"Old Tank syndrome" and sandbed collapse

[TomD]

I would like to here the opinions of some of you more experienced reefers on old tank syndrome.

Has anybody here experienced this? From what I have read, it seems a major factor is accumulation of detritus in the sand bed and LR that eventually build up to toxic levels. I am sure it gets much more complicated than this...

I know some people here have had their tanks going 8+ years. Have any of you changed out a portion of your sand bed? Is this only a concern with DSB or can this also occur with a shallow bed?

I have also read about natural disturbances on the reefs and that some people think it is good to carefully disturb their tank after a while.

If a tank is properly maintained and has good nutrient export, is there no reason to think about this, or does it happen to well maintained tanks as well?

 

[pvh]

Good questions...I'm curious as well.

 

[RayD]

How about this thought. I added a Tiger Tail Cucumber to the reef. I've read great things about this animal and it's the opinion of several expert reerfers that these are one of the best animals to have in your reef.

They live in the sandbed and spend all their time cleaning, cleaning, and cleaning.

A friend that was breaking down his reef gave me his. I rarely see mine but ocassionally at night.

Aquarium Gallery carried them regularly and I'm thinking they might contribute to the prevention of "old tank syndrome" to some degree anyway.

 

[naturebatslast]

Talking with Terry Siegal about this and a consensus was that it does happen to well established tanks and could possibly be allievated with a massive water change (greater than 50%).

 

[TomD]

Talking with Terry Siegal about this and a consensus was that it does happen to well established tanks and could possibly be allievated with a massive water change (greater than 50%).

When you see symptoms or just after so long?

 

[Yaktop]

old age debate and in RC debated often and just isnt a consensus except most believe the DSB is the best method. other have done the RSB (remote sand bed) who can simply change out all the sand every few years but that is very uncommon in comparison.

 

[JohnK]

FWIW, there is a great discussion of this topic in "The Reef Aquarium vol 3". (yes, I've been plugging that book constantly, I just like it a lot)

 

[TomD]

old age debate and in RC debated often and just isnt a consensus except most believe the DSB is the best method. other have done the RSB (remote sand bed) who can simply change out all the sand every few years but that is very uncommon in comparison.

I know the debate but I want to know if you can also have this happen if you are running a less than DSB.

Or does this only "usually" happen to an improperly maintaned DSB?

Or is it more than just the sandbed...

 

[JohnK]

FWIW, the book ref I mentioned above has seperate sections on different sandbed methodologies (some of which have completly different approaches to things like stiring vs not stirring sand) and "old tank syndrome". A lot of good related reading IMO.

I haven't been following the RC debates exct, but IIRC the idea/term "old tank syndrome" has been around since long before the great DSB debate even started.

Again, IIRC, old tank syndrome is a sort of generic term for tanks that do well then go into a decline for unknown reasons after a number of years. There is speculation about numerous possible causes, DSB related problems being very reasonable possibilities among other things.

I'm guessing that old tank syndrome idea/term got linked to the DSB debates because of the obvious hypothisis that they are interrelated.

The thing I question is if this might confuse things/terms because "old tank syndrome" may be a term that's more like "RTN" where it's really referring to a symptom of one or more, not fully understood problem(s)/factor(s). The same might even be said of the DSB crashing debate.

There may be 5 ways a tank can go into old tank syndrome, and a few ways a sandbed could crash, but it might be oversimpified by assuming that,
for ex;

-A tank that's been healthy for a few yrs clearly begins to decline for no known reason > must be old tank syndrome > must be a sand bed problem.-

Not trying to dismiss what anyone is saying or asking in any way, just suggesting that at least in my understanding, this is a very complex set of issues/questions and the symptoms and specific causes may vary and or overlap.

Great topic,

 

[TomD]

Great response John! That is why I asked about all of this. I don't think it is as simple as keeping a clean sandbed.

 

[JohnK]

As I've taken it in, it's a fascinating intersection of different factors.

Also, I skimmed through a magizine at B+N bookstore the other day and there were 2 or 3 pretty interesting articles relating to sandbed methods. I don't remember which mag it was, but there are only about 2 aquarist magizines to choose from.

 

[naturebatslast]

When you see symptoms or just after so long?

It was suggested that yearly 50% WC's should occur in an attempt to prevent OTS. In addition, he also skimmer very aggressively with 2 huge skimmers and ran a big carbon/phosban reactor.

 

[TomD]

Really? You know what, it seems like a good idea to me. As long as you match parameters I can't see any harm?

Is anybody doing this or anything similar?

 

[JeremyR]

Maybe instead of doing yearly water changes, if people just did their regular normal water changes instead of doing everything possible to avoid water changes, it wouldn't even ever come up...

Btw, the best thing about TRAIII is the page with my name on it. Hehehe.

 

[TomD]

Maybe instead of doing yearly water changes, if people just did their regular normal water changes instead of doing everything possible to avoid water changes, it wouldn't even ever come up...

That is back to my original question (one of them) Will a properly maintaned tank have a chance of getting "old tank syndrome?"

Matt says he has heard yes.

Jeremy, in all the years you have been doing this, have you ever experienced these kinds of problems?

 

[JeremyR]

Not really.. but we have always been frequent water changers, especially if anything looks "off". We've had bare bottom, DSB, middle-deepSB, shallowSB, and I can't say that any of them ran any differently or had results better than another. That doesn't mean there has never been a problem.. we've certainly had various algaes in various tanks, but never something I would call OTS or that would cause me to want to rip a tank down & start over.

 

[TomD]

Good enough. My feeling on this is that if I have a good cleaning crew, good flow, good nutrient export, don't overfeed..on and on, that this can never happen.

What Tery Siegal said is interesting. How/why does this happen to a tank that is properly maintaned?

How do you even determine that your tank is going through something like this? A rise in nitrates/amonia so that your tank does not break down nutrients anymore?

 

[Aquaman_68]

Not really.. but we have always been frequent water changers, especially if anything looks "off". We've had bare bottom, DSB, middle-deepSB, shallowSB, and I can't say that any of them ran any differently or had results better than another. That doesn't mean there has never been a problem.. we've certainly had various algaes in various tanks, but never something I would call OTS or that would cause me to want to rip a tank down & start over.

I want to rip mine down & start over monthly...I think the subject at hand exists in my opinion Tom....I don't think large water changes help. All they do is help to extract high levels of organics that have leached out of the rock. That method of 50% or greater.....Maybe every other day for a couple weeks that might work.....Problem there is...It will stress the bio area out very much......Jeremy...your reef tanks don't have much in the live rock area...The live rock also acts like a sponge...problem is it can leach out as it can suck up & over time can be totally saturated...JMO & I'm sure I will be debated....But I couldn't resist!!!

 

[KAS2]

frequent small water changes are better

Maybe instead of doing yearly water changes, if people just did their regular normal water changes instead of doing everything possible to avoid water changes, it wouldn't even ever come up...

I agree with Jeremy. There's a common misconception that major water changes are more efficient than multiple minor ones. Besides the fact that a major change jolts the ecosystem, the math shows that multiple small changes also do the trick.

If you change X of the water (X from 0 to 1), you have to do it 1/X times to replace the entire volume of water. So, 50% would be done twice, 20% five times, 10% ten times, etc. If you look instead at the "old" water remaining after each change, two 50% changes leaves 1/2 squared, five 20% changes leaves 4/5 to the fifth power, ten 10% changes leaves 9/10 to the tenth power.

Now try this with Excel:

<column2>=1-(<column1>/100)
<column3>=POWER(<column2>,1/(1-<column2>))

column1 = % water change
column2 = fraction of old water left after 1 change
column3 = fraction of old water left after 100% volume change

50 0.5 0.250000 <-- 2 50% changes
40 0.6 0.278855
30 0.7 0.304551
20 0.8 0.327680 <-- 5 20% changes
10 0.9 0.348678
5 0.95 0.358486
1 0.99 0.366032
0.1 0.999 0.367695
0.01 0.9999 0.367861
0.001 0.99999 0.367878 <-- 100000 "drop-for-drop" changes

BTW, this converges to 1/e = 1/2.718281828 = 0.367879
Ain't math wonderful?

So, even having a zillion nano changes leaves you with only 50% more of the original water than two 50% changes. All in all, I think this shows that frequent small changes are the way to go.

Whether this will fix Old Tank Syndrome is still an open question.

 

[TomD]

I want to rip mine down & start over monthly...I think the subject at hand exists in my opinion Tom....I don't think large water changes help. All they do is help to extract high levels of organics that have leached out of the rock. That method of 50% or greater.....Maybe every other day for a couple weeks that might work.....Problem there is...It will stress the bio area out very much......Jeremy...your reef tanks don't have much in the live rock area...The live rock also acts like a sponge...problem is it can leach out as it can suck up & over time can be totally saturated...JMO & I'm sure I will be debated....But I couldn't resist!!!

Good point with the LR. I do think that having too much to the point of low flow through will speed this problem up. I keep a real open rock structure for that reason.

Brian, how do you experience this with your tank when you say it does exist?