Oxygen level meter?

[sueandherzoo]

We test for all kinds of things in our water, but is there a way to test the oxygen level? I'm trying to make sure I have all the stuff I need to keep these tanks running as healthy as possible and am about to order a TDS indicator but wondered if there is some way to see if there is enough oxygen in my water, too. Since a lack of oxygen is what I think killed my first few fish I really want to stay on top of that, if possible.
Sue

 

[spiderwoman]

As long as you have enough surface aggitation, you should be fine without testing your oxygen levels. I think it's waste of money to buy one of those testers. Make sure the surface level of your water ripples.

 

[nycbob]

like spidey said, if u hv water agitation, ur oxygen level should be fine. u can achieve this by pointing ur powerheads toward the water at a 45 degree angle. also, lower temps will increase oxygen level in water. i keep mine at 76-78.

 

[sueandherzoo]

I now have "rippling" on all my tanks so I guess I should relax, but if there were a piece of equipment (that wouldn't cause me to refinance the house!) that I could have around it would be good for experimental/learning purposes, to see exactly how much of a difference water temp, salinity, and other factors affect the oxygen levels.
Sue

 

[natclanwy]

Definitely not needed but if you still want to get a test kit Red Sea and Lamotte both make a dissolved oxygen test kit for saltwater tanks.

 

[sueandherzoo]

Thanks for the info - I'll go do a search and see how complicated/expensive these testers are. I"m a little surprised, though, that not more people here own one or suggest owning one since oxygen is such a critical and variable factor in saltwater tanks. We test for everything else - it just made sense to me that we'd want to keep an eye on the oxygen levels, too. Guess that's a newbie's thinking.

Sue

 

[spiderwoman]

When you have your temp and other levels in check, worry about oxygen levels it the last thing in anybody's mind. It's very rare to lose livestock because of that. What I mean if your temp and flow are in place, the loss of livestock is not because of oxygen levels. If your temp is high, there is less oxygen in the water etc.

 

[natclanwy]

I have been curious about what my actual DO level is here lately only because I am trying to find an explanation for a chronically low PH. If you have good flow DO is rarely a problem unless you have excess amounts of CO2 in your home. You can check for excess CO2 by putting some water from your tank into jar and take it outside put a cap on it shake it then remove the cap and repeat three times then check the PH of the water in the Jar if the PH goes up you have an excess of CO2 in your tank.

 

[sueandherzoo]

I guess I'm paranoid because I think I DID lose 5 fish all due to low oxygen levels. My first learning/experimental 12 gallon Eclipse could not keep a fish alive, even though snails, crabs, and feather duster did fine in there. I would buy a fish and 3-5 days later it would be dead. Ammonia, nitrites and nitrates were all good. We've never been able to figure out why I couldn't keep a fish alive in that tank and I'm in the "experiment" phase now of trying to narrow down the problem. I took the water out of that tank and put it in a bare QT tank, put in a fish, and he's been doing great. I'm leaving the original live rock and live sand in the "killer" tank and am now letting that cycle a week or two with newly RO'd/DI'd, salted and bubbled water and will again try a fish in there.
The only logical conclusion we've been able to come up with is that this tank didn't have enough oxygen in it. Why else would snails live and not fish? And I have since learned the probable reason why there wasn't enough oxygen in there was because I didn't have a powerhead in my holding tank of water change water. I was always adding RO salted water that had been sitting idle for 24 hours, NOT moving or getting agitated. And when the fish in the tank would start to look lethargic and gasping the first thing I would do was a big water change, thus, probably robbing him of even MORE oxygen with the un-oxygenated water.
That's the reason I'm so interested in water oxygen levels - I want to finally find out what was killing all the fish in there and would like to see how much of a difference it makes having a powerhead in the "holding tank" water versus not having one. If there is a big difference, I probably have my answer, but I didn't want to sacrifice another life to conclude that.
Sue

 

[big]

Sue, I think the above advice is all one needs............
But I am pretty sure of seeing the Salifert dissolved oxygen test kits for about 30 bucks at a LFS a while back .....I think Red Sea has test strips too......... Must be on a Google search then I would guess........ If you want to fix the curiosity issue let us know the results................

 

[sueandherzoo]

Yes, actually, for my own peace of mind, I would love to know what killed those first few fish I bought. I won't consider it a total loss if I can at least LEARN something from my mistake, but I need to know what the mistake was before I can give that chapter closure.
Thanks for the suggestions.... I will look online and let you know if my results show anything drastic.
Sue

 

[big]

Sue one last question.
Quote from you
"""I was always adding RO salted water that had been sitting idle for 24 hours, NOT moving or getting agitated. And when the fish in the tank would start to look lethargic and gasping the first thing I would do was a big water change, thus, probably robbing him of even MORE oxygen with the un-oxygenated water"""
The water you where-are using for "top off" ..... replacing what has evaporated......... This is just RO right not RO salted water .....
I remember the first coral book I ever had was published in about 95..... It listed 10 most common mistakes for beginners.... One was adding saltwater to top off for evaporation, I think many have done this not realizing at first the minerals and salt do not evaporate..
What made me think of that, was when you said that your inverts and snails where still alive........ They both can tolerate for a period of time an extremely high salinity....... Salinity should be around 2.04 to 2.06. ...........Just a thought.......Hope you figure out you issue.......

 

[spiderwoman]

Unfortunately you probably will never know what killed them. It's the sudden change in levels that it's hard to catch as it can happen in the middle of the night or when ever. You can't be testing your tank 24/7.

 

[sueandherzoo]

Originally Posted by big
http:///forum/post/2823554
Sue one last question.
Quote from you
"""I was always adding RO salted water that had been sitting idle for 24 hours, NOT moving or getting agitated. And when the fish in the tank would start to look lethargic and gasping the first thing I would do was a big water change, thus, probably robbing him of even MORE oxygen with the un-oxygenated water"""
The water you where-are using for "top off" ..... replacing what has evaporated......... This is just RO right not RO salted water .....
I remember the first coral book I ever had was published in about 95..... It listed 10 most common mistakes for beginners.... One was adding saltwater to top off for evaporation, I think many have done this not realizing at first the minerals and salt do not evaporate..
What made me think of that, was when you said that your inverts and snails where still alive........ They both can tolerate for a period of time an extremely high salinity....... Salinity should be around 2.04 to 2.06. ...........Just a thought.......Hope you figure out you issue.......
Good thought, but no, I kept two separate containers: one was RO water without salt (for top-offs) and one was RO water WITH salt (for water changes). But I can see how that could be a common mistake for a newbie - thanks for the reminder!
Sue

 

[natclanwy]

RO water that has been sitting for 24hrs should not lose a significant amount of oxygen, I and I'm sure there are others keep my water in 5 gallon buckets until I need them and then I just pour the water in my tank they can be sitting for up to two weeks before I use them depending on my water change schedule. I remeber seeing your thread about your fish dieing I'll have to go back and read it and see if I can find something that stands out. I would highly doubt that it is oxygen deprivation that was killing your fish as long as you had some type of circulation in your DT. The only time I have ever seen fish die from lack of oxygen is on a tank that sat stagnet for 2 days due to a blown breaker while a friend was out of town. There are certain chemicals that can deplete oxygen levels also, "Chemiclean Red slime remover" is one that comes to mind.

 

[sueandherzoo]

You say that you don't think RO water can lose a lot of oxygen sitting stagnant for 24 hours but doesn't it have very little oxygen in it to begin with and needs to be agitated to put oxygen INTO the water? Since my water was going from the RO unit to a 5 gallon bucket and then just sitting I figured there wasn't much in there and that was the cause of the fish dying. Actually I was HOPING that was it so that I could finally find my answer.
I've had a yellow watchman goby in a QT tank with the water from the "killer" tank. He's fine. Just tonight I moved him (acclimated him) back to the killer tank that I had filled with RO water that had sat in the bucket with a powerhead for 24 hours. If he does fine in there I guess we'll assume it was lack of oxygen that killed the others. If he starts to fail after 3 days then I will be back to square one but at least knowing it is NOT an oxygen problem.
The mystery continues . . .

 

[natclanwy]

The amount of oxygen in your RO water is dependant on the source, the RO process doesn't remove dissolved oxygen so you should have the same oxygen content after the filter as you did before. Sitting stagnet doesn't cause oxygen to leave the water either oxygen naturally want to dissolve into water so oxygenation is taking place even though the water is not moving just not as effiecently as it would be if it was circulating. In your aquarium you have several organisms that are resperating (taking in oxygen and releasing CO2) so without enough circulation the CO2 will slowly displace oxygen eventually depleting the oxygen from the water or at least from the lower levels of the water if it is completely stagnet. You shouldn't have anything in your RO water that is using oxygen so the amount of oxygen shouldn't change between the time it comes out of the faucet until you use it except to increase in oxygen due to being in contact with the atmosphere.

 

[sueandherzoo]

Originally Posted by natclanwy
http:///forum/post/2824997
The amount of oxygen in your RO water is dependant on the source, the RO process doesn't remove dissolved oxygen so you should have the same oxygen content after the filter as you did before. Sitting stagnet doesn't cause oxygen to leave the water either oxygen naturally want to dissolve into water so oxygenation is taking place even though the water is not moving just not as effiecently as it would be if it was circulating. In your aquarium you have several organisms that are resperating (taking in oxygen and releasing CO2) so without enough circulation the CO2 will slowly displace oxygen eventually depleting the oxygen from the water or at least from the lower levels of the water if it is completely stagnet. You shouldn't have anything in your RO water that is using oxygen so the amount of oxygen shouldn't change between the time it comes out of the faucet until you use it except to increase in oxygen due to being in contact with the atmosphere.

So then why have I so often read and heard that we are to keep powerheads in our water holding tanks? I'm a newbie so I'm not disputing or agreeing - I'm just trying to learn. Some people suspected I lost my fish (5 separate incidences) due to low oxygen in the water, most especially from adding uncirculated RO water.
Sue

 

[big]

Maybe at this point it is time to look for what could be the problem other than a low oxygen level in you partial change water............
As we do this stuff more and more with time, sometimes we just start to take things for granted...... I often let buckets of PC water sit longer than I should too..... They sit in my garage with a power-head and small heater. But there are times that I will have a buckets that has no power-head in them for days. If so I do run a power-head in it for at least an hour or two before adding it to the tank......... But when I do get around to adding the water there are a few things I always do first before adding the water.
One is being sure that the temperature matches to less than a degree difference what is in the tank. Second I do one last check of the salinity........Again I am looking for a near perfect match.............. Any maybe last but maybe the most important. Regardless of the method you use to remove water from the tank. When adding the new water I do it gradually.........Slowly poured in from a small container, like a gallon pitcher. Not just dumped in out of the five gallon bucket like some folks do. Give the tank time to adjust to the water addition.
I know these simple things may sound a bit too simplistic. But is the temperature and salinity, are closely matched a partial change done with adding the new water slowly should not have any adverse effect on the critters in the tank................. One last thing would be, more small changes more often as opposed to large changes less often. I have a total water volume of about 120 gallons in my display tank counting my sump and refugium. I try to do a 10 gallon change about ever five days... That would be just under a 10% change, but I do slack off when I am just too lazy.... Larger changes, like 20 or 30% at a time do I fell carry a higher risk of a partial change "shock" to the tank if something is amiss in doing the change.......... Good Luck and I hope this issue works it self out soon....... Being new to all of this is sometimes overwhelming..........

 

[spiderwoman]

Also the pH should match...
I'm just saying that focusing too much on something that is so unlikely the culprit is waste of your time. I probably would have that much time in my hands.