Common Misconceptions In the Hobby

[JPMagyar]

Truce on temperature variation.

Truce on temperature variation.

Alright, I promise to leave this particular example alone after this last response . . .



You have stated, without modification or clarification, and in a manner which would imply applicability to all currently maintained reef aquariums.

When people keep their tanks cooler or more stable with the false notion that they're increasing the margin of error they're doing the exact opposite.

The excessively broad nature of your statement makes it inherently false. No scientist would make such a sweeping argument without years of evidence and trial studies to prove such a point. Furthermore, even if one were to accept the principal that temperature variation in tanks can improve survivability that does not imply that the goals of an aquarist will necessarily be enhanced. Survivability is but one aspect of most aquarists needs or desires. Biodiversity, coloration, polyp extension, growth rate, these too are on the minds of many tank owners and are in no way addressed by the research of marine biologists in situ. I recognize the statement does not directly address such issues, but the implication is temperature variability in tanks is superior to stability which has much the same connotation. Now having said all that I will admit to a certain level of devils advocacy here.

You may be shocked to know that my own reef swings from between 77.8 to as high as 83.4 degrees Fahrenheit on a daily basis during the summer months. I do not use a chiller and rely on my large basement sump to act as a heat sink during the day. So as you can see I have no anxiety over temperatures nor do I disagree that RCers benefit from a discussion on temperature variability, but what I do feel strongly about is sweeping generalizations made in a manner which implies absolute universal truth. Whether intentional or not I can assure you that many people reading your statement, over which I am arguing, will take that as gospel for all tanks in existence without ever researching the data behind the conclusion, and that is the travesty of the internet. The true irony is my argument is easily ended with the simplest of rewrites:

Marine biologists studying certain wild corals have found that those which get frequent and large temperature swings have a better chance of surviving short term heat spikes. The average aquarist may find their tank will benefit from allowing greater temperature variability, and perhaps need not be so anxious over temperatures as previously thought.

Now that - my dear Watson - is a fact!

I have very much enjoyed the discussion, and am thrilled at all the new reading I have as a result of researching this issue so for all of that I say "Thank-you". I only hope you understand the nature of my discourse, and will not hold that against my person.

Joe

 

[greenbean36191]

You're right that science can't ever "know" anything. The best we can do is look at the evidence, make a general statement and try to disprove it and come up with something better. The statement I made goes back to a principle that has been around for probably more than 100 years in terrestrial and aquatic environments. It's virtually universal there and it's so accepted that it's something you learn about literally in freshman ecology. Does that mean it's been tested on everything, or that it's even universal in everything that has been tested? No, but for the sake of general discussion it's true. People have been testing the same thing in marine habitats since at least the early 70's and so far it seems pretty much universal there too. Just off the top of my head I know it's been directly tested in Montastrea, Montipora, Pocillopora, some fish, and some inverts including "margarita" snails. There are further in situ observations supporting that it occurs in Porites, Acropora, and Fungia, plus the anecdotal evidence of hobbyists. Have we tested everything? Of course not, so yes, it's an assumption based on a small sample. However, so far there's no evidence to suggest that it doesn't hold true for most cases and we have no reason to believe that marine environments are unique in that regard.

Given absolute statements like "temperature swings should be kept to a minimum because they're stressful to the corals/ fish," which have virtually no scientific basis, I think for the sake of discussion in a public forum it's fair to refute them using equally absolute statements based on the body of evidence. Is it acceptable in court or in a scientific paper? Of course not. I agree that your statement is more tempered and leaves out most of the assumptions of my statement, but I would still change it slightly.

Marine biologists studying certain corals in the wild and in controlled lab conditions have found that those which get frequent and large temperature swings have a better chance of surviving elevated temperatures lasting from hours to months. They also withstand higher temperatures before heat stress responses are observed. The average aquarist may find their tank will benefit from allowing greater temperature variability, and perhaps need not be so anxious over temperatures as previously thought.

Biodiversity, coloration, polyp extension, growth rate, these too are on the minds of many tank owners and are in no way addressed by the research of marine biologists in situ.

Like I mentioned, I just copied and pasted the list of articles from another thread where I was having a similar discussion, so I'm not sure what if any of these issues are addressed in them. I actually don't have access to most of them ATM since I'm on the road. Biodiversity and growth rate have both been addressed, though the impacts on either aren't very clear. You would expect growth to be slowed slightly with variation and increased with increasing temperature. There was at least one study I can think of that showed that, while another showed the exact opposite result. Biodiversity is almost always highest in areas with higher and more variable temperatures, but that correlation doesn't imply causation. Disturbance frequency due to things like hurricanes also correlates well with many of those areas.

 

[Aquarist007]

IMHO--you have in a round about way given support to greenbeans original statement.

"When people keep their tanks cooler or more stable with the false notion that they're increasing the margin of error they're doing the exact opposite."

by your statement:
"Marine biologists studying certain wild corals have found that those which get frequent and large temperature swings have a better chance of surviving short term heat spikes. The average aquarist may find their tank will benefit from allowing greater temperature variability, and perhaps need not be so anxious over temperatures as previously thought."

Now that - my dear Watson - is a fact!

and supported it anecdotably from your own experience.

The power of internet sites like Reef Central is that it provides a medium for experinced reefers to give their points of view based on what worked for them--what didn't work for them.

That is basically what I quote in my avitar----experince is the best teacher.

Reef central is also very fortunate to have reef hobbyists//marine biologists contributing to threads. And equally fortunate to have had a great scientest like Randy Holmes----and hobbyists who have mentored under him available to less experinece hobbyists like myself and others.

I give alot of credibility to these guys like greenbean ect and allow them to influence my thinking to the point of taking action.
Up to this point I feel I have profited by it---much more then reading article after article in science journals---when they get so complex in biochemistry I tend to nod off

I like this hobby because it is hands on--it requires science skills--and I can get a quick practical answer to my questions on Reef Central.

You are correct in one of your original posts---this was a great thread at the start-------but as I notice---I am one of the few inexperieced reefers left supporting it---and have to admit being turned off also--by a verbal berage off quoting one scientest article after another in order to win an argument.
In a discusion there are no winners or losers--except the readers who profit from a broader perspective on the issues.

You mention you are a devils advocate---in cyber language there is another word for it--and by no means am I being accusatory here---but it is called tr******.

Greenbean----I still am in awe of your expertise and the help you give us reefers----------buy don't give into your principles here--
and continue filling this thread up with citations from scientists works-----I still believe in what you--the experienced reefer posts.

 

[JPMagyar]

<a href=showthread.php?s=&postid=11227654#post11227654 target=_blank>Originally posted</a> by greenbean36191
Given absolute statements like "temperature swings should be kept to a minimum because they're stressful to the corals/ fish," which have virtually no scientific basis, I think for the sake of discussion in a public forum it's fair to refute them using equally absolute statements based on the body of evidence.

Touche and fair enough

<a href=showthread.php?s=&postid=11227688#post11227688 target=_blank>Originally posted</a> by capn_hylinur

You mention you are a devils advocate---in cyber language there is another word for it--and by no means am I being accusatory here---but it is called tr******.

TReehugger
Trashtalker
TrulyNiceGuy

I am the first to admit I want to learn everyday so I hope you'll PM with the answer

<a href=showthread.php?s=&postid=11227168#post11227168 target=_blank>Originally posted</a> by JPMagyar


1) This is what I dislike about RC, people can say anything and it passes down as "knowledge".

2) to make sweeping generalizations as to the need to increase the average accepted temperature without serious discussion and evidence is to me a disservice to the community at large, and I find that this particular issue is but one of many that were mentioned here within under the simplest of pretexts using little or no evidentiary support.

3) The tradition of opening debate and challenging accepted notions is noble and ancient, but to jump to conclusions and state them in a factual manner trivializes the best that RC has to offer and lies at the heart of my complaint.

4) but what I do feel strongly about is sweeping generalizations made in a manner which implies absolute universal truth

And that I promise is my last addition to this wonderful body of discourse . . . you may all breathe a sigh of relief


Joe

 

[Aquarist007]

TReehugger
Trashtalker
TrulyNiceGuy

I am the first to admit I want to learn everyday so I hope you'll PM with the answer

Joe, I do not feel remotely qualified to continue to debate with someone as experinced as you and I definetly want to keep my posting friendly and postive on Reef Escape as I have strived for in the past.
So------choice #3 would be a personally prefered way of ending this series of posts---
TrulyNiceGuy works for me and I hope it works for you

 

[Aquarist007]

Wow--just when I was starting to be "misconception free" after being in RC quarantine for 8 months or so.
I started a thread basically to see how I could cut my energy costs through lighting and filtration(return pumps)

I was blown away by this thread:

http://www.reefcentral.com/forums/s...me a large return pump is needed&pagenumber=1

Since my onset in reef keeping I was read, been told, etc that it is diserable to have a tank turn over of 20- 40 times.
I really don't understand how a return flow to match your skimmer is going to be adventagous to corals etc in your tank.

--or are people considering the tank turn over as total flow within your tank.

I started out with a discussion of an alternative to my mag3600 with 7 feet of head and plumbing was giving me a gph of about 1800--2000. That mag3600 is a bit of an energy hog with 350 watts per hour.
Here is the thread I started

http://www.reefcentral.com/forums/showthread.php?s=&threadid=1255315

 

[hkyeo72]

I think the most important thing that one should notice is how well is the coral and fish doing in the tank, even if there is high nitrates reading or kh or ph. I have been keeping reef for five years and till' now I still have problem with nitrates (20-30) but my corals seem doing well and they are climate to the changes to survive in close system.

 

[Paul B]

I think turnover rate is confusing. As long as you have good circulation, you will be fine. I have dove enough times to know that there is a nice current on most reefs. Some of it is so strong like in Cozumel that you can't swim against it. The fish look like they are struggling but they are used to it and can rest behind a rock if they like. I turn off the pumps to feed.
I also believe that at least one pump should be semi aimed at the surface as this is where oxygen transfer and CO2 is eliminated.
Paul

 

[Philwd]

Turnover refers to every pump you have running. Returns+PH+CL. There is more to it than just overall turnover. The flow needs to be able to eliminate dead spots. My total turn is at any one time 45-50X. It would be higher but I have my vortechs running antisync 1 on 1 off.

I think the sweet spot for a return pump is 5-10X the sump volume. But I also run one overflow right into the skimmer to get direct raw surface skimmed water into the skimmer. So I actually run a little higher than 10X to make sure the skimmer is fed enough water. If I ran the skimmer the more traditional way in the sump then I would cut back on the return flow a bit.

 

[Aquarist007]

if the sweet spot is 5-10x's that would leave a tank circulation as 25-30 times. Would my tank(and inhabitants ) be able to take that kind of flow?

 

[Philwd]

The assumption is you point your returns towards your corals. Whether you do that or not I guess determines whether you should count that flow as turnover. Mine are pointed into the vortech's flow to create lots of random vortices.

 

[LobsterOfJustice]

<a href=showthread.php?s=&postid=11235995#post11235995 target=_blank>Originally posted</a> by capn_hylinur
if the sweet spot is 5-10x's that would leave a tank circulation as 25-30 times. Would my tank(and inhabitants ) be able to take that kind of flow?

I'm not really sure what you are saying here. Lets say you have a 75g tank and a 30g sump. If you run 5-10x sump turnover you want a return pump that is 375-750 gph. Throw a few powerheads or a closed loop on the main tank to bump this flow up to 20x-40x or whatever overall circulation you desire.

 

[Aquarist007]

<a href=showthread.php?s=&postid=11236226#post11236226 target=_blank>Originally posted</a> by LobsterOfJustice
I'm not really sure what you are saying here. Lets say you have a 75g tank and a 30g sump. If you run 5-10x sump turnover you want a return pump that is 375-750 gph. Throw a few powerheads or a closed loop on the main tank to bump this flow up to 20x-40x or whatever overall circulation you desire.

I was just asking if a 120 gal could take that much flow within it without blowing everything around and annoying corals, creating sand storms etc etc

 

[LobsterOfJustice]

Well it isnt a set amount. 5-10 through the sump is technically all that is "necessary" and you add powerheads to reach whatever other amount you want. 20x-40x is very common. You just have to not point the flow at corals (particularly LPS) or the sand.

 

[Aquarist007]

<a href=showthread.php?s=&postid=11239743#post11239743 target=_blank>Originally posted</a> by LobsterOfJustice
Well it isnt a set amount. 5-10 through the sump is technically all that is "necessary" and you add powerheads to reach whatever other amount you want. 20x-40x is very common. You just have to not point the flow at corals (particularly LPS) or the sand.

LoJ--can't say it enough how much I appreciate your help--

(from another post)

I have the original pump that the mag3600 replaced:
http://www.coralreefsupply.com/inde...tail&detail=130

I was going to create an external closed loop with it--but have hesitated due to safety considerations with that kind of set up.

Does any one have the head pressure specs on this pump--its not listed in the RC calculator?

I am wondering if it would give enough flow through the sump. If is then I can spend some money on updating the pw's and try to sell the mag3600

 

[LobsterOfJustice]

I've got another misconception that I would like to address:
Dosing phytoplankton is a way to mimic the natural reef. The food chain is based on phytoplankton.

I do not believe this is true.

Let me just say that I am a freshman in college, majoring in marine biology. I have taken two oceanography courses, and that is where my information is coming from.

Tropical reefs are largely devoid of phytoplankton. Phytoplankton needs light and nutrients to grow. Nutrients come from upwelling, which is not common in tropical reef areas due to a strong thermocline. Below is a picture of "ocean color", which is a way of measuring phytoplankton density by measuring chlorophyll concentrations. Notice that most of the coastal productivity occurs on the eastern edge of the ocean basin (the western edge of the continent)

This picture is the distribution of coral reefs:

Hard coral reefs, on the other hand, are found on the western edge of the ocean basins, or the eastern edge of the continent. The coriolis effect causes the water in oceans to rotate. This "gyre" is pushed west by the rotation of the earth, which is called western intensification. This leads to stronger warmer currents on the western edge of ocean basins (transporting water from the tropics to the poles). This warm water current on the eastern side of continents is one reason why corals are found in these areas.

Warm surface water over cool deep water forms a thermocline, or a rapid change in temperature in these areas. This acts as a "cap", preventing upwelling from supplying these areas with nutrients which phytoplankton need to grow. Deep water is free to upwell on the eastern side of ocean basins because there is no thermocline. This is why there is phytoplankton productivity there.

We all think of crystal clear water in tropical coral reefs. Guess why that water is so clear. Because there is no phytoplankton in it. Again, because tropical reef areas are nutrient poor.

 

[Aquarist007]

I think we discussed this earlier in the thread
most lps and soft corals feed on zooplankton
zooplankton feed on phytoplankton
if raising predominately lps and softies then dose with cyclopeeze and save the phyto for a refugium.

 

[LobsterOfJustice]

Honestly, I have yet to see zooplankton in any saltwater tank, ever. There are plenty of benthic critters like amphipods and copepods, but no actual zooplankton. It would be imediately eaten by most of the fish, or filtered out. These "pods" in our tanks eat algae and detritus, not phyto.

 

[Paul B]

Actually, the young of copepods and amphopods are also zooplankton, any small animal that drifts on currents rather than swim on their own is zooplankton.
You are correct that tropical reefs are practically devoid of zooplankton and you won't find large concentrations of it on your chart. But the young of almost every living animal on a reef including inverts was at one time zooplankton. A typical averaged sized fish lays thousands to millions of eggs which all turn out to be zooplankton. Corals expel millions more.
There are vastly less fish in tropical waters than in temperate for the reasons you stated but there is still a large enough number of zooplankton to feed the reefs. If it were not for zooplankton, there would be no need for the feeding tentacles on most corals, sea fans, non photosynthetic gorgonians or filter feeding animals like clams and anemone crabs.
As to feeding corals with a substitute plankton, that is up for debate as many corals can live on light alone.
Paul

 

[LobsterOfJustice]

Agreed paul.

But it seems that feeding phytoplankton would not promote fish, coral, or other invert spawning. So I would say that instead of dosing phyto, maybe having a mated pair of gobies/clowns, a few cleaner shrimp, or having a healthy population of other spawning critters such as stomatella, would be a better way of replicating nature and feeding our corals.

Perhaps what I should have said before is "I have yet to see a stable zooplankton population." All these events result in temporary surges of zooplankton availability, not self-sustaining populations (let alone ones which would require phytoplankton to survive and thrive).