Need help bad!!

[ktomminello]

My bc29 killed my blenny and puffer. I don't know how but even with my thermometer off and a quick reassurance that things were working fine (filter clean, back refugium in check, pump doing decent and water parameters well within spec). I noticed water was a little warmer than I like it so I checked everything, even removed and rinsed through my chaeto with pure ocean water (boxed water). Regardless of all of this I woke up today and my water was HOT HOT HOT and tragically my beloved duo didn't live through it..... I am relatively new to saltwater but this is the first time in over a year since I started that anything like this has happened. Does anyone know why this may have happened and what precautions I can take to make sure this doesn't happen to me again?

Please help me if you can- my biggest thanks in the world for any help I can get. I've been so busy building up for my freshwater biotope I haven't had much spare time to do research. I wouldn't ask if I didn't need the help. Thanks in advance for any insight or stories of similar woe and solutions that worked for you.

 

[Breakthecycle2]

Do you have a heater?

 

[ktomminello]

I do, but it was off and unplugged because it has been warm where I live and I noticed the water in the tank was warmer than I liked it to be, so it was the first thing I knocked off the list before the deaths even occurred.
I'm freaking out because I've never been through this before. This is my first biocube, I'm not sure if something with the cube malfunctioned or if there is a biological reason for this conundrum. All I know is I've only been saltwater aquarium keeping for just over a year and never experienced anything like this in my 40g open top fowlr and am desperately searching for an answer before I attempt to re start my cube and start over again

 

[ktomminello]

Does anyone have any input

 

[spoonman]

That has a pump in the back, right? It could be going bad and heating the water.

 

[ktomminello]

That's what I was thinking, I'm going to my lfs now and am going to see if I can 'Frankenstein' a better pump and new tubing.... Any thoughts on chillers? Thanks sooo much for your response.

Lol, and yes, it is the one with pump housing in the back

 

[Ingy]

What lights? Primary source of excess heat!