Weekly Discussion Thread - Tides

[OneDummHikk]

What influences do the tides have on livestock?
And, what are people doing to try to duplicate that in a closed tank? Or, can you even duplicate it in an aquarium?

[TheReefer12]

Tides will help bring die off out of the water onto the beaches. When the waves crash and creates the white froth, some of the ocean's die off will be carried. We try to simulate this by using our skimmers. I could be off on this but it sounds pretty good.

[Doug1]

Interesting question Randy, we surmise that tidal surges can bring in new food supplies and help flush waste away, some organisms have adapted to life in the zone where tidal highs and lows are most apparent.
Tidal effect is not often addressed in home aquaria, tho some folks have employed Carlson or similar surge devices to replicate the rise and fall and wave action

[OneDummHikk]

Originally Posted by TheReefer12

Tides will help bring die off out of the water onto the beaches. When the waves crash and creates the white froth, some of the ocean's die off will be carried. We try to simulate this by using our skimmers. I could be off on this but it sounds pretty good.

Not really. While they do bring a little die off to the beaches, what gets deposited on the beaches is a very very small percentage of the "waste" in the ocean. And while the tides do have a small influence on wave action, there would be waves without tides. Most wave action isn't driven by tidal forces but more by wind forces. Think about the waves in a hurricane

As for skimmers, the biggest benefit of them is removal of waste but the waste can be removed without a skimmer (water changes, poop eating inhabitants, etc..). I would say aeration but Tom still hasn't convinced me of that one yet

[Doug1]

Originally Posted by OneDummHikk

As for skimmers, the biggest benefit of them is removal of waste but the waste can be removed without a skimmer (water changes, poop eating inhabitants, etc..). I would say aeration but Tom still hasn't convinced me of that one yet

Poop eating inhabitants don't remove waste unless they die and are removed from the tank, utilizing the food chain to consume waste only puts off the inevitable, and thats if nutrient imports are limited

[OneDummHikk]

Originally Posted by Doug1

Interesting question Randy, we surmise that tidal surges can bring in new food supplies and help flush waste away, some organisms have adapted to life in the zone where tidal highs and lows are most apparent.
Tidal effect is not often addressed in home aquaria, tho some folks have employed Carlson or similar surge devices to replicate the rise and fall and wave action

You couldn't truly replicate tides in a home aquarium simply because of sheer depth. Hard to replicate a 6-8 foot difference in water depth unless you had a +30 foot deep aquarium.

From what I have seen of the wavemaker devices (surges or not) isn't so much a tidal replication as much as simply a water movement feature.

The "wavemakers" simulate tides but not on the correct scale. They replicate it by reversing flow but they do it way way faster (30 seconds between rather than the 5 1/2 hours in the ocean).

I think if you had a Carlson device - one on each end - and cycled them ever 5 1/2 hours or so, you would be a lot closer to true tidal simulation than anything else on the market. The thing is, you would need a drain on each end that could handle the surge so that the water only moves in one direction. For me personally, I think the reversing of the water movement would do more good than the wave itself.

How do the tides effect feeding habits, and why?

[OneDummHikk]

Originally Posted by Doug1

Poop eating inhabitants don't remove waste unless they die and are removed from the tank, utilizing the food chain to consume waste only puts off the inevitable, and thats if nutrient imports are limited

Very good point.

[aquawolf]

In our club meeting, where Dr. Ron Shimek was the guest speaker, he brought up some very good points about our ineffectiveness to replicate a true ocean environment. If I recall correctly he had studies that showed the amount of flow over a 1 foot square section of reef to be some really high factor. He stated that we could never put that kind of flow in our tanks without busting out all of the glass because of the force that is behind it. This would be the same issue with tidal surge. That is a large body of water moving in one direction rapidly for an extended period of time.

I agree that wavemakers could never simulate that either. I have been curious about the Gyre flow setups for a while as they get all of the water in the tank moving in one direction and the randomness comes from the rocks and corals themselves. Yet again though the only thing you would be able to do is run it for so many hours one way and then switch it the other way for that many hours. Probably still not very effective when looking at it like that.

As for feeding habits, everything in the ocean is conditioned to eat according to the tidal flow. They know that when the tide is coming in it is time to rush into the shallows and begin feasting on the new biomass that is being pushed into the shallower waters. When the tide is going out they can wither hang back and try to pick up stragglers or get themselves back out to sea before they become landlocked.

I guess the only way for us to simulate that effect might be to feed a good amount of food twice a day at set times. As the tide times change every day we would have to adjust our feeding times as well. Of course this would mean that your system would need to be able to handle the extra food load as well if the inhabitants did not eat it all.

That is my 10 cents. I like this discussion so let's keep it going.

[OneDummHikk]

Originally Posted by aquawolf

In our club meeting, where Dr. Ron Shimek was the guest speaker, he brought up some very good points about our ineffectiveness to replicate a true ocean environment.

The only similiarities between whats in your living room and whats in the ocean is that they are both water, they both have salt in them, and they both have creatures living in them. The similarities pretty much stop there.

Since this is about tides, I will keep it there though

Originally Posted by aquawolf

If I recall correctly he had studies that showed the amount of flow over a 1 foot square section of reef to be some really high factor. He stated that we could never put that kind of flow in our tanks without busting out all of the glass because of the force that is behind it. This would be the same issue with tidal surge. That is a large body of water moving in one direction rapidly for an extended period of time.

The tides aren't really moving that rapid though. There is some tremendous force behind it but the speed isn't that great. The distance here in FL from high to low tide is an average of about 300 feet. At a 5.5 hour cycle time, that isn't that great a speed of water movement. Just don't try to stop it

As for the force, it has me baffled a little. If the force is great enough to break glass, why can divers swim in it without a lot of problems? There are places that they can't swim without the current pulling them, but there are also many many places where they dive without the current pulling them along.

Originally Posted by aquawolf

I agree that wavemakers could never simulate that either. I have been curious about the Gyre flow setups for a while as they get all of the water in the tank moving in one direction and the randomness comes from the rocks and corals themselves. Yet again though the only thing you would be able to do is run it for so many hours one way and then switch it the other way for that many hours. Probably still not very effective when looking at it like that.

If I ever manage to get moved and settled into somewhere that is mine, I am going to experiment with some ideas I have about wave simulation and water movement. 8-12 foot long tank, drains on both ends that can handle the flow, and inlets on each end. Massive flow in one direction, then reverse it on a 5.5 hour cycle. Basically a SQWD but on a 5.5 hour cycle. Not sure if it will work or not but curious to try it and see. It can't be that much worse than a 24" diameter 72" tall skimmer.

Originally Posted by aquawolf

As for feeding habits, everything in the ocean is conditioned to eat according to the tidal flow. They know that when the tide is coming in it is time to rush into the shallows and begin feasting on the new biomass that is being pushed into the shallower waters. When the tide is going out they can wither hang back and try to pick up stragglers or get themselves back out to sea before they become landlocked.

That is semi what happens when people turn the pumps off to feed. Most don't turn the PH'es off but turning off the return pumps does help simulate it.

Originally Posted by aquawolf

I guess the only way for us to simulate that effect might be to feed a good amount of food twice a day at set times. As the tide times change every day we would have to adjust our feeding times as well. Of course this would mean that your system would need to be able to handle the extra food load as well if the inhabitants did not eat it all.

The one part of tidal effects that you can't simulate is the difference in atmospheric pressure. But, lets suppose you had a tank setup that alternated direction of flow to simulate tides. How would the fish know when it was high or low tide and thus know when to eat?

[aquawolf]

Originally Posted by OneDummHikk

The tides aren't really moving that rapid though. There is some tremendous force behind it but the speed isn't that great. The distance here in FL from high to low tide is an average of about 300 feet. At a 5.5 hour cycle time, that isn't that great a speed of water movement. Just don't try to stop it

Of course that all depends on the area you are in at the time of tidal changes. Here in South Carolina with the Intercoastal Water Way, the tide comes rushing in like a major flooded river and foes out the same way each day.

As for the force, it has me baffled a little. If the force is great enough to break glass, why can divers swim in it without a lot of problems? There are places that they can't swim without the current pulling them, but there are also many many places where they dive without the current pulling them along.

I don't think he meant it would break the glass, I think he meant that the seams would not hold so the tank would fall apart at the siliconed joints.

A lot of the currents in the ocean are directed by the layout of the rock structures beneath the water. More wide open spaces they are not pushed and pulled so much, but tighter areas they will struggle just to stay in one place. This would be kind of like how no matter how much floww you put in your system you may still have some eddys based on the layout of the rocks. That is where your detritus is going to settle and bad algae may start to grow first.

If I ever manage to get moved and settled into somewhere that is mine, I am going to experiment with some ideas I have about wave simulation and water movement. 8-12 foot long tank, drains on both ends that can handle the flow, and inlets on each end. Massive flow in one direction, then reverse it on a 5.5 hour cycle. Basically a SQWD but on a 5.5 hour cycle. Not sure if it will work or not but curious to try it and see. It can't be that much worse than a 24" diameter 72" tall skimmer.

I know the Georgia Aquarium has a really big surge system setup using these giant bucket structures. Even as big as they are it does not seem to have that big of an impact on the water column or movement when they are dumped. I would definitely like to see what you come up with to practice on though.

The one part of tidal effects that you can't simulate is the difference in atmospheric pressure. But, lets suppose you had a tank setup that alternated direction of flow to simulate tides. How would the fish know when it was high or low tide and thus know when to eat?

Perhaps if you had a controller for your pumps that could also replicate the lunar cycle along with some type of automatic feeder system. Other than that I am not sure.

I do know that the fish in my tank are well aware that I am where the food comes from and if I put it in the tank they are going to eat it no matter what time, tide, or lunar phase, it may currently be.

[Seamore]

Not sure if this is a deep or shallow subject........sorry. Couldn't resist......

Tidal flow will be faster in some areas than others=Bernoulli's Principal, same volume increases rate of flow when constricted like in a tight intecoastal pass vs. a bay.

There are two things being talked about here one is flow and the change in flow the other is tides. Wave making is not tide making, and flow reversal over extended time only replicates the shift in incoming and outgoing flow. The rise and fall is improbable to replicate. How it effects the livestock... the massive flow floods food into and out of the depths and shallows away from protected areas and into the food chain. We know this as fishermen, theoretical top of the food chain (short of going one on one w/top aquatic predators in their enviornment) "fishing" can be done at any time "catching" is more likely if you know the tides and where they create congragations of foods. Understanding that tides are directly determined by the gravitational pull of the moon as it rotates around the earth, not barametric pressure, (the tide may be greater or lesser dedending on wind direction during tidal flow but that is about the extent of effect on tide by atmospheric press) then the timer on the PH or returne pumps shoud be on a lunar phase (not consistant hourly shift).
I'm fairly sure fish truly don't know it is high or low tide, I think they know how deep the water is and how much water they need to survive, they have learned behaviors, just like they light up when you enter the room around feeding time, noting the decrease/lul/stop/change in direction/lul/increase of flow triggers them to light up for feeding too. So you just have to time your entrance to the room to coincide with the slow and gradual change in the flow/depth in the tank from one side to the other (on lunar time) and you can play the part of the moon, although you will have to hide half of the time when you feed and skimm like well you know.
You may as well throw in a big sump and a rising and lowering overflow (lunar phase timer linked) to mimic the rise and fall of the tide (you could cheat and have two sumps on opposing timers with overflows at diffrent depths with valve that isolate each) and add the wavemaker but how often would you flood the tank/room?

Nature can be emulated closely often but rarely duplicated long term. So you can try to duplicate the effects of tide in your tank or accept that you are now the feed triger that makes your fish just as happy to see you as when the tide changed in the wild (if they were ever in the wild).

[OneDummHikk]

Come on people. Anybody else? I have replies for both but want to give other people a chance to chime in first.

Seamore, more later but think about a tank that has a bulkhead 6" from the high water mark. You slowly drain the tank down to that bulkhead, over a 5.5 hour span, then put it back in 5.5 hours. The biggest issue there is trying to find a pump that will pump that slowly. In a 120, that equates to about a 5gph pump.

[Seamore]

Randy,
There may not be anyone else....
This is not the most read post, probably because it requires some knowledge and the desire to think, and discuss. Effort in discussion for the sake of gaining understanding is not going to compete well while that other Phelps fish is on display in that other water box on that other glass box that occupies our space and time. Sometimes it's not the quantity of the conversation but the substance that is constructive. For example the bulkhead idea, never would have thought of it and I think it is do-able, I guess thats why I know there is so much left for me to learn. Having other thinkers to bounce ideas around is a resource beyound price. If you want to gather the masses then you'll have to change the topic from tides to something with mass appeal, sad but true. If your topic was Pamela Anderson's Tank you'll double the hits, may not learn anything except what sells on TV sells on TRT. Let's face it, this is not the Algonquin round table, the fact that there are 5 people talking about the relevance of tides may be all you have. Intrest like the tide will rise and fall to diffrent levels each day and we can't control it.

[OneDummHikk]

Sad but true Seamore, sad but true. Maybe I should ask Tim to move the thread to The Think Tank area.

As for the bulkhead idea, I think 6" down is too low on a 120. My 120 is 24" tall. The 6" would represent 1/4 of the water depth. If the reef is under 50 feet of water and the tide drops the water level 4 feet (not sure of either of those dimensions though), then the tide drops it 1/12th or so of the depth. That means on a 24" tall tank, you only have to drop it 2" to truly mimic the tide dropping. It isn't the water depth itself that triggers tide related events, its the drop in pressure and to mimic that, you (I think) would need to drop it relationally to what truly happens.

One of the issues with the bulkhead is trying to find a pump that would pump that slow. At 2" of depth, in a 24x48 footprint tank (my 120), you are only removing 5 gallons or so of water (2x24x48/231). You would only be removing/replacing 1 gallon per hour. At 6" down, you would be doing ~3 gallons per hour. A 1/4" tubing running on a gravity feed or a siphon would be faster than that.

Another thought I have had was to build a custom overflow box that is designed similar to locks in the Panama Canal. If the overflow box had a door on it that was raised and lowered, it would raise and lower the water level in the tank. That would solve the issue of the slow flow rate.

If you had a 6 or 8 foot tank (the longer the tank, the easier it is to do) and had a wavemaker type setup, adjustable overflow boxes, and drains on each end of the tank. The wavemaker would create the waves, the wavebox would be the water movement, then it returns back to the wavemaker that is on. You could create directional waterflow that could be adjusted based on a 5.5 hour tidal cycle. The bad part is that you wouldn't know, until it had run for a while, whether you wasted your time doing it or not

All of the water would have to be able to be drained from the wavemaker. Otherwise it would simply rebound back and cause problems with creating waves and having bi-directional flow in the tank.

Build a 20,000 gallon tank with a beach, with rising and lowering tides

[OneDummHikk]

Originally Posted by aquawolf

Of course that all depends on the area you are in at the time of tidal changes. Here in South Carolina with the Intercoastal Water Way, the tide comes rushing in like a major flooded river and foes out the same way each day.

That isn't just the tidal flow at work though. It is also the phenomenon of putting the water into a smaller area (the river versus the beach). The same effect happens here in Jax with the ICW but on the beach, you don't see that. The ICW does it because of the amount of water you are moving. To move it in a smaller area, you have to speed it up.

Originally Posted by aquawolf

I don't think he meant it would break the glass, I think he meant that the seams would not hold so the tank would fall apart at the siliconed joints.

Interesting. Will have to see what I can find out about that part of it.

Originally Posted by aquawolf

A lot of the currents in the ocean are directed by the layout of the rock structures beneath the water. More wide open spaces they are not pushed and pulled so much, but tighter areas they will struggle just to stay in one place. This would be kind of like how no matter how much floww you put in your system you may still have some eddys based on the layout of the rocks. That is where your detritus is going to settle and bad algae may start to grow first.

The currents on the reef are affected by it, the general currents in the ocean aren't. Small subtle technicality there Either way, the currents in a tank are definitely affected by the rockwork. People spend too much time fighting dead spots for it to not be affected

Of course, if you have ~12,000 gallons of flow in a 125G tank (Geoff) then I don't think you have true dead spots. You will have spots with less flow but it still wont' settle in the slow spots. Makes me wonder how much detritus would settle in a 12G nano tank with a mag18 CLS on it!

Originally Posted by aquawolf

I know the Georgia Aquarium has a really big surge system setup using these giant bucket structures. Even as big as they are it does not seem to have that big of an impact on the water column or movement when they are dumped. I would definitely like to see what you come up with to practice on though.

That is basically what the Carlson Surge Devices are that Doug mentioned. A container above the tank that when it gets full, dumps the contents into the tank, then fills back up. Like a constantly flushing toilet. And that is about what they sound like - a toilet flushing. Very noisy things. They do move the water column though. I haven't been to the Georgia Aquarium but it may be that the amount of water they are dumping isn't enough to cause a lot of change in the surface level of the tank. Five gallons into a 90 causes a pretty big surge (from me tinkering with one).

The 125 I have I have to build overflow boxes for it. May try the sluice gate idea on one to see if I can make it work. I think, although not positive, that I have a gear set in my Legos that will do what I want to try. They are plastic - Reef Safe!

One issue with the sluice gate idea is that the waterflow through the sump will be slower while the gate comes up than it is while the gates coming down unless you modified the flow from the pump.

Originally Posted by aquawolf

Perhaps if you had a controller for your pumps that could also replicate the lunar cycle along with some type of automatic feeder system. Other than that I am not sure.

You would need DC pumps and a controller. Most waveboxes are built with Tunze 6200 series controllable pumps. Two pumps and a controller would be minimum. New, thats close to 1500 dollars. My fish/corals don't need tidal influence that badly!

http://www.marinedepot.com/ps_Aquari...tream_kit.html

Tunze 6201 - 505 each
Multicontroller - 271 each

Originally Posted by aquawolf

I do know that the fish in my tank are well aware that I am where the food comes from and if I put it in the tank they are going to eat it no matter what time, tide, or lunar phase, it may currently be.

Mine stalk me when I am around the tank. They are the same way. I put my hands near the tank, they want food.