My Bettas Are Cold How Do I Add A Heater?

Sorry the title is weird. I have a divided 10 gallon with an aqueon pre-set heater. It's only reaching 72F but still cycling on and off. One of my betta look cold, his fins used to be really spread out but now he looks like he did that time I forget to plug in the heater after a WC. I bought an adjustable heater but I have NO idea how to add it. The preset is in the middle section, my thoughts were to put the heaters on each end. I'm worried that if I go from 72 to 78 I'll shock them. Should I set my adj. to like, 74, then the next day 76 until I reach 78-80ish? Also, am I better off buying a second adjustable in the future? I'm worried that if my adjustable is set to 82 for healing, my preset will turn off on the opposite side. The dividers are from lifewithpets and have holes in them for water flow, but with using 3 sponge filters, the flow is not very strong (because I own betta...). TIA guys!

 

Thank you to whoever moved my thread, hoping it helps me get answers!

 

Heaters typically heat the water up slow so set it to 80 and plug it in. It will probably be higher then your preset so I would just swap them.

 

I have two Betta’s in 10 gallons and used to have a divided one. I used two 50 watt heaters on either side and set them both to 78 as I feel that is the best temp for Betta’s. The heater itself will slowly raise water temp so you won’t have to worry about shocking them. 72 is very low and I wouldn’t be surprised if the one Betta has gotten fin rot. Do you have any pictures?

 

what else is in the tank? you may be able to get it to heat the water better if you move it over a sponge filter output, or over a air stone, or in front of the filter outflow, the idea being constant new water flow might still be cold enough to cause it to stay on.

 

If your tank is divided into 3 sections with holes only at one level (top, middle or bottom) on solid dividers, get 3 adjustable heaters, one for each section and set them each for about 78°-82°F. Warm water rises, sponge filters move water very slowly, and limited circulation between the compartments would definitely result in differences between compartment temperatures. Those temps could fluctuate throughout the day/night depending on outside (room) air temps.

 

Thanks everyone! Sorry I didn't reply, just got back to a computer. I added the heater and after 2 days the one who looked cold is spreading his tail and bottom fin again like he usually does and has been swimming in the middle-top instead of constantly being on the bottom. Temp is up to 78 and everyone seems happy. Again, thank you all.