another on the row. Use screening.


Supply lines (air and water). Metal valves: air; plastic valves: water.