Mr. Saltwater Tank TV Friday Am Quick Tip #78: Deep Freeze Me Just In Case


When things heat up, use one of these.  Just make sure you set it up ahead of time!

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Comments for this article (32)

  • Mark H says:

    Mark, good tip. I spend a few summers in N.C. and I used 1 gallon milk jugs during an emergency chiller issue.

  • Matt says:

    Good trick … Here in the UK I have doubts will need it at the rate the weather is going but good to know all the same 😀

    Thanks David and thank you Mark for bringing us our weekly quick tip fix… 😉

  • Ryan Ghering says:

    Great tip I used it last year many time.. However please remember to remove the labels, some inks and glues used in the labels are toxic to marine life.

  • Jesse says:

    Zip lock bags or even reusing the bags your fish and corals come in with ice cubes works great also! Great tip!

  • Gene says:

    I have being doing it for years since my basement is so hot in the summer but thanks For the tip or freezer bags with ro water and throw them in my sump the zip line ones

  • Matt says:

    Why ro water?

  • Chris says:

    I used 2 liter bottles. 2 of them will lower my 90 gallon 5 degrees. Great tip though.

  • James Giese says:

    i had the same question, why RO? I am all about 0 TDS in all of my water changes but people get way too finicky about never a drop of tap water in the tank.

  • Jordan says:

    Why use RODI water? There is probably zero chance of water leaking from the bottle.

  • Matt, James & Jordan…using RO is an overkill safety step just in case the bottle breaks or cracks. I’ll readily admit that the small amount of tap water that could get into your tank probably wouldn’t cause issues At the same time, I’d rather take an extra moment and fill it with RO water just in case.

  • randy says:

    I’m glad that RO water was mentioned. It’s always good to give it a mention. Too many people do not use it. The more times they hear RO water, the more likely they’ll get curious and do the right thing.

    Also: bottle could crack.

  • Kevin Bias says:

    Ugh… It’s supposed to be 100 degrees F here in Az today. I don’t think I will be getting outside any time soon…

  • James says:

    My point is, if one water bottle of tap water spills entirly in the tank, so what? Bfd. What would happen? Nothing. If you have your filtration setup up properly then a little but of tap now and again should be a non issue.

  • Koen Alberts says:

    I like the tip dude! So we in Holland say, dank je wel! (thanks)

  • Kim Phillips says:

    Thanks for the tip. This week in L.A it’s in the 80’s. I just put my bottles in the freezer. Great tip!

  • Linda says:

    Nice tip. Gonna get up to 100 in AZ this weekend. Here comes summer…

  • Edward says:

    great reminder, things are startin to heat up. Ladies and gentlemen start your freezing. Also good point about the RO water. sure for 99.9999 percent of people reading this a little tap water is not an issue. But lets pretend someone reading this has a hob power filter. Lets also pretend the tap water for whatever reason that day has a lot of chlorine in it. Bottle leaks, water containing chlorine finds its way into the power filter and onto the good bacteria. Could mean a restarted cycle. True not a likely senario. However please remember Mark is responsiable for giving information on the care of living things. If he did not always take the most cautious approach it could mean trouble for a living being. Also we’ve all been so careful to not introduce harmful chemistry into our tanks, why risk adding even a small amount through laziness.

  • John says:

    Thank you for your help. If you use ice from Food Store or other place where you get ice bags from you do not know what in the water.

    Other tip if that happens turn off most of the LIGHTS. As only use to the lights that can keep the corals going if you have Reef tank.

    Look in to backup fan as box fan or other fan open the doors to the sump and turn it on.

  • Jordan says:

    I do like this idea very much! I haven’t had as much issues with my tank rising too high but glad I can do something if needed.

  • Cheryl says:

    Great tip Mark, I also like the bag from the lps that you bring home your goodies in…

  • David says:

    thanx everyone for ur kind words and thank you Mark for putting my idea in ur friday morning quick tip I have a few tanks but a 1 litre bottle of icy water takes my temperature go down about 3-5 degrees in my (sexy tank) 100 litre, thanx again to everyone!

  • CRUXTON01 says:

    Hello mark and everyone. Here in the uk it dont get too hot but still thank for all your other friday tips.I would like to say thanks to Mark and to everyone who makes helpful coments on this website. Without this website I would have left the hobbie about a week in. I had no idea when I 1st started, stores over here just think about the money. But thanks to you guys i have a great little tank and we are hoping to go bigger later this year. THANK YOU

  • Ron says:

    James, You should check your attitude before checking the water.

  • James says:

    Take it easy Ron, no disrespect to mark. He provides great insight and knowledge to us every day and I thank him for it. I just think that it’s never wrong to question and always good to stir up a good discussion.

  • Gil says:

    Great tip! I had to do this myself recently on some 97 degree days here in Ct. A/C went out, and with my halides and fans temp was creeping pretty high. But with ice and good water circulation my reefy friends made it through unscathed. I didn’t use ro water, but agree its worth mentioning. Every tank and their caretaker is different. All tap water is different. Plus not everyone has a media reactor. Thanks again Mark!

  • Gil says:

    Also, I try not to let my tanks cool back down too quickly. I actually turned on my halides to slow the drop from 87 degree f. ( yes that’s w ice) Once the ac was fixed. Didn’t lose anyone but had a very full skimmer! Don’t want to shock ur inverts on the way up or down.

  • Raphael says:

    I have used this technique (ZipLock bag variation) myself, but, admittedly only in a Biocube 29 HQI, in which it took AWHILE for the ice to make a 2-degree dent in the rising temperature of my minuscule saltwater volume. Every bit helps, so I’d not discourage use of ice, but I recommend at least making one additional experiment (it worked for me): Buy an el-cheapo fan (or fans) and surround your equipment with good airflow. Ensure that whatever home air-conditioning you have keeps the temps surrounding your tank reasonably low. It’s far easier to exchange heat into 74 degrees ambient than 80 degrees ambient! Don’t let your tank area become a hot spot (compared to the rest of the house). That’s a sure sign that you’re not efficiently cooling the water.

  • david says:

    the one thing to remember is this will effect your ATO when you displace the water volume with the bottle

  • BobbyReef says:

    your the man Marky Mark

  • Jon says:

    I once let my 8 gallon biocube get up to 90°F overnight, when I didn’t notice that a snail jammed the recirculating pump. I unplugged the busted pump, hooked up an aquaclear 50 to the side to improve water circulation/maximize evaporative cooling, and threw in a couple RODI ice cubes to make up for the water lost to evaporation. Everything survived.

  • Mark F says:

    You’d really have to clean off all the glue and label from the bottle, instead, I just use a ziplock bag or fish bag and fill it with ice, ice pack or whatever I’m defrosting for dinner (just kidding, although not a bad idea) and that seems to do the trick. Although in my 225 gallons of water, it seems I can only maintain the temp, it’s really hard to lower it significantly.

  • sundar says:

    really..thanks for you tip bro..u rock…i fallow ur tips..try to visit inida..i have lot to ask…and u have a place to stay here…welcome to india

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