Here we go again: MIs, Take III

[Samw]

Originally Posted by Aquattro

The other guy here that got two had them eating everything in 2 days, fed multiple times per day. They lasted a week. He says he has strong flow and doesn't drop it at night, but woke up to 2 dead fish one morning.
Based on that, I'm going to wait a while before I relax a bit

Again, died overnight. Both at the same time. DO level is always at its lowest at night when lights out after several hours. As I said before, strong flow does not equal high DO. This has been measured before in Eric's paper and also I had strong flow at the surface of my tank which didn't really increase DO. Obviously, I don't know the setup and am just speculating, but the only way to know for sure what the DO levels are from 2am-6am is with a DO monitor/meter which almost no one uses. The sudden death overnight of both animals is a clue. Why always at night? If diet was an issue, the fish would waste away slowly. We've all seen what it looks like when a fish dies from malnutrition.

DO levels fluctuate wildly from day to day, night to night. But the lowest levels are always at night after lights out for several hours and the levels each night are different. I've had my levels go from 125% saturation during the day to something like 35% at night even with skimmer on. Some nights I get 40%. This was 10 years ago. Nowadays, I think I'm getting closer to 80% at night since I have no algae and deploy a UV sterilizer. There are countless things that affect DO but very few aquarists know what their lowest DO levels are at night. In most cases it doesn't matter because many big systems have enough DO for almost all of the fishes out there. Most marine fishes don't need a lot of DO. I think clownfishes only need 18% DO. I read that just a while ago.

[Aquattro]

Originally Posted by Samw

Again, died overnight. Both at the same time. DO level is always at its lowest at night when lights out after several hours. As I said before, strong flow does not equal high DO. Obviously, I don't know the setup and am just speculating, but the only way to know for sure what the DO levels are from 2am-6am is with a DO monitor/meter which almost no one uses. The sudden death overnight of both animals is a clue. Why always at night? DO levels fluctuate wildly from day to day, night to night. But the lowest levels are always at night after lights out for several hours and the levels each night are different. I've had my levels go from 125% saturation during the day to something like 35% at night even with skimmer on. Some nights I get 40%. Nowadays, I think I'm getting closer to 80% at night since I have no algae and deploy a UV sterilizer. There are countless things that affect DO.

Ya, I don't know the system either. I do know he has a lot less algae, but a lot more coral. And his idea of strong flow might not be mine. Currently my bulbs are covered in salt from splashing, and they're a foot off the water. My flow heavily breaks the surface 24/7. Without a DO meter tho, no real way to tell what happens over night.

[Aquattro]

I recall now that he doses H2O2, which reduces the amount of DO in solution, so maybe significant?

[gregzz4]

Originally Posted by Aquattro

I recall now that he doses H2O2, which reduces the amount of DO in solution, so maybe significant?

Could be a big factor
So you know there's a home for one here, right ? Just in case you need to make a trip to J&L ...

Just kidding
If I really wanted one I could go local

[Aquattro]

Originally Posted by gregzz4

Could be a big factor
So you know there's a home for one here, right ? Just in case you need to make a trip to J&L ...

Keep in mind these things have a recommended tank size of 200g I wouldn't add one to a 75g.

[gregzz4]

Originally Posted by Aquattro

I wouldn't add one to a 75g.

Me either. I have enough challenges as it is.

[daplatapus]

IF stuck having to choose which one to give away, my thoughts would always be the biggest and strongest. The one with the most chance of surviving somewhere else.

[Bblinks]

Originally Posted by gregzz4

Me either. I have enough challenges as it is.

JL has some but don't try to quarantine it, it will just die....

[Bblinks]

Originally Posted by Aquattro

Ya, I don't know the system either. I do know he has a lot less algae, but a lot more coral. And his idea of strong flow might not be mine. Currently my bulbs are covered in salt from splashing, and they're a foot off the water. My flow heavily breaks the surface 24/7. Without a DO meter tho, no real way to tell what happens over night.

It would be really interesting to see what the actual DO is reading. I think we should get canreef to sponsor one.... I mean if indeed this is the case that caused a pair of well fed fish into their untimely demise then we might be onto something here. This could potentially save a lot of heartache for a lot of us in this hobby.

Sam, you think you will be able to get your hands on one of them meters?

[Samw]

Originally Posted by Bblinks

It would be really interesting to see what the actual DO is reading. I think we should get canreef to sponsor one.... I mean if indeed this is the case that caused a pair of well fed fish into their untimely demise then we might be onto something here. This could potentially save a lot of heartache for a lot of us in this hobby.

Sam, you think you will be able to get your hands on one of them meters?

Meters can be rented from Hoskins Lab I think. A monitor that does 24/7 charting would be more useful than a meter because the data can be logged and one can go back to look at the levels from the logs when a fish dies unexpectedly at night. Those go for $2,000 though so not many people will own those.

Below is a chart of what I think is a typical a tank. The night bottom value might look low but that is probably typical for an aerated tank. I have no doubt that anyone running a skimmer in their system has enough DO. For those with tanks that are not aerated properly to begin with (using only powerheads or hang on back filters for example), the Idol could be fine for months but over time as algae grew or had a bloom, or the bioload increased, or there was lots of uneatened food one day causing decay and bacteria bloom, or summer came and the temp went up; then one night for whatever the reason, the DO drops just past the point needed for this particular fish and while it was fine for months, it unexpectedly dies (while everything else in the tank was ok). For tanks that have proper aeration (like a skimmer), DO wouldn't be an issue. The problem then is only turning it off and forgetting to turn it back on or turning off the return pump one night.

http://www.advancedaquarist.com/2006/10/review




If a tank has lots of algae, expect the range to be higher. Algae produces O2 during the day and consumes it at night. My results support this. When I had lots of algae, my DO range was large 50%-125%. When I had no algae, my DO range was small 80%-100%.

In this graph below (I think measurements from the Adriatic Sea), the spikes are due to algae growing near the sensor before they fixed it.

http://buoy.mbss.org/portal/index.ph...mid=58&lang=en