Mr. Saltwater Tank TV Friday AM Quick Tip #31: Fight the Swing!

Do this before you go to bed.

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Comments for this article (19)

  • Matt says:

    OK that’s a really simple, free and sensible tip… How well that’ll work with our kids running around is another story… lol Hmm… some mesh screen doors perhaps? Is that going to far?!? Is it possible to go to far in the pursuit of Reef Tank perfection??

    So this tip coupled with the open window tip may well go a long way towards avoiding the pH drop… Have you tried testing with one, both or without these methods to see how much difference there might be? Just an easy and interesting bit of free experimentation..

  • Jake says:

    the entire back side of my cabinet is open.. so leaving a door open will do nothing. Something like this may work for you Matt.

  • Mark says:

    Great tip! I also leave my door open when we leave town. I just make sure I have plenty of ato water.

  • The entire backside of my stand is open too. In order to get good airflow, the air has to come in and go out, opening the front doors allows for the flow to occur.

  • Jeff says:

    Why or how does this work? Thanks bud. You are doing a great job!

  • Jeff…it works by exchanging the stale air that is often high in CO2 with oxygen rich air. The high CO2 air drops your pH while the oxygen rich air raises it.

  • Joe cashwell says:

    Because I’m a ‘reef junkie’ and a gadget fanatic, I have a fan under my stand… I know, I might be going a tad too far, but hey, some one has to set the bar…

  • Edwin says:

    Nice Tip Mark. I also leave my canopy open at night too.
    Happy Friday!!

  • Jeff says:

    WOW! 13min. Response time. Gotta love it! Thanks Mark!!! Your answer makes complete sense. I have always figured in positive air flow ventilation into our installations. My thoughts of doing so revolved around combating the temperature of stale hot air from the open water, hot pump motors, and gadgets from collecting underneath and possibly effecting the structural integrity of the support stand down the road. Never thought about the additional benefit of the stabilization of pH .
    Thanks again.

  • Lucas says:

    Would it help to put an air pump hooked up to a bubble wand in the sump?

  • John bianco says:

    Hi mark , do you have any thoughts on the ecoxotic panorama led lighting , I want to buy led lighting for my aquarium and was told about these , (two of the 23.5 inch fixtures to go over my 48 inch tank

    Thank you


  • Lucas…an air pump can help but you have to make sure it is pulling in fresh air. If you pump CO2 laden air into your tank, it’ll drop your pH.

  • Joe…you definitely set the bar…high!

  • Matt..I open my stand up once my son goes down to sleep! Forget doing it when he is awake as he takes everything out that is under my tank!

    I’ve done both the open window/open stand test and the best result is leaving the windows open and the stand open. That lets the fresh air that is coming into the house flush out the air under the stand.

  • Matt says:

    Hmm I know what you mean… I wouldn’t have imagined my two year old could undo the pressurised lever on an external filter (after bypassing a child proof catch no less) but he seemingly did it with ease! That was an interesting mess!

    I have a strange vision of your lad running around with a sizeable skimmer under one arm (whilst covered in skimate) and a salifert test kit under the other with an intent look in his eye… It will happen you watch… trust me!

    130 gallon (that’s 500ltr’s / 108 UK Gallons for everyone else including me…lol )due hopefully next and I’ll be DIY’ing the cabinet so I can choose my sump size… I’ll build in some removable doors or the like as you’ve done Mark… Seems a good idea to have two choices for access rather than a titchy door or two…

  • Mad Hatter Reef says:

    Knowing My luck I would find the dog swimming in the refug in the morning 🙂

  • Larry says:

    Hey, love all your videos. My question is should I take the crushed coral out of my reef tank and put live sand .?. Please let me know. Thanks Larry……..

  • Brian Davis says:

    Mark, I’m curious what are your thoughts on what may be considered an acceptable diurnal pH swing tolerance for hard corals? My pH has a very steady progression and regression over the course of each day. My diurnal swing is religiously around .30; it begins at 0700 at pH of 7.93 (approx) and slowly and steadily rises to 8.23 by 1630 (10hrs!), from which time it reverses and slowly descends to pH of 7.96 over the following 7hrs. (The numbers are a close example to my average parameters). I understand the less swing the better, but what pH swing will most SPS animals tolerate? I assume this trend will improve as my fuge matures? Thanks for any enlightenments.



  • Brian…that’s a good question and everyone has their own beliefs. I am in the .25 – .30/day camp. That’s how much mine swings and everything looks great. I had issues with my tank when it swang more than .30/day

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