SIZING the Chiller: Our 300 gallon aquarium reef tank is kept at a temperature between 75 and 79 degrees Fahrenheit . Your specs say a 1HP only cools a 260 gallon tank (at 59 degrees), and you therefore recommend a 2 or 3 HP Chiller. I believe a 1 HP-220V chiller would be more than adequate if we want to maintain the temperature at 75 to 79 F. Am I correct or not understanding something about sizing. Is the 1 HP model the correct one to purchase for my needs? – Commercial Chillers specs say 260 gallons for running a cold water environment. For your desired temp requirements(tropical) – a 1hp is more than capable. In fact I would even say a 1/2hp would do the trick. But depending on enviroments – ambient temps, equipment – 1/2hp is on the border. When you are almost at the cut off - I always recommend to one size higher. Here is a link to our chiller sizing calculator. - http://jbjlighting.com/temperature/chillerSize.php
2) TEMP CONTROL: Is the temp control sensor internal to the unit and not an additional part that has to be purchased.
The temp probe is internal – built into to the heat exchanger.
3) 220 V unit: Does the unit come with a standard plug or does it have to be specially wired to match the receptacle?
The 220V unit does not come with a plug – you can get these at any hardware store. Washer/Dryer 220v plug will be fine.
4) CONNECTIONS: Are all the connections and hosing included with the unit (excluding the connections to the pump)? Is there a max distance the chiller can be from the sump box?
You will receive all the 2 compression fittings to plumb the chiller. There is not a max distance the chiller can be from the sump. As long as your pump can push the minimum flow rate to and from the chiller you should be fine.