Re: NANFA-- The dissolved oxygen thang

Travis Haas (travis.c.haas_at_lawrence.edu)
Sat, 18 Jan 2003 19:06:03 -0600

Todd, thanks for sharing the great story. It was definitely worth
hearing. Sorry you had to lose sleep to share it, though :)

Travis Haas
Appleton, WI


Todd Crail wrote:
>
> So I'm laying trying to remember the name of an exotic invasive plant
> (teasel) at 5 in the morning and then I'm all awake. I figured, well, I
> might as well get Travis the info he was asking for heh. Maybe even get Jim
> his testing for the Trip Report Application :) Then hopefully I can catch
> a nap before I have to "get up" for the day.
>
> I don't think this segment of information is going to be appropriate for AC,
> however, it is an excellent base for a study that could be done with native
> tanks, that would be very useful information. Perhaps this information I'm
> going to type right now will inspire others to collect the data. I dunno.
> Here's the anecdote and what I learned from it.
>
> My marine fish system consisted of 28, 30 gallon long tanks that were
> drilled with bulkheads. They all shared a common 100 gallon sump and were
> circulated by a 3/4 hp pool pump. Originally, there was a 200 gallon
> acrylic reservoir attached, and an additional 15' on the line back from the
> pump. I felt the plumbing was inefficient in design, the return rate too
> slow for reef dwelling fish, and this feeling cost me a lot a lot a lot of
> money. ;) I picked up Escobal's book "Aquatic Systems Engineering" and I
> thought I was just going to be able to stuff the system with fish when I was
> all done. Aiye Aiye Aiye.
>
> I took out the reservoir (it was ready to bust at any moment anyway) and
> moved the sump into the same area where the system was to take the length
> out of the line. I also purchased a mombo protein skimmer that uses beckett
> pond injectors for it's air source. Pictures of it can be seen at:
>
> http://www.farmertodd.com/ImageIndex/2001/081301/default.htm
>
> They're listed as "SkimmerX". That's a 55 gallon aquarium next to it. It
> was basically a big hoobajoo that looked like I knew what I was doing. If
> I'd trusted my ecology senses and not the "humans can do things better than
> nature" sentiment... I'd prolly be much further along. But live and learn.
>
> So what happened? Well I changed the plumbing to match what an expert said,
> I added the big monster skimmer to inject air and remove dissolved organics
> the second they evolved in the water, the flow was increased by 3 times, to
> the point that it was topping out the bulkhead returns. Time to bring in a
> bunch more fish, eh?
>
> I came back the next morning and half of what I did have was dead. And I'd
> had them in for a bit and they were all very well acclimated. Was it the
> glue? Did someone dump something in my sump? The shipping mortalities were
> all over with, but I have a piscean holocaust going on? Not knowing what
> was going on, I did the next logical thing and ordered another box of fish
> :( When I took nearly all of them to the dumpster the next morning after
> their arrival, I knew something was really goofy.
>
> I moved the few surviving tangs and angelfish, which were breathing in an
> awful manner, into the coral system which was 14, 30 longs on a common sump,
> but had the advantages of a full living system with all sorts of algaes,
> macroalgaes, extra bacteria, etc. Within an hour they were all calm and
> eating. Now what is that all about?
>
> I had other stuff to do, so in an effort to save electricity, I turned off
> the skimmer and went about my way doing other things... Like for a few weeks
> heh. But this was probably the best thing I could do, because it gave me
> time to reflect and try different things out.
>
> One thing I noticed was either the pump was cavitating (creating pockets of
> air inside the chamber) or the line had a hole in it. Somewhere there was
> air coming in, and that would gurgle out from time to time. I was never
> able to locate that hole and I took the danged pump apart like 3 times
> (which was always a job). This wasn't a big problem, so it seemed... But
> later I would observe differently.
>
> Another thing I noticed was on days where it was cooler (it was Sept/Oct)
> and not necessary to have the front and back door open, and the heat was on,
> fish would breathe harder and turn very washed out color. I would switch in
> and out a couple tangs, anthias or angelfish each day to see what would
> happen. Door closed for 24 straight hours, health seemed decreased, but not
> deadly. So one night, I thought... Hey why don't I turn on the skimmer and
> see what happens. My 4 test subjects were good and dead the next morning.
> Skimmer is back off.
>
> It was becoming evident that there was an issue in oxygenation, but I
> couldn't understand why with all the aggitation going on. That's when I
> resigned to spending the $200 wholesale on a digital Dissolved O2 probe.
> What I found was amazing.
>
> So I reved everything all up when I got the probe calibrated. I found that
> the DO2 would *bounce* all over the place. Saturation is at 11 mg/l in
> marine water, a level of 7-9 mg/l is a safe range. In my system, as water
> would pass, I would get 6.0, 3.4, 5.4, 2.1, 5.6, 6.7, 3.5, 4.7 and so on in
> a 15 second interval. It wouldn't sit still. I thought, well something is
> wrong with this probe... So I moved it to the coral system. Locked in real
> nice at 7.4. Wow. Took it over to the freshwater system, right and tidy at
> 6.0. Put it on a system that was curing live rock (huge amounts of organics
> which deplete O2). Ready steady at 4.5 All numbers I would expect to see.
> Now it was time to play...
>
> Something that I noticed by the fish breathing and coloration was that when
> the heating "system" was on, things were much worse. The two blowers for
> the building were at each end of the system. They were nasty cantankerous
> looking things, and they'd melt your contacts right to your eyes if you
> stood in front of them. I added this into the testing.
>
> This was done over the course of a couple days. I should have been
> recording data, but with the variability in numbers, I just threw my hands
> up and wrote down these observations:
>
> Doors open, heating system off, skimmer off... The control. Fairly stable.
> Doors open, heating system on, skimmer off... Less stable.
> Doors closed, heating system off, skimmer off... Less stable.
> Doors closed, heating system off, skimmer on... Much less stable.
> Doors closed, heating system on, skimmer on... Very suppressed and very
> unstable.
> Doors closed, heating system on, skimmer on, photoperiod over (4 hours after
> lights out).... DEADLY. It would rock between 2.0 - 4.0.
>
> Well, there's my answer. Ugh.
>
> I tried it on the coral system and it would suppress in the dark cycle, but
> it seemed the algaes had offered a lot more oxygen to begin with. It didn't
> hurt that this system was on a 14 hour photoperiod either, whereas the fish
> system lights were on when I was there (8 hours). Fun, fun, fun.
>
> I ran my air intakes on the skimmer outside, and that made a huge
> difference. However, being that it was a commercial area and I found a van
> backed up with it's exhaust right over the intake one morning, well, that
> didn't fly. Yikes! Fortunately, I had turned the skimmer off during some
> maintenance and forgot to turn it back on that night. That just about made
> me sick seeing that. I really didn't want to open the door.
>
> However, for the home aquarium, I've found an outside airline to be very
> effective. Well, that is until the danged city goes by spraying for
> mosquitos, which, well, I won't start... At any rate, that's not a fun time
> running around pulling in lines. That's the one downside. However, as
> another case study, one fella in the area who'd spent hours and hours and
> hours online getting advice and opinions and dollars and dollars and dollars
> trying to get his fish to live, all he needed to do was put an airline
> outside. 1/4" airline tube attached to his skimmer air intake out the
> window and his fish were just fine. Man of all the $3.00 solutions, huh?
> :) His house was a new house that was like super energy efficient, and he
> just didn't have enough O2 to mix into his tank when the heating system was
> on, as that recirculates air. He also had a monster skimmer. This has also
> solved a lot of online contact's problems too. Pretty interesting stuff.
>
> So enough about this marine aquaria junk. How can we use this? Well, I'd
> say we'd be able to more saturate our aquariums in the same manner. The
> question is how to do this inexpensively and efficiently? I don't think you
> need to spend $200 on a skimmer for your 20 gal darter tank lol. Now that
> the tank is at home, and well, I'm at home, I'm gonna play with some designs
> I've had in mind. It would be prime to make a hang on the back doodad that
> has an unnoticeable, sleek design and just evolves outside air into a
> chamber. It will be especially interesting to see what effects this has on
> fish coloration at higher temperatures, general health and so on. I'll be
> much better about tracking data, and that would be something worthwhile for
> AC :)
>
> Okay. I think I'm gonna go back to sleep now. :)
> Todd
>
> I hope you know that this will go down on your permenant record.
> http://www.farmertodd.com
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