Heating Divided Tank?


Hallo guys!

I hope this is the right place to post!

I've just received a 60cm long x 30cm wide x 30cm tall tank (I think that's a 24x24x12" 15 gal?)

I'm planning on doing a 3 way divided betta tank with it (planted, maybe some nerites, tiger shrimp? - how lucky do I feel?-), probably using the DIY binder spines + that plastic cross stitch stuff for the dividers, or something similar, maybe opaque vinyl sheets or thick pieces of black sponge, something along those lines. I've got 3 sponge filters on order to run off one pump and I'm deciding on which light I'll use to stretch the length of the tank but I'm stuck on the heater situation.

My options are:
1) use a 50W (or 25W) heater in each compartment
Pros: I won't have to worry about water flow between each compartment = less chance of disease outbreak affecting all fish, it seems a neater option to me all round, all the bettas get ideal temps
Cons: I'm fretting about my elec bill already, it'll take up 3 separate elec sockets, I'd have to buy another two 50W heaters (or 3 25W heaters if I can get them, would that even be enough?)

2) Use two 50w heaters in each end compartment
Pros: Less sockets used, I'd only need to buy 1 extra heater, only use 2 sockets, less power usage, more chance of the compartments heating evenly?, with water flow between compartments I'd get more stable water parameters
Cons: Still fretting about the elec bill, still taking up 2 sockets, I'd worry that the compartments weren't heating up evenly, would that be enough wattage to heat the tank, I'd need to make sure the water flow was decent between compartments losing the advantage of containing disease

3) Use one 100W (or more?) heater in the middle compartment
Pros: Utilise just one socket, water flow between compartments would give me more stable water params, tanks would look less cluttered?
Cons: Leccy bill! I'd worry that the compartments on either end were too cold and the middle one too hot, I'd worry it would be too much wattage (or not enough? should it be 150W on a 15gal?), a 100W may not fight in the middle compartment comfortably, I'd have to buy another 100W

I've tried looking into an undertank heating system but I haven't found anything that hasn't led me to believe the tank wouldn't a) crack, b) explode or c) turn my aquarium into fish soup so I've gone off that idea. I considered fitting the dividers around the heater for all of three seconds but mental s of Betta Carnage: The Last Bloodletting, Part 3 turned me off that idea quickly too.

I'd love any input/help I could get from you knowledgable peeps, as always, I bow to your collective wisdom


EDITE I've had another idea, would this work?

I was thinking of putting a heater along the back of the tank (a 150W maybe?) with a divider from end to end along the length to heat the whole tank, then adding the dividers to section off the tank into 3 compartments as usual. Can anyone see any immediate problems with that?

Thanks again!


Hello! I personally would divide the tank 2 ways, instead of 3. I also would use a divider with flow but a divider that makes it hard 4 the bettas to see each other. If u r trying to avoid disease in between each division u would have to have a divider that was sealed water tight and use different equipment (nets, gravel vac, algae sponges etc) treating them like 3 separate tanks. The heater all depends on the amount of flow between each division. If there is going to be water flow I think a heater rated for a 20 gallon in the middle compartment (if doing 3) will work just fine. If u end up doing 2 with adequate flow through the division I recommend putting the heater beside the filter so it can more efficiently push out the heated water. If you are going to divide the tank 3 different ways with no flow between enclosures I recommend getting a heater for each enclosure rated for a 5g.


If you heat the middle tank the two beside it should be kept pretty close to the same temp, maybe a few degrees cooler, especially if you use thin glass dividers. But a heater in each partition would be best, end compartments second best.

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