Hello, me again. After nearly one month of struggling, the pool is still far away from a good shape.

OK, please allow me to start from the very beginning.
So, I inherited the pool from previous owner without much information about everything, but I did saw they were doing a good job in keeping the pool very clear last fall when I decided to buy the house. The pool was then closed for the whole winter. I hired a person from the company built this pool to open it on May 22, by the way, he told me to operate the pool pump 24/7 from then on till whole summer. So, I did.
It took me about one week to rebalance the water (extremely high TA out range of the measurement). After everything seemed OK, I started double-10 FC test. Can't remember exactly how many bottles of liquid chlorination I have used, about 50? and finally I got the pool passed the test! During this time, I changed the filter with new sand because of two reasons. First, the pump was on all the time yet no improvement of the water clarity was seen. Second, the sands are everywhere on the bottom of the pool indicating large amount of sand loss. OK, the sand was changed and the filter was checked! Immediately after filter changing, the motor was dead. It could run one minute each time I turned on the switch and then died of overheat. I thought maybe it is an old motor reaching its lifespan, then I changed a brand new same model motor after a good time research. For all the time without a functional motor running, I dumped three bottles of liquid chlorination to the pool every night; however, with only a short time of clarity improvement, I sadly found that the color is turning from blue to green slowly. Even more sadly, after experienced every trouble of motor changing, I found the new motor still will only last one minute before died of overheat. The exact problem of the old motor!
Now, it's the puzzling part! I have checked the voltage in three spots, motor, switch, and the breaker panel, and they are all 122 V! I am really confused because the wire connections of both motors are setup for 230 V (L1 and L2). I don't think the voltage dropped recently in the breaker panel because for those equipments requiring 230V, they have apparent thicker wires and are still remaining at 230 V. I don't think the wire connection in motor was wrong either since the old motor has been working all the time until it was dead. To my understand, if the motor will be used for 115 V, the connection should be changed to A and B instead of L1/L2. Did I miss something? Is there any switch in the motor that can swing the voltage between 115 and 230? Moreover, I studied the A/B connection and did not find any screws allowing wire connection even if I want to try the low voltage connection.
Please help! Many many many thanks in advance!
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my signature is here
OK, please allow me to start from the very beginning.
So, I inherited the pool from previous owner without much information about everything, but I did saw they were doing a good job in keeping the pool very clear last fall when I decided to buy the house. The pool was then closed for the whole winter. I hired a person from the company built this pool to open it on May 22, by the way, he told me to operate the pool pump 24/7 from then on till whole summer. So, I did.
It took me about one week to rebalance the water (extremely high TA out range of the measurement). After everything seemed OK, I started double-10 FC test. Can't remember exactly how many bottles of liquid chlorination I have used, about 50? and finally I got the pool passed the test! During this time, I changed the filter with new sand because of two reasons. First, the pump was on all the time yet no improvement of the water clarity was seen. Second, the sands are everywhere on the bottom of the pool indicating large amount of sand loss. OK, the sand was changed and the filter was checked! Immediately after filter changing, the motor was dead. It could run one minute each time I turned on the switch and then died of overheat. I thought maybe it is an old motor reaching its lifespan, then I changed a brand new same model motor after a good time research. For all the time without a functional motor running, I dumped three bottles of liquid chlorination to the pool every night; however, with only a short time of clarity improvement, I sadly found that the color is turning from blue to green slowly. Even more sadly, after experienced every trouble of motor changing, I found the new motor still will only last one minute before died of overheat. The exact problem of the old motor!
Now, it's the puzzling part! I have checked the voltage in three spots, motor, switch, and the breaker panel, and they are all 122 V! I am really confused because the wire connections of both motors are setup for 230 V (L1 and L2). I don't think the voltage dropped recently in the breaker panel because for those equipments requiring 230V, they have apparent thicker wires and are still remaining at 230 V. I don't think the wire connection in motor was wrong either since the old motor has been working all the time until it was dead. To my understand, if the motor will be used for 115 V, the connection should be changed to A and B instead of L1/L2. Did I miss something? Is there any switch in the motor that can swing the voltage between 115 and 230? Moreover, I studied the A/B connection and did not find any screws allowing wire connection even if I want to try the low voltage connection.
Please help! Many many many thanks in advance!
- - - Updated - - -
my signature is here