Our missing sump and paperweight chiller are normally sore spots, but I will give you a break because you are joining in from so far away.
Welcome!
Peter's fail-safe plan for the chiller was to have a spare on hand in case it died. My predecessor ended up purchasing the back up from another vendor so it doesn't fit anyway
The next calamity of errors we experienced is the ambient heat thrown from the compressor exceeds the cooling of the heat exchanger. We have a very well built Aqua-Logic 1HP unit, but it is located in the small fish room and it is not directly vented. When I gave it a test run, the room went up 13˚F and the tank dropped 1˚F in about 30 minutes. It may have gone either way if I had left it, but the MARS holding systems would have been cooked in the process and some of the equipment may have overheated. We are going to run another test today, now that we ironed out some of our venting issues. My prediction is the chiller will be moved outside in the long run.
I'm with you on the air conditioning idea. In my 23 years professionally installing marine tanks, I have never used a chiller, or had use for one. I have used them on goldfish and lobster tanks and commercial systems, but never on a tropical reef tank.
Our current issue is temperature fluctuation. We are fighting against a few variable which include, but are not limited to...
- Seasonal changes (up here in Canada you can feel them).
- Radiant floor heating in the display tank area.
- Forced air gas furnace in the display tank area.
- Air conditioning in the display tank area.
- Air conditioning in the fish/filtration room.
- Lighting changes over the tank, including periodic lights out to combat nuisance algae.
- Exhaust fan that blows hot air from above the tank into the fish room. This creates negative pressure in the tank canopy, and positive pressure in the fish room. The humidity is drawn out of the living area of the home by the fan, and pushed back into it by the same fan through positive pressure.
- We have an HRV (heat exchanger) that was set wrong for the first few months.
- New equipment and more electricity (read as "heat") being added on a regular basis.
- mr.wilson forgetting to shut the fish room door.
- Playing around with the exhaust fan and forgetting to turn it back on.
Each of these effects the other, so we need to rein it in soon. The tank is running very cool between 76-79, which is too great of a swing. In my opinion that is too low. I would aim for 80-82; Let's call it 81˚F which leaves room for an upward and downward swing, matches the natural environment, and increases coral growth rates (compared to cooler waters).
I have three 1,000 watt titanium heaters ready to go. I will probably install them soon, as we cannot reach stability with our current environmental control system. The trend will be for the tank to run too cool, not too hot, so the chiller itself is a fail-safe (once we relocate it).
Back to the chiller and heat control. I recommend a dedicated heater and chiller controller by Renco. They are reliable industrial units that are very accurate. Since both heating and cooling is governed by one "brain", you will not have your heaters and chiller/air conditioning come on at the same time or in succession (one working against the other). The chiller I inherited with the project came with a single phase Renco controller, which I will upgrade to the dual phase to control the three heaters. I looked into running the heaters with the Profilux controller, but it was cost prohibitive due to the high wattage. It was also going to add a lot of clutter with an octopus of wires.
Sometimes an all-in-one unit is simple, while other times it is too complex and you end up with all of your eggs in one basket. Aquarium controllers are good for controlling some things, while giving a second opinion by simply monitoring others. That's where your fail-safe lies. We have an automated email and text message system if the tank temperature drifts to far out of the target number. That will come on line when we get the sump that I'm not talking about
In general, aquarium cooling is best dealt with venting hot air up out of the top with fans or vent placement. Cold air intakes should be placed at the floor where it is cooler. Pointing a circulation fan straight down at the sump will give enough evaporative cooling for just about any application.
If your ambient room temp is too high, which may be the case in South Africa, then a chiller makes more sense, but you might as well cool the air you live in at the same time because it costs about the same, and often less.
New lighting options like LED lighting and DC pumps are assisting in the cooling game. Buy stock in titanium heaters, as we will all be using them again. Its about stability more than target temperature. If you know your tank will have a tendency to drift hotter, keep the resting temp at 82˚F so a 4˚F increase will have no ill effects. Running the tank at 76˚F will only buy you a few hours at the cost of shocking your corals with an extra 6˚F increase when it overheats.
