Tank temp 84 help.

[Warpigdave]

I’m trying to find out why my 90 gallon tank temp is 84. My tank temp keeps setting off my thermostat alarm. I even unplugged my heaters. Here’s my setup. Glass lid with fluval marine and reef light. 24” doesn’t cover the entire tank length. 40 gallon sump. Icecap protein skimmer. Vectra s1 return pump. 57w uv sterilizer. I thought it was the sterilizer and unplugged it. Temp didn’t drop much. I can’t unplug my pump to see if that’s the cause because then my water won’t circulate. Ambient room temp is 70. I’m just worried that 84 is too high temp. And come summer the ambient room temp will just increase.

 

[BeanAnimal]

Short terms - fans blowing across water (not directly at) to drive evaporation. This will get you some relief.

How long has the tank been setup and what is the "normal" operating temperature.

UV will certainly heat the water and 57W is pretty big.

Lose the glass lid, that is preventing gas exchange, preventing heat escape and evaporation.

 

[Finn450]

I'd bet it's your heater(s) that are the problem. If possible remove that lid. keep circulation going. unplug your skimmer and UV for a few hours and see if the temp drops a few degrees. May want to consider replacing the heater with a quality 300w.

 

[Warpigdave]

I'd bet it's your heater(s) that are the problem. If possible remove that lid. keep circulation going. unplug your skimmer and UV for a few hours and see if the temp drops a few degrees. May want to consider replacing the heater with a quality 300w.

My heaters are unplugged. Tank has been setup 1 year. Always been warm. But now as temps warm it gets warmer. Unplugging uv only changed temp by 1 degree.

 

[BubblesandSqueak]

glass top isn't letting the heat out. mesh would be best.

 

[Malum Argenteum]

Have you double checked the temp with another thermometer (better, two others to break the tie)?

 

[Warpigdave]

Have you double checked the temp with another thermometer (better, two others to break the tie)?

Yes 2 other thermometers in different spots of the aquarium along the sand bed. Plus the thermostat. I’m guessing its the glass lids. I had a 125 before and didn’t have this problem, it had glass lids but the overflow box was outside the tank allowing maybe for evaporation. This tank is a corner overflow in the tank.I’m going to try meshing half the top.

 

[JNalley]

My heaters are unplugged. Tank has been setup 1 year. Always been warm. But now as temps warm it gets warmer. Unplugging uv only changed temp by 1 degree.

how long did you wait to see a result? It takes quite a while for 90 gallons of water to cool back down, it doesn't just plummet immediately.


Every electrical device in your system has a wattage rating, watts are what drive temperature (even in heaters) and it's a linear relationship between watts:BTU. What are the largest wattage items in your water?

 

[JNalley]

Also, 84 is not crazy high... surface temps in the Gulf of Mexico get into the high 80's low 90's. It's not ideal long-term, but a common way to combat Dino's is to rais tank temp up to 84 degrees for 2 weeks while you let a UV run and dose silicates. It's also a method I have used on more than one occasion with great success this was performed with corals in tank as well as fish, cuc, and other critters... So don't get worried in the short term...