changing to low flow at night time?

[fijiblue]

Regardless if that is your point or not, your information is incorrect.

If any of you have been in the pacific where these corals are grown, you will see that over the course of 24 hours the tide comes in and goes out twice (as with everywhere else for that matter). During low tide, there is much less current than when it is high tide. Low tide brings up sand bars and creates pools that are shallow. I have experienced this many times, one particular scary time when the tide was coming in and revived a local rip current that was extremely hard to deal with (I would be happy to post video of it if anyone is interested).

The point is, yes there technically is lower current at night for six hours when the tide is out. Again, if you want to recreate this in your tank, you should have the flow high and low in 6 hour segments.

 

[shred5]

<a href=showthread.php?s=&postid=14431758#post14431758 target=_blank>Originally posted</a> by fijiblue
Regardless if that is your point or not, your information is incorrect.

If any of you have been in the pacific where these corals are grown, you will see that over the course of 24 hours the tide comes in and goes out twice (as with everywhere else for that matter). During low tide, there is much less current than when it is high tide. Low tide brings up sand bars and creates pools that are shallow. I have experienced this many times, one particular scary time when the tide was coming in and revived a local rip current that was extremely hard to deal with (I would be happy to post video of it if anyone is interested).

The point is, yes there technically is lower current at night for six hours when the tide is out. Again, if you want to recreate this in your tank, you should have the flow high and low in 6 hour segments.

Tide happens day or night. Waves are calmer at night.. Dive at night once. During the day when I dive I can in allot of spots sit pretty much constant except for the back and forth motion.. The back and forth is produced by waves which are less at night in most cases. There are always exceptions like where the tides are funneled through tight spots. Also look at the wave action in shallow water or reef crest where allot of the sps grow. They are absolutely getting pounded by waves. The tide can affect the depth the water is in these areas but they literally get pounded by waves. The deeper you go the less the tide affects the reef. I have dove in 100 feet of water and saw a wreck get flipped over by waves. I am not saying the tide has no affect but the real difference is the waves.

Dave

 

[fijiblue]

Also look at the wave action in shallow water or reef crest where allot of the sps grow. They are absolutely getting pounded by waves.

Im sorry, but this is one of the biggest misconceptions in this hobby. I am in the process of uploading video to help this conversation...

 

[fijiblue]

Low tide:


Tide coming in:


Most of the acropora I have seen on reefs have been in deeper, calmer water.

 

[serpentman]

Although I agree for the most part, the video does only reflect one locale. Some reefs become completely exposed to the air when the tide is at its lowest. In general, most reefs are usually only "pounded" during sizable storms or hurricanes. When that occurs, substantial damages results allowing the reef to repair and colonies to reproduce by natural fragging. We may be arguing semantics however, as pounding motion is relative.

Again, there are exceptions to every rule. My personal take on reducing flow at night is more for fish as they don't have as many choices to hide from flow as they do in the wild. I like to decrease mine also to vary the pattern so when the pumps ramp up in the am, any detritus that may settle gets swept up and dealt with.

 

[shred5]

<a href=showthread.php?s=&postid=14432517#post14432517 target=_blank>Originally posted</a> by fijiblue
Im sorry, but this is one of the biggest misconceptions in this hobby. I am in the process of uploading video to help this conversation...

how is this a misconception?

How many soft corals grow at the reef crest or very shallow water? I never said this is the only place sps grow. But almost all the coral in this area is either sps, encrusting or bouldring type corals, Soft corals would be ripped to shreds... almost all the corals in this area are some sort of stny coral in which the polyps can hide.

Dave

 

[fijiblue]

I can show you more locations of the same thing if you would like

I agree that this is only one location, but the reefs that are exposed to air are not the norm as far as the diverse species of acropora are concerned. Proites, Humilis, Samoensis, some hyacinthus and a few others are more likely on the upper reef being exposed at low tide.

Shred - I see what you are saying with tide and waves, but understand that one area that receives decent wave action will be less active when the tide drops and turns that area into a pool. Misconception because majority DO NOT get "pounded" by waves as serpentman pointed out. I beg to differ with the soft coral - did you not see all the sinularia and soft corals in the video? They are in shallow water. Huge colonies (bigger then cars) are found in shallow waters.

I agree with macreefster Cutting down flow at night when the invertebrate and fish are consuming the oxygen that was produced during the day might exacerbate the problem of lower ph and less dissolved oxygen even more.

 

[shred5]

<a href=showthread.php?s=&postid=14433066#post14433066 target=_blank>Originally posted</a> by fijiblue
I can show you more locations of the same thing if you would like



Shred - I see what you are saying with tide and waves, but understand that one area that receives decent wave action will be less active when the tide drops and turns that area into a pool. Misconception because majority DO NOT get "pounded" by waves.

Again you are only picking one part of what I am saying.. I am using one part as a example or a exception because it is the most extreeme case.

Dave

 

[fijiblue]

???

 

[fijiblue]

Since this is so much fun digging up some of this video, here is another cut of soft corals in 3 feet of water and some beauties I hope are still there and growing well.

 

[Rouselb]

Lets ask the question a different way. Has anyone experienced any negative results by decreasing flow at night? Are there any results that prove or warrant us to decrease flow. I know some want to decrease noise, but thats not what im looking for. Coral growth, PE, coloration, fish behavior, disease.

 

[gaetanocallista]

<a href=showthread.php?s=&postid=14433445#post14433445 target=_blank>Originally posted</a> by Rouselb
Has anyone experienced any negative results by decreasing flow at night? Are there any results that prove or warrant us to decrease flow.

That's a good question!
Anyone?

 

[Heinz]

<a href=showthread.php?s=&postid=14423134#post14423134 target=_blank>Originally posted</a> by Rouselb
There's not less flow at night! Why would you think that?

because thats how it is ?

have you ever been to the see ?

8 out of 10 times the see is calm at night, at least everytime i was there ,

 

[Rouselb]

hah.. yes i have been to the sea. I have been diving several times in the evening, and the water movement across the corals appeared to be the same as it was in the day. But thats my take on it, thats why i asked the question a different way. Our tanks are no where close to the amount of water movement you see in the ocean. So we should be asking if there have been any positive or negative results in the aquariums we have. Here is a great article on surface currents and deep water currents:

http://cubanology.com/Articles/Ocean_Currents_The_Distribution_of_Life.htm

 

[ChuckG]

I didn't read all the responses so this may have been covered.. but tides are highly variable based on moon phase, location, and seascape. That said they do not flow for 6 hours then sit for 6 hours then flow another 6 hours.

Typically there is always and average amount of water movement be it incoming or outgoing. As you approach and reach the extremes either at the high or low tide, the amount of time spent flowing at any one rate is decreased. Extreme high or low tide where there is very little water movement is typically not longer than twenty minutes to an hour in duration. Again this is highly dependent on how water flows into and out of the location.