4qty of jager 100w heaters on a ranco or secondary control system such as an apex or other for your 200G setup. I generally try to target a minimum of 2w of heater per 1g of water, but at most, I would target 3W per 1g of water in which you would need 4qty of 150w jagers.
- Set the heaters themselves to turn off at the maximum temp you will allow in the system, say 81F.
- Next, set your controller to turn on the heaters at the lowest temp you will allow, generally 74-78 depending on your reef keeping beliefs. Also set the controller spread to 1F maximum difference for power savings.
- Last, buy a separate digital thermometer with temperature alarm or at bare minimum, setup your controller to alert you via email that your tanks temp is critically high or low.
With this type of setup, you benefit from redundancy and fail safes such as....
- if a heaters built in thermostat fails and sticks on, then the controller will act as the fail safe and shut down all the heaters properly so nothing cooks.
- if the controller fails and sticks on, your heaters built in thermostats will kick the heaters off and you will not cook your tank.
- If the insane happened, and your controller was to stick on, the chances of more than 1 jager sticking on at the same time is very, very slim as they are as rock solid of a heater as you can buy period. However since you have divided the heating among 4 heaters, you will not cook the tank if the controller + 1 of the heaters was to stick on. If more than one did stick on, buy a lottery ticket and be relieved the temp alarm you purchased alerted you to the problem before anything dies.
- with multiple heaters, if one decides to fail totally and not function, the other units will keep the tank from going ice age. And if the insane happened in this scenario and more than one died, then the temp alarm would alert you that the temp in the tank was critically low.
- If the controllers thermometer dies, then your separate temp alarm will alert you of the danger.
It sounds crazy expensive, but 4qty of 100w jagers will set you back about $80 and a separate controller such as a ranco etc-111000 will set you back about $55. A digital thermometer with temp alarms, maybe $30. Basically the cost of a few nice fish or a few nice corals which is dirt cheap insurance. And if you already have a reef controller like an apex or other, then it comes out even cheaper!
If you read around, the majority of the salts on here will not use a titanium heater... wan bros.. finnex or anything like that and the majority will recommend jager heaters for a reason. Also many of us would never trust our systems to a single heater that does not have an internal thermostat so you can setup the fail-safes like I mentioned with a controller. However many do not run this elaborate of a setup and they get along fine or have so far, but for my system, I would not run it any other way. Good luck!