People with DO meters

[tatuvaaj]

Hello!

Could some one with a DO meter tell what kind of DO levels they measure from their reef aquarium both during night and day? Also, if you could report your salinity, temperature and sand depth I would be most thankful !

TIA !

[Randy Holmes-Farley]

I'm interested too, although I've never taken such measurements.

Do you have any data of your own?

[tatuvaaj]

Randy,

No, I don't have a DO meter yet. I've been thinking about buying one for a long time. If the data people report (hopefully!) looks interesting enough I'll buy one

[Boomer]

tatu

I don't have one either, but a proper O2 meter is 100's of dollars and are corrected for Salinity and atmospheric pressure. You may want to try the HACH Digital Titrator for $ 140. Test O2 down to 0.02 mg / l. I have one . No, I never ran the test you want You will be suprised what you get though. Many people don't have as much as they think

[tatuvaaj]

Originally posted by Boomer
I don't have one either, but a proper O2 meter is 100's of dollars and are corrected for Salinity and atmospheric pressure. You may want to try the HACH Digital Titrator for $ 140. Test O2 down to 0.02 mg / l. I have one .

Thanks for the tip! That sounds reasonable.

No, I never ran the test you want You will be suprised what you get though. Many people don't have as much as they think

Yes, that's what I'm afraid of For example, Ascidians are known to lower their pumping rates when oxygen levels drop enough.

[Boomer]

Ascidians

One of my favorite groups Got a coupld of books on them

[Randy Holmes-Farley]

I'll check and see if I can find one to try. This sounds interesting.

[Habib]

Tatu,

We have a WTW O2 meter + probe.

Can't remember what we paid.

IME an O2 measurement is not so interesting unless one want's to experiment.

Addition of food and use of organic based calcium supplements will consume oxygen.

[Randy Holmes-Farley]

One thing I'd like to test is how well O2 remains when I have a power failure and I'm left with just backup powerheads on a UPS.

[rsman]

try the HACH Digital Titrator for $ 140 I have that at probibly boomers previous recomendation, and I borrowed a DO meter i played around with them on a number of tanks just for kicks

its cool, but I didnt have a reference point for my reef, I use it on my cultures instead

the power loss issue was a serious concern when I was playing the backup powerhead will work SOOO much better if you hook up a venturi to it, you can hook it up so that in normal operation its submerged, but when the waterlevel lowers a tad when the return is cut the air hose sticks out of the water. the best results I found was a battery powered air pump hooked up to a small airlift with a 90 elbo. though you might need more than 1 the cost and runtime is offset by the cost of a UPS and powerhead.

[Randy Holmes-Farley]

you can hook it up so that in normal operation its submerged, but when the waterlevel lowers a tad when the return is cut the air hose sticks out of the water.

Nice suggestion. Thanks.

[rsman]

ooh yea I forgot put an airline T on the end. itll keep that mini whirlpool thing down and keep things from blocking the input.

[Randy Holmes-Farley]

Thanks.

[Habib]

Originally posted by Randy Holmes-Farley
One thing I'd like to test is how well O2 remains when I have a power failure and I'm left with just backup powerheads on a UPS.

Sounds like a nice experiment.

I have a feeling that water movement might be far more important than the O2 concentration in the bulk of the water.

If there is not enough watermovement or not at all then the boundary layer around the corals will become (much) thicker and reduce the oxygen uptake rate and removal of excreted substances.

[Boomer]

Hab

You're back, missed you

[Bryan]

http://www.canreef.com/phpBB2/viewtopic.php?t=9942

[tatuvaaj]

Bryan,

Thanks a lot for the link! Very interesting information.

I'm somewhat surprised to see such a huge drop in O2 concentration during night, a drop to 50% from the highest value can very well have impact on at least some animals' health.

It seems like his tank doesn't have the best possible aeration so it would be interesting to see if the photosynthesis has such a huge impact on DO in tanks with a overflow and a skimmer.

[tatuvaaj]

Boomer et. al,

What do you think about the American Marine Pinpoint Oxygen Monitor ?

[beaslbob]

Please don't tell my wife there is actually a do meter.

[Boomer]

Tatu

I have some serious issues with it. First, nowhere on their website is there any mention for seawater. A DO probe needs to be corrected for seawater or at least have a table for the correction, like YSI has on there less expensive meter. Second, I see nothing on correction for barometric pressure. Some of the cheaper meters have one for altitude ( a cheap cheat method) but altitude does not always mean an equal barometric pressure across the board as you go up or down in elevation. Barometric pressure is always changing, a home barometer will show you that and it is that value what should be used as the dial in on a good O2 meter, not altitude. Some good inexpensive meters have all the corrections on a table or plotted graph but I see no mention of either for this meter.

[Boomer]

Bob, what is your phone number, I need to talk to your wife I have one all picked out for her, it is only grand or so, with all the Acc Tell the wife to come to the PC for a lookzee. And it is waterproof

[tatuvaaj]

Boomer,

Thanks again!

I might be completely lost here but wouldn't all those variables affect the saturation reading only and not the actual mg/l reading?

I think I'll get the HACH kit as you recommended. Anyone know a good online shop in EU for HACH products?

[Boomer]

I might be completely lost here but wouldn't all those variables affect the saturation reading only and not the actual mg/l reading?

No, the meters even do saturation in %. At a measured salinity, temp and barometric pressure you can mathematically calculate saturation, just as the meter
does

S´= S x P´/ 29.92 - ( C X F)

To make it easier for you for seawater the value from the calculator below is..... x mg / O2 = 100% saturation


http://www.aquanic.org/images/tools/oxygen.htm

I have two more but they are for FW

[Habib]

Randy:

This might be an interesting and useful article for the experiment you are mentioning.

http://www.biol.sc.edu/~helmuthlab/c...aEdmunds99.pdf

[Boomer]

Hab, nice piece