Skimmer at A.M. or P.M.

[JD'sReef]

So I have read about this topic before, but I still have some questions. Since I have to much skimmer on my reef (using a ETSS - 600) on my 46 gallon tank. I am wanting to try something new, like to running my skimmer only one half of the day and see if the corals strive on the nutrients. With this said, most people say run the skimmer at night with the lights off. Thinking about that though, isn't more oxygen used during the day when the polyps are extended from my corals?
My light on the refugium runs at night as well to try and balance out the PH fluctuation.
I want the skimmer to help the PH stay more consistent when the lghts go out. Any ideas would be great please.
Thanks,
J.

 

[trido]

Why dont you just let the tank be fully saturated with O2 and skim real dry 24/7? I guess if I didnt have a choice, I would keep up alot of surface agitation and skim at night to help offset PH swings.

 

[Anonymous]

So I have read about this topic before, but I still have some questions. Since I have to much skimmer on my reef (using a ETSS - 600) on my 46 gallon tank. I am wanting to try something new, like to running my skimmer only one half of the day and see if the corals strive on the nutrients. With this said, most people say run the skimmer at night with the lights off. Thinking about that though, isn't more oxygen used during the day when the polyps are extended from my corals?

There is typically more dissolved oxygen in an aquarium during the day because the corals and algae make oxygen as a byproduct of photosynthesis. At night the corals and algae consume oxygen. In a well aerated and skimmed tank the dissolved oxygen level should be near saturation in both cases anyhow.

My light on the refugium runs at night as well to try and balance out the PH fluctuation.
I want the skimmer to help the PH stay more consistent when the lghts go out. Any ideas would be great please.
Thanks,
J.

If you want to keep your pH more consistent then consider dosing kalkwasser at night. Besides lots of other benefits it will raise your pH. If you don't have one already I would consider getting a good digital pH probe. You can track your pH and watch the effect kalkwasser has on your tank.

HTH,
Matt

 

[Anonymous]

Just run the skimmer 24/7, and dump half of the skimmate back to the tank whenever you clean your skimmer.... wait, that's a bad idea.

:lol:

Seriously, to keep the pH, you should run the skimmer all the time for good gas exchange.

 

[Anonymous]

Put me down for another vote for 24/7 running of the skimmer.

 

[ChrisRD]

I'd just leave it running 24/7 too...

 

[Anonymous]

24/7

 

[Anonymous]

If you want to keep your pH more consistent then consider dosing kalkwasser at night. Besides lots of other benefits it will raise your pH. If you don't have one already I would consider getting a good digital pH probe. You can track your pH and watch the effect kalkwasser has on your tank.

Chemistry Q, Mr Matt (or anyone else that can answer).
If the pH is risen at night, due to excess hydrogen ions, where do they go during the day?

 

[Anonymous]

If you want to keep your pH more consistent then consider dosing kalkwasser at night. Besides lots of other benefits it will raise your pH. If you don't have one already I would consider getting a good digital pH probe. You can track your pH and watch the effect kalkwasser has on your tank.

Chemistry Q, Mr Matt (or anyone else that can answer).
If the pH is risen at night, due to excess hydrogen ions, where do they go during the day?

There is typically more dissolved oxygen in an aquarium during the day because the corals and algae make oxygen as a byproduct of photosynthesis. At night the corals and algae consume oxygen. In a well aerated and skimmed tank the dissolved oxygen level should be near saturation in both cases anyhow.

Here is a good article that explains that idea and is (fairly) easy to read:

http://reefkeeping.com/issues/2007-05/rhf/index.php

 

[fedlund]

ph should become more acidic at night due to increase in co2 (as there is less photosythesis and more respiration). so there is an increase in carbonic acid (i think)

 

[JD'sReef]

If myskimmer is to big for the tank however, am I or am I not taking away nutrients from the corals? I have always had the skimmer on for 24/7, this is just something I was thinking about.
-PH goes down with the lights off; correct?
-PH goes up with the skimmer on; correct?
-A skimmer ment for a 100-300 galons is taking away from my corals in a 46 galon tank correct?
Not trying to sound cocky on those two statements, just trying to decipher what to do.
Thanks all,
J.

 

[Anonymous]

If myskimmer is to big for the tank however, am I or am I not taking away nutrients from the corals? I have always had the skimmer on for 24/7, this is just something I was thinking about.

Trying to understand your questions here. No, skimming takes excess nutrients-not necessarily what is useful as coral food. Don't take "nutrients" and "coral food" as being one and the same. It can strip out plankton/phyto, but that's not usually an issue. That stripping action has nothing to do with daily rise/fall of Ph.

-PH goes down with the lights off; correct?
-PH goes up with the skimmer on; correct?
-A skimmer ment for a 100-300 galons is taking away from my corals in a 46 galon tank correct?
Not trying to sound cocky on those two statements, just trying to decipher what to do.
Thanks all,
J.

Ph goes down at night because corals aren't photosynthsizing so CO2 goes up. Ph goes up when skimmer is running because the skimmer is putting dissolved O2 into the water and promoting gas exchange. The article link I posted explains the chem part of it far better than I can :lol:

 

[pcardone]

the skimmer is not to big for your tank, to think that it's over cleaning? skimming to me is natures toilet bowl. the more the better. alot of these guys have beautiful tanks 24-7

 

[JD'sReef]

Maybe I am looking into this way to deep. A gentalman at my LFS (who I trust) told me aboout this idea and my wheels began to spin. I guess leaving it runing 24/7 is not that bad of an issue. Better stated, "Not an issue".
Take care.
J.

 

[Anonymous]

If you want to keep your pH more consistent then consider dosing kalkwasser at night. Besides lots of other benefits it will raise your pH. If you don't have one already I would consider getting a good digital pH probe. You can track your pH and watch the effect kalkwasser has on your tank.

Chemistry Q, Mr Matt (or anyone else that can answer).
If the pH is risen at night, due to excess hydrogen ions, where do they go during the day?

The pH is lower at night. Good question, and I don't know. Get that Subcom or 7E in here.

 

[Anonymous]

If you want to keep your pH more consistent then consider dosing kalkwasser at night. Besides lots of other benefits it will raise your pH. If you don't have one already I would consider getting a good digital pH probe. You can track your pH and watch the effect kalkwasser has on your tank.

Chemistry Q, Mr Matt (or anyone else that can answer).
If the pH is risen at night, due to excess hydrogen ions, where do they go during the day?

The pH is lower at night. Good question, and I don't know. Get that Subcom or 7E in here.

the easy version is in the article I cited earlier, basically as CO2 is consumed by the critters during the day (CO2 = acidic) the Ph in the tank rises (becomes alkaline):

One of the first things that aquarists who measure pH notice is that the pH changes from day to night in coral reef aquaria. This diurnal (daily) change in pH in reef aquaria occurs because of the biological processes of photosynthesis and respiration. Photosynthesis is the process whereby organisms convert carbon dioxide and water into carbohydrate and oxygen. So there is a net consumption of carbon dioxide during the day. This causes many aquaria to become deficient in CO2 during the day, raising their pH.

Likewise, all organisms also carry out the process of respiration, which converts carbohydrates back into energy. In the net sense, it is the opposite of photosynthesis, producing carbon dioxide and reducing pH. This process is happening continuously in reef aquaria, but is most evident at night when photosynthesis is not pushing pH upward.

The net effect of these processes is that pH rises during the day and drops at night in most reef aquaria. This change varies from less than a tenth of a pH unit, to more than 0.5 pH units in typical aquaria. Complete aeration of the aquarium’s water will entirely prevent this diurnal pH swing, by driving out any excess carbon dioxide or absorbing carbon dioxide when deficient. In practice, equilibration of carbon dioxide by aeration is difficult, and this goal is not often attained. Consequently, the pH does change between day and night.

 

[Anonymous]

If you want to keep your pH more consistent then consider dosing kalkwasser at night. Besides lots of other benefits it will raise your pH. If you don't have one already I would consider getting a good digital pH probe. You can track your pH and watch the effect kalkwasser has on your tank.

Chemistry Q, Mr Matt (or anyone else that can answer).
If the pH is risen at night, due to excess hydrogen ions, where do they go during the day?

The pH is lower at night. Good question, and I don't know. Get that Subcom or 7E in here.

the easy version is in the article I cited earlier, basically as CO2 is consumed by the critters during the day (CO2 = acidic) the Ph in the tank rises (becomes alkaline):

One of the first things that aquarists who measure pH notice is that the pH changes from day to night in coral reef aquaria. This diurnal (daily) change in pH in reef aquaria occurs because of the biological processes of photosynthesis and respiration. Photosynthesis is the process whereby organisms convert carbon dioxide and water into carbohydrate and oxygen. So there is a net consumption of carbon dioxide during the day. This causes many aquaria to become deficient in CO2 during the day, raising their pH.

Likewise, all organisms also carry out the process of respiration, which converts carbohydrates back into energy. In the net sense, it is the opposite of photosynthesis, producing carbon dioxide and reducing pH. This process is happening continuously in reef aquaria, but is most evident at night when photosynthesis is not pushing pH upward.

The net effect of these processes is that pH rises during the day and drops at night in most reef aquaria. This change varies from less than a tenth of a pH unit, to more than 0.5 pH units in typical aquaria. Complete aeration of the aquarium’s water will entirely prevent this diurnal pH swing, by driving out any excess carbon dioxide or absorbing carbon dioxide when deficient. In practice, equilibration of carbon dioxide by aeration is difficult, and this goal is not often attained. Consequently, the pH does change between day and night.

Right, I get all that, but sfsu is asking specifically about H+ ions. pH is a measure of H+ ions. Obviously they do not disappear and reappear from the system every day/night fluctuation. When you add a base like kalkwasser (Ca++ and OH-) it's very clear what happens to raise the pH. The OH- ion steals an H+ ion to make H2O, thus reducing the number of H+ ions in solution. So how exactly does a higher concentration of CO2 = higher concentration of H+ ions?

I should have paid more attention in chemistry.

 

[Anonymous]

I should have taken chemistry in college, unfortunately I was scared off by the ex-navy seal (no kidding) instructor who quite frankly told us on the first day that we'll do an experiment of dropping copper in an acid and if we're not under a fume hood we will die and the two people next to us will die. Needless to say didn't want to deal with someone else screwing around with my life... that and he had this illegal rule of locking the doors during lecture even went so far to say "If you need to go to the bathroom make sure you really need to go, because once you leave you don't come back"

 

[brandonberry]

CO2 + H2O = H2CO3 (carbonic acid)

See this for all the other mumbo jumbo:
http://www.chem.usu.edu/~sbialkow/Class ... 0Acid.html

As for overskimming, no matter how much you skim, it is unlikely you will acheive lower nutrients than that found in a natural reef. If you are worried about not enough nutrients, add more fish. That always seemed to work for me. In a few tanks I've set up for people, I purposely put an oversize skimmer on the tank because I knew they would want more fish than what would typically be recommended for a tank the size they had.

 

[Anonymous]

CO2 + H2O = H2CO3 (carbonic acid)

And the H+ ions are more likely to "separate" from the H2CO3 molecule than they are from H2O, right?