I recently set up a 10 gallon tank with dividers, my dad suggested i get a filter for one side and put the heater on the opposite side, this however dosent work, so i thought i'd move the filter to the middle to see if it made a difference, it did a little bit. The problem is the filter has to strong of a flow and the heat isnt being distributed evenly.
I introduced the fish to it to see how they would react, the one on the right side with the heater just flares at his reflection, the one in the middle with the filter weaves back and forth across the glass in the front when he stops moving the current moves him around, the one on the left side clamps his fins up and stays in one spot, i moved them back out so i can work on the tank if i need to change things.
I thought of going with my original plan of having an air stone in each compartment with the heater in the middle, would this work? or might you have any other suggestions?
I think three airstones would only be more bothersome to the bettas. I also think a 10 gallon tank is too small to be having such circulation issues. What kind of dividers are you using, and how well do they allow water to pass through them? What are your temperature readings in each of the sections? They don't have to be equal as long as all three fall somewhere between 78ºF - 82ºF, right? That is, assuming there aren't any 'inter-sectional' fluctuations, or something. I don't know how stable your prior setup's readings were, just that you mentioned they were different between the divisions.
In any case, it would make the most sense to me to have the heater in the middle instead of the filter, which I would consider second priority. Also, I wouldn't expect your fish to react in the same way after being relocated to a new environment. They will each be effected differently, I'm sure, and may just need a week or two to adjust. What I mean is: your bettas probably won't appear normal after the relocation, and may come off looking ill and sickly. This is a common occurrence and may have nothing to do with your tank's supposed problematic setup, you know?
As for your filter issue, you should probably baffle it as soon as you're able. Water currents are very stressful to bettas as they prefer stagnant conditions. I believe there is a sticky in the 'Bowls, Habitats, and Accessories' section that covers the construction of one.
The dividers i am using are canvas mesh, the water can get through them easily. My two thermometers read as 80 in the compartment with the heater and 75 -73 in the compartments without it, prior to this tank they lived in seperate small containers, in all 3 the temp was about 76 without heaters or filters.
I only got them a new tank because they didnt have enough space and the fact that during winter it gets very cold in our house (i've only had my bettas for a couple months) and i was worried about the temp dropping to low.
How well can heat be distributed if the water isnt moving? As i understood there has to be some sort of current to get the water to move to distribute the heat evenly, maybe im wrong?
I hope the new changes work out for both you and your fish. Also, I didn't mean to denounce airstones entirely. It's just that from my experience on these forums I've come to learn that they're not the best tank addition for bettas. That's not to say, though, that they can't be added properly and may, in fact, be necessary to provide adequate circulation in divided tanks if other arrangements fail.
To be honest, I am not a big fan of divided tanks. I have found through experience that my bettas seem to have a shorter life span when subjected to the stress of constantly having neighbors. But that's just me.
However, when I DID do divided tanks in the beginning each compartment had it's own filter with the one heater for the tank in the middle.
I am attaching a picture of the 20 gal. tank I used to have split 3 ways so you can see what I mean.