Finnex heaters maintaining temps

[19frank90]

I filled a Reefer 425XL yesterday and have a 300W Finnex titanium heater currently in the sump. The heater ran for about 12 hours in the display while it was filling and has been running in the sump the last 14-16 hours. I originally had it set at 76 and it stayed pretty consistent at 71.6 on my thermometer. I bumped it up to 78 or 79 on the controller. It's currently steady at 73.2. Is it common for the discrepancy or am I just being impatient with it getting up to temperature?

For what it's worth, I have a Cobalt Neo-therm in my Biocube 29 that's set at 76 and stays at 76.3 on the thermometer.

 

[tripdad]

Mines off by 1.5 degrees but dead consistent.

 

[The Aquatic Arsenal]

I have one in a sump of a 420 gallon fish system with a ReefLite and temp probe. It stays pretty consistent at 81°F.

 

[Quietman]

Yours seems consistent - 4 to 5F lower than setting on that thermometer. I wouldn't make a call an what's what until you get a few thermometers (or a high accuracy themometer). They are notoriously inaccurate but are usually consistently inaccurate, meaning they may be 4 degrees off but they'll stay 4 degrees throughout range of reef temps.

 

[S.Pepper]

I agree with others. My Finnex 300 watt heater shows it's at 80 degrees when the temp is actually about 78 degrees; but it does keep it consistent.

 

[homer1475]

Are we talking the heating rods, or the ones with their own thermostat?

I have the 300W heating rod(no thermostat), and it keeps my tank well within .5 degrees of it's set temp.

 

[MTBake]

No issues with my finnex maintaining temp. I did add a second 300 watt to my reefer xl 525. One heater just wasn't enough to keep up. It ran constantly and wouldn't get past 74.5 degrees. My tank is in my 68 degree basement though.

 

[flagg37]

I have two 200w finnex heaters and both are set to 80 on their thermostats but I have my apex control them. It turns them on at 77 and off at 78. If for some reason the apex gets stuck with them on, then their internal thermostat will turn them off at 80 which if I recall correctly is actually 79 according to the apex.

 

[19frank90]

Wondering now if I should've went with the 500W. The 300 is rated for 80-100 gallons and the 500 is rated for 100-120 gallons. The DT is 88 gallons but with the sump and everything its 112.

 

[MTBake]

I used 2 smaller heaters for my system. My thought is that if one gets stuck on, it shouldn't be able to cook my tank by itself. Got a Ranco on the way to control them for redundancy.