Night time water movement

[BlazinNano]

So I have been thinking of an idea. I don't know if it would work or if it is even a good idea. I have been thinking about finding an electric valve in plastic that I can hook up to a relay. When the relay kicks on the valve will open and my return would be split sending some water back to the sump. Thinking about having the valve open about an hour after the lights go off till about 2 hours before the lights come back on. If this is a good idea what percentage should I cut down the flow to my tank? 25%? 50%? Any ideas?

 

[MoneyPit]

Well I get the idea I think... Do you have other forms of water movement such as powerheads ? If so I think those would need to be cut back/off to get the desired effect. What size return do you have and what is it actually pumping? I would suggest trying to cut back prob 25% depending on current flow. You still want to turn your tank water over enough. So more than that might not be to good. Good Luck !

 

[btkrausen]

Yeah, I think you'd want to cut the flow on powerheads, and not the turnover rate to achieve this. Cutting the turnover rate would just decrease the amount of tank water sent to be skimmed, heated, polished(carbon), and keep a steady level of oxygen in the tank.

 

[BlazinNano]

Looks like I need new powerheads then. Don't think you can slow down a koralia.

 

[btkrausen]

If you had a controller, you could simply just turn one of them off if you wanted to reduce flow inside the tank.

 

[BlazinNano]

Ok now I have another question. Does it even help to reduce flow at night? I know the sea normally gets calmer at night but most corals have been aquacultured so long they are use to our tanks.

 

[btkrausen]

I've never reduced flow in my tank at night, although my Vortechs will do it. Never had an issue with it, but never tried it to compare results either.

 

[mfinn]

My Tunze controller has a night feature which turns both of the 6105's to the lowest setting when the lights go out.

 

[fsu1dolfan]

Ok now I have another question. Does it even help to reduce flow at night? I know the sea normally gets calmer at night but most corals have been aquacultured so long they are use to our tanks.

Once I got my mp10 I was thinking the same thing but I have yet to slow it down at night. Since I feed during the day, I figure the extra flow at night would be good for the corals that try to catch some food.

 

[drainbamage]

I know the sea normally gets calmer at night

Really? I was under the impression that though wave crests caused by wind and air pressures were lessened at night time, all the same tidal forces and currents were the same. So unless simulating an extremely shallow reef, there's not really a reason to reduce water flow during 'nighttime.' But can't find a lot of info on this, except ironically people talking about it on reefing sites, lol.

edit- thought of something- if there was actually less motion in the ocean (giggle) at nighttime, wouldn't corals have less purpose to be out feeding at nighttime?

 

[Electrobes]

I actually use my MP10 on night mode setting from 7pm till 7am. I am not sure if it's because I have a softy tank, but I think my tank appreciates it. Maybe it's easier to feed on particulates when the water flow slows down?

 

[swannyson7]

edit- thought of something- if there was actually less motion in the ocean (giggle) at nighttime, wouldn't corals have less purpose to be out feeding at nighttime?

I've always heard that the current slowed down at night as well, so this is just a shot in the dark...
Perhaps the lack of competition for food with fish is the primary reason that corals tend to feed at night. Or maybe it has to do with the weak feeding responce of many corals and their inability to properly consume the necessary food during the stronger current during the day.

 

[Jcr's Reef]

Low tides and calmer water at night IMO.

I have also noticed greater polyp extension (SPS/LPS) when turning my Vortechs down Manually at night. I don't do it all the time though. During the day my PE is only about 1/2 on my SPS with high flow and is constantly extending and retracting. At night they are fully out and stay out.

 

[CJO]

Really? I was under the impression that though wave crests caused by wind and air pressures were lessened at night time, all the same tidal forces and currents were the same. So unless simulating an extremely shallow reef, there's not really a reason to reduce water flow during 'nighttime.' But can't find a lot of info on this, except ironically people talking about it on reefing sites, lol.

edit- thought of something- if there was actually less motion in the ocean (giggle) at nighttime, wouldn't corals have less purpose to be out feeding at nighttime?

That's correct. The tidal forces are the same and the currents are relatively unaffected by the time of day in all areas but the reef crest zone. In that zone, things are truly more calm at night. Corals feed at night primarily because that is when their food is out!

CJ

 

[butts182]

Tidal currents (due to the moon) are the same during the night and day. Underwater flow is also the same (i.e. the Gulfstream doesn't slow down at night). Usually the wind is less during the night, which in turn reduces the height of wind-born waves or chop, but has little effect on swells (like DB said above). unless you are trying to simulate a reef in the surf zone that is affected by wind waves, i don't think that reducing the flow does anything for your tank. but that is just my opinion as a hobbyist and a coastal engineer.

 

[Eddie Baby]

+1

Tides vary each day - you don't always have high tides at day and low tides at night. Current of one form or another is always flowing. If you are keeping a tank that mimics a reef crest zone, then it makes sense to dial back a bit at night.

 

[Travisw30]

So how do I set up my mp10 to make lees movement at night? Does it have an internal clock?

 

[Wy Renegade]

Interesting thoughts, although like others have said, not sure I see any valid reason to slow flow down at night. Anybody have an idea of what types of corals specifically occur within the reefcrest zone?

 

[tangboy]

Currents stay the same, the wind changes due to which is warmer/colder (warm air moves to colder areas to balance out temperatures and since sea water stays constant, and the land heats up/cools down faster, you have changes in the wind) but only affects the first couple of feet above the ocean.

Corals sweepers come out at night due to the fact that fish have a harder time feeding at night so smaller organisms feel "safer" to come out to feed themselves plus there is no sunlight for the corals to absorb their energy from so they switch to feeding through their polyps only.

I turn my flow down at night so I can feed my corals and not have it blowing all over the tank. That's why I turn my PHs off...

 

[drainbamage]

Interesting thoughts, although like others have said, not sure I see any valid reason to slow flow down at night. Anybody have an idea of what types of corals specifically occur within the reefcrest zone?

Some zoa's, obviously many acro's, basically things with very sturdy 'bodies' are going to be the ones able to tolerate those incredibly powerful areas. So think things like thicker bodied acro's (staghorns, probably not birdsnests) maybe some maze corals, things like that? I know I've seen a few books with pictures of massize zoa mats exposed at low tides- however that doesn't prove conclusive because low tide will affect a closed lagoon (low surf zone) just as much as an open reef (powerful wave zone) equally.

Sorry guys- not trying to say that those turning their PH's down/off at night are doing something horrible, I was just commenting on the theory behind it as it's something I've heard my entire reefkeeping life, and never understood it. Been trying to dig into it a bit more lately just for my own interest and it seems to be something with a lot of misconceptions based on our visual and aural senses being dominated by an above water line beliefs that we then transcribe to the bellow waterline reality. Err...yea, something like that.