Unstable temperatures in 125Gallon tank

[jmadden93]

Hi all,

I'm new to salt water tanks, and I've been running a non reef tank salt water tank. My temps seem to fluctuate way too much during a 24hr period. From 74 degrees during the day (when you think it would be higher), and 84 degrees at other times (even in the morning when you think it would be colder since the lights have been off for 8hrs). I run my lights for 8hrs a day. They are powercompacts (right now only 1 34" 10k, and a 18" 10k). I'm getting a set of 4x 34" lights soon (2x 10ks, 2x atinics) and i'm worried this will make the issue worse. I've only got 2x hydor koralia 4 power heads in the tank and one return pump in my sump.

Is a 74-84 degree swing in 24 hrs common? I'm worried my fish will get ich or just die. Any solution other than to spend $$ on a chiller? Any things I can check or try?

Thanks in advance!

[LAReefs]

A 10 degree swing is not common. Solving low temps is an easy fix by adding another small heater. However, the 84 degree high is borderline dangerous. Furthermore, because it is in the morning I would check your heater and make sure it is functioning correctly before adding a new one. It's very strange for a tank to be 84 degrees in the morning.

[jmadden93]

Thanks for the reply... I have two 400w heaters (hydor thor 400w series).
I guess I can try running the tank off just one at a time and see if one of them is problematic. If you have any other suggestions I'd appreciate it. Thanks for the tip!

[dkh0331]

My tank stays right at the 80 degree range. I have two 500W titanium Finnex heaters and a couple of clip on fans blowing on my sump, both connected to a two stage Ranco controller - https://diyreef.authsecure.com/shop/...roducts_id=212

[jmadden93]

Turns out it was a bad 2nd heater. Thanks guys! I've got it stable at 77 degrees now!