Lost 7 fish within 1 hour of water change

FuzzAz

I did a water change in three of my tanks, and I looked at my tanks an hour later. lost 2 black skirt tetras and a white cloud in one tank, and in another tank I lost 2 neon tetras and 2 puenguin tetras. not really sure what happened here. Im thinking it might have somthing to do with my new water changing tool, that and pressurised CO2 arethe only recent changes.

http://www.fishforum.com/diy-aquariu...ictures-21531/

cerianthus

New additives in tap a possibility?
CO2 injection on all tanks?
ph, NH3, No2?
Nice DIY . I am sure you are using dechlorinator, matching temp before adding and even so would rather have new water splash onto top surface, Hope you didnt to more than 25%?
I always had reserve circulation 24/7 but always ran tap for while before collecting in reserve and used cold water only with submersible heater.

Fishcricker

Could it have been a pH shock?

FuzzAz

Both tanks that had fish loss are CO2 injected, however prior to the pressurized system I had a DIY system so CO2 is not new. but I was under the impression that pH change due to change in amount of dissolved CO2 wasn’t an issue.

"normal" pH in all my tanks is 8.0 to 8.2, my injected tanks run at 7.2
nitrate10ppm
I cant find my nitrite test, I’m not to worried about it. my tanks are cycled and heavily planted.
ammonia 0

I changed about 30-40% of the water, I don’t know exactly, I run the pressure and the siphon at the same time. the water moves at a rate of 1.5gpm. for about 10 minutes in my 37 gallon and 5 minutes in my 20 gallon. of course I matched the temp.

I don’t add dechlorinator, I have not for over a year. I checked a long time ago and checked again more recently. There are no chemicals including chlorine or chloramines added to my water.

I notice the abundance of bubbles on leaves and glass after a water change, I wonder if that has something to do with it. if bubbles got in their gills?