Do you reduce water flow at night?

[class clown]

Until recently, I always decreased the intensity of my powerheads at night. Admitedly so, i had diatoms in the sand when I woke up in the morning.(yes I know overfeeding, but I can't help it, I have anthias) . Recently however, I got a new computer controller and haven't quite figured out how to program it to reduce the waterflow intensity at night.. Well, unexpectedly, I no longer have any diatoms. hmmm...now the lack of diatoms could also be attributed to the addition of a new phosban reactor too, but after chatting with a friend tonight, I wonder if it has more to do with the steady random flow left on all night than the reactor.

So.. I'm interested in what you do.. do you keep the same intensity of flow in the day vs. the night or do you reduce it? Have those that have tried both noticed a similar phenomenon - diatom reduction? are there benefits to the fish/corals for reducing it at night? are the natural currents in the sea reduced at all at night?

 

[Krish]

I've never reduced any of my flow before and never had any issues. I figure if the ocean will pound the waves day and night on end sometimes, it must be fine. As for how you can reduce it at night with the computer controller, I couldn't say. I know Tunze streams have a sensor that will put certain models in night mode to slow down the flow, but apart from that, all I could say is put the pumps on timers to have them shut down at night

 

[class clown]

Well, I'll figure out the programming if I decide to continue to do it. But I'm not so sure I'm going to reduce it. Any benefits to reducing? Why do companies put this function on their wavemakers if no benefit? less stress on the fish?

Looks like we're 2 for 0 on keeping the flow the same during the day vs. at night btw. Other opinions?

 

[DonW]

I agree let it go 24/7

Don

 

[jnarowe]

I have always reduced flow by about 6400 gph just to help the fish relax. That's about 1/3 less.

 

[shallowreef]

My main return stays at the same power 24/7 but my tunze drop to 30% at night and then 100% when the halides come on.

 

[SueT]

I do slow things down at night due to the high flow I have going during the day. Polyps are blowing so much I figure that since the ocean does slow down at night some I give the corals a chance to catch up. I don't have any diatoms bloom in the mornings so alls good.

 

[returnofsid]

I've recently read that reducing flow at night is actually somewhat bad for the tank. After lights out is when PH tends to drop...and oxygen levels in the water also tend to drop. Reducing flow will increase the drop in oxygen levels. Don't know how true any of this is but it's something I've read in more than one place recently.

 

[jnarowe]

That is true. In fact in my FW planted tank I run two large airstones when the lights go out to help keep the pH and oxygen exchange up. But reducing flow is much different than no flow, IMO. I believe that as long as there is enough flow to move the surface a bit, that the O2 exchange is still high enough to not cause problems. Anyone have thoughts on that?

 

[davidabrown66]

I reduce my flow at night out of necessity, since I have heat issues stemming from my pumps. The increase in heat will keep my chiller working on and off thru the night without lighting

I've tried different pumps, and cleaning them etc. but I've been told that a 150 gal acrylic tank that's only 4 feet wide and 30 in. tall and 1/2 inch thick retains more heat than others of the same volume. I push about 40 - 45 times the tank volume per hour. I keep my house at around 66 degrees unless it's summer, and it's still an issue.

I have a Dolphin Ampmaster 3000 on CL, a Sequence Barracuda on a CL, and an Iwaki for my return. My sequence pump is on the same timer as my halides, but I still retain a flow of around 20x's per hour at night. I don't see any diatom build-up, but I notice a big drop in PH after the first three hours after the lights go out. In fact, the PH adjusts from 8.2 to 8.0 in that time, and then holds there.

 

[class clown]

K - so here is what I'm hearing:

Pro's for reducing flow:
1) mimics the ocean (is that true? Do we know for sure? i've heard this before, but do we have any oceanographers that can confirm? Also, seems like Krish thought maybe the opposite to this by his post)
2) let's the fish & polyps relax - Ok, I buy half of that. (Fish relax = OK yeah I can see that, but more times than not, they know which caves to go hide in at night which block them from the flow anyway, right? As for corals, polyps extend larger at night to come out to feed, maybe a more relaxed environment would make it easier for them to extend and hold onto food, but then again, not so much food is circulating at night if we cut down the flow. hmm.. that's a toughy)
3) may help with temperature control due to pump(s) heating the water - ok, not universal to all systems, but I can see your point.


Con's for reducting flow:
1) Oxygen levels may drop if surface agitation isn't enough -k I can see that, but is it a noticable amount?
2) Diatoms to collect easier in sand

So.. let the discussion continue.....

 

[Herefishyfishy]

I keep my return through the fuge at full power but use the controller to turn the SEIOs down, reducing the currents. Running 2 each 2600s inside blowing across the corals from both ends of the 180.

 

[redrooster]

I keep mine the same, but don't have any science to base this on. Its just easiest and in my low maintence style if it's not broken don't fix it. I did notice though that when I used to have like 22x flow on the tank I got diatoms on the gravel over a week or so, but now with 35x flow it takes about 2 weeks to build up. I do think your gravel will brown quicker with less flow, but as you are finding out there are many other implications that it sounds like you are doing a good job trying to think through. I hope you can dial it in and get the results you are looking for!!

 

[Reefdaddy1]

I have reduced the the flow at night, Mimics the Ocean. ALl I ever done was turn off the CL, Powerheads and al remain running. Never had a problem with anything doing this. Will remain doing it until something is shown that is really bad.

 

[jezzeaepi]

I see no reason to reduce flow. Few people are pushing the edge of too much flow. Therefore lessening the flow of your tank at night would put the tank even further away from the required flow. IMHO the benefit of helping the fish rest is not worth the deletrious effect of lessened flow.

 

[class clown]

I have reduced the the flow at night, Mimics the Ocean. ALl I ever done was turn off the CL, Powerheads and al remain running. Never had a problem with anything doing this. Will remain doing it until something is shown that is really bad.

K - definatley not the first time I've heard that lessor flow mimics the ocean. Are we positive about this though? I'm not saying it doesn't, just want some pretty concrete info to support that the currents in the ocean really are reduced at night. Any studies we can reference?

IMHO, I think mother nature knows best - she's been doing it right for more years than I could count, so I'd like to mimic what is done in nature - whatever that may be. Anyone know if this is really really true? And if so, by how much? i.e 30% reduction at night? 50% reduction at night?

 

[Herefishyfishy]

Hey Mon, Sound like time for you to go down ta Jamaica (or the Bahamas)

 

[DonW]

K - definatley not the first time I've heard that lessor flow mimics the ocean. Are we positive about this though? I'm not saying it doesn't, just want some pretty concrete info to support that the currents in the ocean really are reduced at night. Any studies we can reference?

IMHO, I think mother nature knows best - she's been doing it right for more years than I could count, so I'd like to mimic what is done in nature - whatever that may be. Anyone know if this is really really true? And if so, by how much? i.e 30% reduction at night? 50% reduction at night?

Mimics the ocean? Even with a tank running 100+ times turn over your not moving as much water as a reef on even the calmest of days or nights.
So you have reduced flow to begin with and by turning off the pumps at night you have even less flow.
Less flow means less gas exchange and detritut settling. Less gas exchange means larger ph swings. Anoxic zones change as dose overall stability.

Sound good in theory, but whatever works for the individual.

Don

 

[Krish]

mimics the ocean (is that true? Do we know for sure? i've heard this before, but do we have any oceanographers that can confirm? Also, seems like Krish thought maybe the opposite to this by his post)

LOL! Anyone want to visit and go for a swim at night?? The ocean at night can be just as "violent" or even more "violent" in the night than in the day. I go for rides some nights along the shoreline and you will find water splashing up over the rocks. I think it is safe to say "generally speaking" nights are calmer than days as you will probably have more nights out of the year with calmer waters than the days from my observations, but still not always the case...It's mother nature. IMO it would be too broad of a statement to say nights are always calmer than days when some nights are worse than some days and vice versa. But like Don said, go with what works best for you

 

[class clown]

OK... So I think we've proved here we'll never have as much current as in the real ocean regardless day or night. So, can't really mimic mother nature no matter what we do.

Half of us say reduce it at night, the other half say keep it the same at night. I think we've all been succesful at keeping corals and fish happy doing it both ways.

I've personally have seen visual improvements in the last week or so by leaving the random flow on all night judging by the detrius free sand. I haven't noticed any adverse effects of doing so on the animals. So, for the time being, that's what i'll stay with. "To each his own" until there is conclusive evidence one way or the other.

thanks everyone.