Wrong choice of battery in my view. Calcium/calcium batteries are not designed for deep cycling.
Something still wrong there though. I reckon you have other loads.
What is the fridge draw (Amps or watts) and how are the batteries being charged?
Cheers,
Peter

Magic eyes are not very magical - don't go by them. They are useless as a means of assessing the state of your battery.

Have the batteries tested. They could be buggered. 

The batteries you have sound as though they are really starting battery technology and not deep cycle technology. the difference is, the first type are designed to deliver a high current for a short period and recover the loss at a high charge rate over short period. They are not designed to give a long sustained low output or a slow recharge. deep cycle batteries are the opposite, they can give a short high discharge current but they can only maintain the voltage at a high discharge rate for a very short period where starting batteries can maintain the voltage for an extended period of a few mins cranking. deep cycle batteries can not accept a high rate of charge current compared to their actual capacity. A 100Ah deep cycle battery can't accept much more than 20 amps continuous until it reaches around the 70% state of charge, then that 20 amps must be gradually reduced to stop the voltage climbing to a point that will damage the battery cells. A start battery can accept over 100 amps if it had the same capacity as the deep cycle battery, all the way up to around 85% state of charge, then the charge rate must be reduced to avoid battery damage or all the electrolyte boiling away and that causing battery damage.
Combining calcium calcium battery with deep cycle batteries could be an interesting combination, the calcium calcium at the charge/discharge end and the deep cycle adding the capacity to recharge the calcium calcium quickly and accept the current from the calcium calcium batteries at a rate they can accept, the excess being stored in the calcium calcium batteries until the deep cycle can take in that current.
There is a better battery technology that actually out does both of these advantages, last longer and weigh a lot less, but many get upset when I point it out so I'll leave it at that

T1 Terry

Hi Paul,
Just some handy info for you BUT this refers to Deep Cycle Batteries - see www.energymatters.com.au/components/battery-voltage-discharge/

It would pay you to check with a battery dealer who handles the batteries that you have for the info on them. You can use Start batteries for running a fridge but don't expect a long life out of them unless you can keep them on "Float" - ie being fed by a power source.