Turning down the flow at night?

[bsmith065]

I've just completed a re-design of my 90 gallon tank... complete with an over the top closed loop system and some WavySea wavemakers.......

Lots of flow.... some nice current going there.

I currently have the system turning on with the lights... so I let it "rest" overnight... and let the critters feed, based on some input I had from a few people.

I was reading recently however that oxygen levels get low at night, and that is it best to keep everything going all night long.

Any thoughts out there?

[musty baby]

Are you saying you stop all your flow at night? That would be a bad idea.

Water flow in the ocean doesn't stop at night...

[drummereef]

Agree. And when you turn the flow down, oxygen levels go down thus making the pH drop. When the lights go out the pH drops. Keeping flow going will help minimize that swing. I would leave your flow on 24/7. Just my opinion of course. ;)

[roons]

i did this , until i watched a royal gramma get shredded in my tunze, it runs the same day and night now flow wise

[bsmith065]

What does day/night have to do with shredding a fish?

It decide to make a home in the Tunze while it was off... that's a funny thought... well until it turned on.

So is there no truth to the whole... the ocean calms down at night school of thought?

[jjmg]

Here in the northern Gulf of Mexico the waves will often lay down at night, however; the tides continue with no change. Some days there is a heavy tide and some a slack tide. It has nothing to do with night or day, but more the moon phase. I'm sure the worlds reefs also experience less wave action at night due to cooling and less wind, but the tides run without regard to night or day.

[houser]

how many times do you wake up and the surf is pounding and glassy when the night before it was small?
Night mode? That's for your piece of mind - not your fish!

[ACBlinky]

Turning the pumps off at night is a BAD idea IMO. It surprises me how many people want to turn the rate of flow in their tank down after lights-out -- ocean currents don't slow as the sun goes down. It's important to have the skimmer running and keep tank circulation up at night to avoid lowering pH and O2 -- it's not unheard of to lose fish due to oxygen levels falling too much overnight, especially tangs and angels. Many of us run a refugium on a reverse photoperiod as well, so the chaeto is photosynthesizing and adding O2 to the water all night while the lights are out on the display.

[sumpinhabitant]

I run different flow occasionally in my tank, thru my controller. Not just at night . It doesen't hurt to switch thing up a bit but I wouldent stop flow completely.

[bsmith065]

Seems no one out here wants to buy into the "Night Mode" theory.... I guess that's just another trap for us less experienced to fall into.... Going downstairs to plug my closed loop into a different socket :)

Once again... thanks to all of you.

[roons]

uh, when the tunze is off the fish go in it, capeche?

[danch]

<a href=showthread.php?s=&postid=8915907#post8915907 target=_blank>Originally posted</a> by drummereef
Agree. And when you turn the flow down, oxygen levels go down thus making the pH drop. When the lights go out the pH drops.

Doesn't change your point at all, but technically it's increasing CO2 that drops pH. In planted FW tanks, people run very high levels of CO2, dropping the pH to near 6, but there's still plenty of oxygen for the fish.