cooling tank

Question
hi shawn
well its summer now, and really hot in the prairie. i have a bit of a silly question. my tank is sitting at 81 degrees, and air conditioning just isn't cooling the tank water. whats a safe way to cool off my tank. its too hot for my sharks.
thanks
dean

Answer
Hello Dean
Summer heat waves can be a real issue with tanks - specially with marine ones where livestock is more sensitive to temperature swings. There are a couple of things that can be done assuming you aren't in the market for a chiller...
1) the frozen soda bottle method - take an old soda bottle- size depends on your tank and how many degrees you want to cool it down by. I'd start with those 600ml bottles if you don't have a huge tank - fill it with tank water and freeze it. When your tank is starts to spike, drop the bottle in and check the temperature periodically (till you figure out the "right" size - takes a couple of attempts)- just don't start with a very large bottle and keep checking on the temperature till you find out how big a bottle it takes.
2) breeze on the water method - flip open your lids and cover the top with nylon mesh, then get one of those desk fans and set it up to blow across the water surface. You will also need a good air pump for this method or a power head to create water turnover.
ADDITIONALLY
1) make sure there isn't any direct sunlight getting at your tank
2) keep the curtains drawn in the room with your tank if you can - ambient temp does make a difference
3) if you don't have a good air pump, it may be an idea to get one - dissolved oxygen levels are far lower at higher temps, so this way you can get some extra oxygen from the increased surface turbulence.
Hope that helps; feel free to ask any further questions you may have.