Ok to water change in winter??

[chase35]

Ok, I have a backyard koi/goldfish pond, about 2000gal. Before the cold set in I put a pump in to move the water around so it wouldn't freeze, then I found out an air pump would be better! So I put one in. I made sure that there was no leaves or other debrie in the pond before it froze over. Well a month later and we have had a "heat wave" 37 degrees, now the pond is thawed out and I have noticed that there is a lot of algae and other crap in the water, the water is green. So my question is it ok to do a 40-50% water change (or several small ones) in winter, or will it shock my fish to much? Which one is better poor water condition or shock from temp change??

Thanx for looking! Have a great day

 

[Andrew McFadden]

It should be fine
If your using warmer or colder water adding it back in slowly will help the fish. Adding the same temp or a degree off shouldn't affect them at all.

 

[jlk]

Have you actually tested the water parameters? How do they look? Green water by itself is not a big concern even if it is unsightly.

I'm not sure what you mean by you added an air pump so the pond can freeze over over. Adding aeration isn't a concern with a frozen pond but having even a small open area so toxic gasses can be released is. Cold water is saturated with lots of dissolved oxygen- no worries about this. A small deicer would be better idea or keeping a small pump running that breaks the surface to limit freezing works for some as well.

 

[chase35]

Let me start by saying sorry for taking so long to reply!
I have tested the water, and it seems to be next to perfect

Carbonate hardness 7dkh-125.3ppm
Phosphate 0ppm
Ammonia 0ppm
Nitrite 0 ppm
Nitrate 0 ppm
Ph 7.3-7.4 ( hard to tell between colors)
Oxygen saturation 9 mg/L (ppm) +\- .5 mg/L

The reason why I added an air pump was to break the surface of the water so it WOULDN'T freeze, and because of the amount of floatys in the water. I did not want my koi or shubunkin to be laying next to decaying matter that was releasing toxic hydrogen sulphide gases!

If the green water is unsightly but ok for my fish, then all is good.
But what about all the floating matter? It looks almost like the algae or seaweed I feed my saltwater fish.

Thank you to those who replied!!

 

[jlk]

Your numbers look fine so I wouldn't be overly concerned with some green water. If you want to do some water changes, thats fine but i would keep them smaller so the water temp stays reasonably close. Not sure what the floaty stuff is but if you can net it out, I would before it freezes over. As long as your keeping even a small area free of ice, your fine!