by TFH Magazine on January 19, 2011 at 10:56 am
By Mike Hellweg
One of the unexpected problems that I encountered during this year-long contest was temperature control in the fishroom. My fishroom has been up and running for nearly 15 years, so this year’s temperature fluctuations in the summer were a bit of a surprise. When I built my fishroom in the mid-1990s, building code required that I seal the room with thick plastic on the inside of the insulation before installing wall board. This created a nice, warm box which is perfect for fish for most of the year, and it keeps humidity in the room from escaping to the rest of the house.
The bare concrete floor serves as a heat sink that helps hold heat in the fishroom, slowly releasing it in the cooler evenings to keep temperatures fairly constant. I have the room on our home’s central air and heating system, which also helps to maintain a fairly constant temperature in the upper 70s throughout the year, except during the heat of summer, when temperatures may creep up into the 80s for a few days during hot spells.
This past summer was just a bit warmer than normal—okay, it was a good ole’ fashioned three-H (hazy, hot, and humid) St. Louis summer. We experienced temperatures in the 90s or low 100s for much of the summer, with an average temperature about 5° above normal. This, coupled with the fact that it did not cool off too much in the evening, allowed heat to slowly accumulate in my fishroom in spite of air conditioning. Some days even the cold water coming out of the tap was in the mid-80s! By the end of July, temperatures in my fishroom were in the mid-80s, and the upper row of tanks had reached 85°. There were a few days in early August when temperatures in the upper tanks got up near 90. The apistos and a few bubblenest building anabantoids absolutely loved it, and fry grew quickly, but most of the fish just sat and looked at each other for several weeks during the height of the heat spell. It wasn’t until late August that things finally cooled off and the fish started thinking about spawning again.
Another problem could have been humidity, which would make everything worse as far as I was concerned, but I addressed that problem during construction so humidity would not come back to haunt me. As I researched my construction plan, I heard horror stories about mold traveling all over the house from a poorly constructed fishroom. I was determined not to deal with mold. This was before we knew that mold was also a hazard to health, so as the character Barney Fife would say, I “nipped it in the bud.”
First off, I built my fishroom walls an inch away from the outside walls to allow a path for air circulation around the fishroom. To control insects that might find this area comfy, I covered the floor of this airway and the edges of the foundation above it with a layer of diatomaceous earth. The boards themselves were treated with a solution of boric acid. The sill around the fishroom is up off the concrete, separated by specialized sill insulation, and I sealed around the baseboards with clear silicone caulk to keep any water spills in the fishroom. So far this has worked well.
After insulating the room walls and ceiling, I installed the vapor barrier and the wall board. For the ceiling I added an insulated drop ceiling designed for wet locations—it is essentially a thick, rigid fiberglass board with an acoustic, water resistant cover on the inside. This has worked exceptionally well for both sound insulation and temperature insulation. When I’m working in my fishroom it is nice and relaxingly quiet. I can’t even hear the phone ring! All of the tanks are covered to slow evaporation and control humidity further.
I installed a simple bath fan designed to move the entire volume of air in my fishroom every four minutes. This is controlled by a humidistat set to 50 percent humidity. Mold grows above 55 percent humidity, so this has kept the room comfortable and mold free for 15 plus years.
It pumps the air outside via a dryer vent, and a couple of years ago I added an extra nylon (metal can rust) damper to the exhaust vent line to keep cold air from backing up into the fishroom during a power outage. The fishroom door has a slightly larger opening underneath, and one above that allow for fresh air from the rest of the house to be drawn into the fishroom when the fan is running. A nice, simple design that keeps humidity under control, but even with air conditioning it can’t quite control the heat when there is just too darn much of it during the heat of summer. I’ll keep working on that…