surface agitation & gas exchange

[Tonto]

Hello,
I’ve been lurking for a while and I finally registered.
I would like to say that I have found this site, and others that are similar, very informative, & helpful.
It is nice to find a place that offers so much advise, experience, direction, and patience. Thank you!

Now for a simple question about surface agitation & gas exchange.
Does the surface of the water need to be broken like when a bubble rises to the surface and pops, or like when a stream of water that is falling to the surface?
Or does a return or P/H directed to the surface from below that makes a bump, rise, or ripple in the surface without actually “splashing” enough to get the job done?

I hope I am wording making my question clear enough for someone to actually know what I’m talking about.

Thanks

[SAT]

Some gas exchange will occur whether you break the surface or not. However, if nothing breaks the surface you'll develop an oily film, which may slow down the exchange. Also, you get a larger effective exchange area on an agitated surface than a smooth one.

[asmith]

Welcome to The Reef Tank! A powerhead or return should be fine for gas exchange. If your sump is like mine, the water is quite turbulent. I am sure that your skimmer (if you have one) will also help.

Andrew

[Tonto]

If your sump is like mine, the water is quite turbulent. I am sure that your skimmer (if you have one) will also help.

I have no sump or skimmer.
I have a 30 hex, up for 2-3 years
LR & DSB 3-4”
A Canister filter (fluval 304)
Maybe the worlds only working Power Sweep
A little cheesy pump.
Domino (1)
Trigger “Rhinecanthus rectangulus” (1)


I took an air pump out because I was tired of cleaning salt off every thing from the splash.
The P/H is near the surface but doesn’t break the surface.
The return from the can. I adjust so it falls into the water but it is a bit loud and I put it below the surface when I’m at home.
Between the Can., the P/H & the little pump the surface of the water is always rippling but I want to know if that is enough agitation to do it’s thing.

Thanks for the replies.

[Spanky]

Hi Tonto, WELCOME
glad you decided to join in.

Think of it this way. What you want to try to accomplish is to roll the water from the bottom of the tank to the surface, having as much new water exposed to the surface as often as you can. A air stone, powerhead, filter, etc can all be used to do that. One way to tell if you don't have enough circulation is to check your Ph first thing in the morning before lights on. If your Ph is low, or fluctuated a lot from the afternoon before (lights on), you need to blow off more CO2 and you don't have enough circulation.

HTH
Spanks

[Tonto]

I have a dark secret.
I have never tested my water.
OOOOOOOOOOHHHH. Gasp, Whisper, chuckle.
So I have no idea about the PH.
I also (until I started lurking) used tap water.
I know, I know.
I am learning. I started using clean water the last 2-3 months and I can tell a difference already.

When $ permits I will be setting up a real tank. I have had a Salt-water tank up for the most part of ten years.
I have learned a lot & am not afraid to admit I have a lot left to learn.
I found the local club (SCMAS), attended a meeting, joining at the next.
I have an inside scoop on a 120 AGA that I will set in the corner for a year or two while I acquire the rest of the stuff.
The next two things on my list are a test kit & RO/DI.

I have just been really curious about the “agitation & gas exchange” thing lately.

[Spanky]

LOL stick around, we all have dark secrets! Have you met Horge yet?

Anywho, when in doubt more is better as far as circulation.

[Flatlander]

Spankys suggestions, echo Sprungs on his plenum article. Powerheads breaking the water near the top, were no match for powerheads or airstones, creating an upswell from the bottom to the top. Of course the best is surface skimming, overflows & skimmers, to create oxygen and exchange.

Here is a good example. Recently I had my sump down for a day or so, while doing some new pump work. My ph normally runs at 8.1 at its lowest. That night, without the sump, overflows & skimmer, { I did have 8 powerheads running in the tank, PLUS, my turf scrubber}, the ph dropped to 7.8 by the morning. All the next day, even with 1200 watts of halides on, it never climbed over 7.97.

[Tonto]

Thanks for the reply.

I think I’m going to go home tonight and rearrange the flow.
I just moved a couple weeks ago so things aren’t just right yet.

[MargaritaMan]

I could loan you my two year old. She loves to stick her hands in the tank and splash around. And yes I let her do it. MM

[Tonto]

I have a 6-year-old that is really starting to get into the little things in the tank like the critters & the worms in the sand and look past the fish.
That was a smooth attempt at disguising a babysitting job as a piece of tank equipment. You almost had me.

[Spanky]

were no match for powerheads or airstones, creating an upswell from the bottom to the top.

Si Senor

We have large storage vats for NSW and can maintain the Ph without buffers simply by rolling the water from the bottom to the top.

Spanks