Yes I would get a bubbler along with a pump so you will not have to run your pump as often. I personally have two bubblers on my boat and it keep my fish happy and healthy ask anyone who tries to weight them in they are always lively.

Depending on how often you run your pump will depend on weather and number of fish. During the cooler months I only run my pump maybe a few times a day because I have the bubblers replenishing the oxygen in my well. During the hotter months I will run my pump at least every hour just to make sure my fish are happy.

As for a 7 AMP battery you will have to look at how many Amps your finder and pump will pull to see how long it will last. I have a 7 AMP battery and just to make sure I have no problems I will put it on the charger each night after a tourney.

Hope this helps,

FIT