O2 and Temp

[buckry]

My water is consistenly between 68 and 70 degrees F, is this a fairly safe temperature or is this borderline for O2? I had added 2 aerators and an extra pump last week to combat the heat, but since the water temp didn't really change I think I was just wasting electricity. Anyone else agree with that? I have 4000gph flowing over a 2' sheet waterfall and a small splashy waterfall and stream, and I have 70 degree water, is this flirting with disaster or do I have plenty of buffer to combat any issues that might arise.

Also, I know everyone said they don't test for dissolved oxygen, and that meters are expensive, but Cabella's has one for $60. I have one on order, I will let you know how it works. Reviews are mixed, but it's worth a shot for me.

http://www.cabelas.com/boating-accessories-procatch-50-oxygen-temperature-meter-1.shtml

 

[taherrmann4]

Are temping your water temp in the morning, afternoon or evening? When I temp mine in the evening it has been about 85 degrees. I have a 7200 gph pump in my 3,000g pond and one pond aerator. I have a pretty good size waterfall that falls over 7 rocks so there is also plenty of good aeration coming from that as well as my other two creeks that are flowing over some rocks. I haven't had any issues over the years and last summer there were days that my water reached close to 90 in the afternoon. My fish have never shown any signs of distress. It is currently about 30% covered with lilies, lettuce and other plants to try and keep it cooler, but this year has gotten hot so early!

 

[buckry]

I'm measuring only at the water's surface farthest away from the waterfall, and it's usually 67 or 68 in the morning, and 69 or 70 in the evening. It's really rock solid, even on those 100 degree days it never went above 70. I'm debating sending my thermometer to the bottom today, but I might just skip that since I have a digital one coming.

 

[buckry]

Good to know though, your experiences are definitely what I would expect. Thanks.

 

[buckry]

I did read last night during some research that sheet waterfalls are good because they can send a lot of water deep into the pond, and that when bubbles are formed gas is transferred, and it is transferred again when the bubbles pop. Sheet waterfalls create lots of bubbles and send those bubbles deep into the pond. I am probably getting an extra foot of gas exchange under water from my waterfall, so my fall is probably close to 3' tall if this is all true.

 

[Waterbug]

A water fall passing thru 100F air...pumping 100F air thru an air pump and thru the pond...and your expectation is your 70F pond is going to get cooler?

I've explained how gas exchanged happens in a pond more times than I'd like, there are many web sites that explain it...but water gardeners have always and I think will always believe crashing water over rocks is how O2 gets into ponds. So I give up on that point.

As for a water fall pushing water deep into a pond...nope.

 

[buckry]

Ok, so that website is a liar for using the word "deep" but the last time I was in my pond I put my hand under the sheet and I could still feel motion 12" down, so those bubbles have to be doing some good when they are created.

Not sure about the pond temp thing you mentioned, I'm not concerned about it changing, I've measured it every morning and night for a week, it hasn't changed. Can it change, yeah, I'm sure it can. Will it, again yeah probably, but for now it's 70F and that's the starting point for the information I'm looking for.

I just want to know how effective that exact temperature is compared to 60F and 80F. Obviously it's halfway between, I just want to know if it's a fairly safe number.

 

[minnowman]

Overstocking or overfeeding are the main causes of low oxygen levels. The effect of temperature is relatively small. The water temp in my Koi pond has been in the mid to upper 80s for several weeks with no adverse effect on the Koi. The metabolism of fish increases at warmer temps so the fish will eat more. In an overstocked pond, excess feeding results in lower oxygen levels . Fish gulp surface water where oxygen level is highest and bacteria in a biofilter stop converting ammonia to nitrates. Ammonia further stresses the fish. This can result in immediate mortalities or longer term illnesses.

 

[brandonsdad02]

A water fall passing thru 100F air...pumping 100F air thru an air pump and thru the pond...and your expectation is your 70F pond is going to get cooler?

I've explained how gas exchanged happens in a pond more times than I'd like, there are many web sites that explain it...but water gardeners have always and I think will always believe crashing water over rocks is how O2 gets into ponds. So I give up on that point.

As for a water fall pushing water deep into a pond...nope.

I know that you "think" that a bubbler is the best way to get O2 into water, but from trial and error, breaking the surface of the water with a waterfall or something of that sort works. I have a bubbler in my pond in the deep end to help bring the water up to cycle the water. From my waterfall, the stream and my bog, the O2 in my pond is great. My temp is 86* and my fish are showing no signs of distress. They are very active and growing. All of my plants in the pond are lush green and exploding in size.

Your theory doesn't really hold true. In northern Iowa we have some of the best trout streams in the area. The DNR doesn't put bubblers in the streams, there are waterfalls and fast moving water at least every 1/4 mile of stream. Trout must have cool water with high O2 levels.

With your theory of water passing thru 100* air it won't cool. I guess we better not go outside when its 105* or hotter because we won't be able to stay cool. I mean if water heats up passing thru air, then our bodies will heat up too right? Each breathe of air we breath in, we heat up.

 

[brandonsdad02]

Ok, so that website is a liar for using the word "deep" but the last time I was in my pond I put my hand under the sheet and I could still feel motion 12" down, so those bubbles have to be doing some good when they are created.

Not sure about the pond temp thing you mentioned, I'm not concerned about it changing, I've measured it every morning and night for a week, it hasn't changed. Can it change, yeah, I'm sure it can. Will it, again yeah probably, but for now it's 70F and that's the starting point for the information I'm looking for.

I just want to know how effective that exact temperature is compared to 60F and 80F. Obviously it's halfway between, I just want to know if it's a fairly safe number.

As long as your fish are active and healthy, you shouldn't have a problem. I've read somewhere that once your water starts getting above 90*, you might start seeing problems and should look for ways to find shade for your pond and your fishies. I would love to have 70* water right now. I'm currently at 86*

 

[buckry]

Fair enough. Once my O2 meter shows up I'll certainly do some test and get some data, so maybe I'll be able to clear this up for everyone.

 

[crsublette]

I am likely missing some references. Grr, I got 50 or more bookmarks. I am gonna start organizing them. Sucks having to search for everything everytime I am wanting to share the info.

So, this is what I know at this moment ... always learning from corrections and more reading

--------------------------


Weather here has stayed a few hours in the 102~105* F for 5 days and our lo-temp never dropped below 68~70*F. My water temp has been 78~80*F. I have just a couple air diffusors. Also, most of my water is pulled from the bottom, where it is cooler, to the top; this probably keeps the temperature up. Also, the water is in partial shade due to big cedar elm trees preventing the water from heating up much higher.

-----------------------------------

In northern Iowa we have some of the best trout streams in the area. The DNR doesn't put bubblers in the streams, there are waterfalls and fast moving water at least every 1/4 mile of stream. Trout must have cool water with high O2 levels.

I bet the stream water is very cold. Trout are cold blooded and species of Trout dictate DO demand. Google "trout dissolved oxygen". I bet those streams are not closed systems. I bet open system streams constantly have the water refreshed with the highest possible O2 saturation at all times unless there is a dead zone in the stream.

Water temperature is not the same at all depths. Water temperature dictates maximum O2 saturation. Cold water dictates very high O2 saturations. Warm water dictates very low high O2 saturations.

Koi, comets, and many other hardy fish are cold blooded fish. Cold blooded fish's DO demand is dependent temperature since their body metabolism is mutually exclusive with water temperature. Feeder goldfish (also called comets) don't need much O2. You can often find comets in algae covered sections of lakes. Comet, feeder goldfish often found to live in dissolved oxygen (DO) levels of 5mg/L where as more demanding fish such as an adult Koi need 8mg/L or higher.

Koi grow very fast. So, their DO demand is obviously higher when the water temperature increases their metabolism. Pretty simple. Comets are much more hardy since they grow extremely slow.

Dissolved Oyxgen - Koi Club of San Diego
maximum O2 staturations for freshwater
90* F water = 7mg/L DO
70* F water = 9mg/L DO
45* F water = 12mg/L DO
35* F water = 15mg/L DO

Salinity further decreases possible saturation levels.

Floating plants ... Think about this and how atmospheric pressure adds O2 to water. Rivers become severely oxygen depleted due to floating plants. Floating plants may help cool the water, but they also help deplete O2 levels. Do a google search about when floating plants become dangerous, killing aquatic life.

---------------------------------------------

I know that you "think" that a bubbler is the best way to get O2 into water, but from trial and error, breaking the surface of the water with a waterfall or something of that sort works.

Waterfall pushes the top O2 saturated water to the depths of the water where water is less oxygenated. Sheet waterfalls pushes oxygenate water down and creates small bubbles that help stir the water. Cascading waterfalls only oxygenates water at a very shallow depth.

-------------------------------------


Ammonia Toxicity increases with water Temperature.

 

[brandonsdad02]

Yes, those streams are cold. They a spring fed so they remain the same temp year round. The best fishing I've had have been during the winter. Even tho the air temp might be 95 the stream temp is around 54 even tho the hot air passes through the water in the waterfalls.

 

[crsublette]

I doubt Waterbug was suggesting that the hot air from aerators would cause dramatic, nor even noticeable, heating of water. His humor was only pointing out how hot air does not help with cooling, and I bet buckry knows this.

 

[buckry]

Hey look at that, that's the answer I was looking for:

70* F water = 9mg/L DO

So I would say that does give me some buffer, so no need to worry if a pump fails or if the temp climbs.

Thanks a ton, that's exactly what I was looking for, tried 50 PDF's today and never saw that one little tidbit.