How long can pumps be off during the day?

[Tired]

When I spot-feed my corals, I shut the flow pump off so the food doesn't immediately get washed away. Everything eats pretty quickly, but I never know how worried I have to be about accidentally forgetting to turn the pump back on for a couple hours. I assume it won't do things any harm for the water not to circulate for an hour or two, but I thought I'd double-check. 

 

Assuming it's during the day, and the tank isn't crazy overstocked or overheated, is it safe to leave pumps off for a couple hours? 

[AquaVaj]

I've done deep cleaning and water changes that last up to an hour and things were fine. At 2 hours I'll start worrying though. I tend to be forgetful so I'm thankful I have my apex. Just turn on feed mode and it turns everything off for 5 mins and automatically turns them back on. If it wasn't for this I know for sure I'll forget plenty of times. 

[jservedio]

1 hour ago, Tired said:

Assuming it's during the day, and the tank isn't crazy overstocked or overheated, is it safe to leave pumps off for a couple hours? 

Yes

[RedCrow]

Oxygen depletion is what you’re going up against. In a lightly stocked tank you could easily go 24 hours +. The more oxygen-consuming organisms you have, the less time till oxygen depletion. Keep in mind that at night, plants cease photosynthesis and begin to consume oxygen 

[Tired]

Yeah, I wouldn't turn the pumps off at night. Especially not once my macroalgaes grow out. I don't think a lot of people know that plants use oxygen at night, but if you do know it, it explains a few things. Like why closed ecosystems don't work when we try to make them. Though I have wondered about a large enough terrarium that part of it could be lit for the day, then the other half at night, with slight overlap. Like 'fuge lighting.

 

Full disclosure, I've left the pump off for 4-5 hours a couple times. Nothing ever looks stressed when I do, but the tank isn't very dense with livestock yet. I imagine a tank packed with corals would have more trouble.

[mcarroll]

9 hours ago, Tired said:

When I spot-feed my corals, I shut the flow pump off so the food doesn't immediately get washed away. Everything eats pretty quickly, but I never know how worried I have to be about accidentally forgetting to turn the pump back on for a couple hours. I assume it won't do things any harm for the water not to circulate for an hour or two, but I thought I'd double-check. 

 

Assuming it's during the day, and the tank isn't crazy overstocked or overheated, is it safe to leave pumps off for a couple hours? 

I suppose it depends on the coral, but many (at least) actually depend on the current for proper feeding.  Rarely are waters on a reef actually still...so why would corals require that no-flow condition for feeding?  Wouldn't make sense in 99% of the locations where they live.

 

Not only that, but the food will require flow if it's going to be kept off the ground and in circulation so it can be grabbed as food later on.

 

So I might shut down a filter or a skimmer when feeding, but I rarely or never shut off flow pumps.  (And I usually don't shut off anything...I run my filters with no media and skimmers stop skimming automatically once food oils hit the water and lower water tension.  Bubbles can no longer form well.)

 

The only context I can think of where corals could regularly be without flow (tantamount to breathing) for hours at a time is shallow water corals during low tide.  Not all corals are adapted for that kind of stress though....and arguably most corals in the hobby today are deep water corals.  Depends what's actually in your tank of course.

[Tired]

I'm feeding rock flower anemones, acans, and occasionally a zoanthid colony. I put the food straight on top of them, and if I try with the pump running, it just gets washed away. The ones that need the current to feed are mostly SPS, gorgonians, and other things with a ton of tiny polyps, right? I do disperse a bit of reef roids into the tank when I start the pump back up, for the assorted filter-feeders. Especially since one of those nice little red feather dusters with the white tubes popped up somewhere visible. 

 

How do corals actually, physically breathe? Do they just exchange oxygen with the water, like their whole body is a gill, or like a frog's skin? They don't seem like they have much in there- pretty much just a mouth and some gonads. 

[mcarroll]

23 minutes ago, Tired said:

How do corals actually, physically breathe? Do they just exchange oxygen with the water, like their whole body is a gill, or like a frog's skin?

I know jack about frog skin, but yep they breathe via the skin and so-called "boundary layer" that's created by the water and their mucus layer.

 

 

Check this out (from 1977!!!):

Water flow and the morphology of zoanthid colonies

http://ibdev.berkeley.edu/labs/koehl/pdfs/Zoanthid_Colonies_1977.pdf

[mcarroll]

(Nut-shell summary: polyp shape and flow velocity work together to make the coral catch food...corals control their polyp shape...our corals are smarter than we are! 😉)

[mcarroll]

On that "smarter" comment....have you heard of crochet reefs?  It's a mathematics lab assignment you and I can appreciate!!  

 

Check it out:

https://www.margaretwertheim.com/crochet-coral-reef

[Snow_Phoenix]

10 hours ago, Tired said:

Assuming it's during the day, and the tank isn't crazy overstocked or overheated, is it safe to leave pumps off for a couple hours? 

^Yes.

 

When I feed my dragonets and other fish, I usually leave my pumps off for an hour to 3 hours (until most of the food is gone, and the fish are full enough that they start to chase their reflection on the glass instead of continuing eating). No ill-effect on any of the livestock when I do this, and my tank is quite overstocked/stocked heavily. 

9 minutes ago, mcarroll said:

On that "smarter" comment....have you heard of crochet reefs?  It's a mathematics lab assignment you and I can appreciate!!  

 

Check it out:

https://www.margaretwertheim.com/crochet-coral-reef

That's actually amazing! 😮 

[Tired]

Frogs can exchange oxygen into the air or water through their skin. Here's something cool- a species of very wrinkly frog that, in the wild, never surfaces to breathe. It has so much surface area that it can breathe entirely through its skin. They can breathe air in captivity, when they need to, but individuals in the wild can go their whole lives without ever swimming to the surface of the lake they're from. It is unfortunately named Lake Titicaca.  https://animaldiversity.org/accounts/Telmatobius_culeus/

 

That's really interesting about the coral shape. The zoas are better at snagging food than I would have thought, evidently. 

 

I can't crochet, but I've done a bit of needle felting of corals. I'll try to find it for later.

[Snow_Phoenix]

8 minutes ago, Tired said:

Frogs can exchange oxygen into the air or water through their skin. Here's something cool- a species of very wrinkly frog that, in the wild, never surfaces to breathe. It has so much surface area that it can breathe entirely through its skin. They can breathe air in captivity, when they need to, but individuals in the wild can go their whole lives without ever swimming to the surface of the lake they're from. It is unfortunately named Lake Titicaca.  https://animaldiversity.org/accounts/Telmatobius_culeus/

 

That's really interesting about the coral shape. The zoas are better at snagging food than I would have thought, evidently. 

 

I can't crochet, but I've done a bit of needle felting of corals. I'll try to find it for later.

That frog is actually cool. I'm googling it up to read more on it, but some sites list it as 'scrotum frog'.