Filter Blowing Sand Into Pool
I have an old Jacuzzi sand filter (17") and a brand new Hayward lx pro pump (1 1/2 hp) hooked up to my 24' round agp.
Got everything hooked up today, put 2 1/2 fifty lb bags of filter sand in, backwashed and rinsed the sand, and then set it to filter. Took a long time for it to prime and once it did it was blowing sand into the pool.
Also, it was surging. I set it to whirl pool (blower only) and no sand....sigh, thought I was all done... So it continues. This has not been a pleasant experience (recently installed the pool).
I have several comments to make based on the information you have provided. The sand blowing back into your pool could be caused by possibly to much sand, possibly a tear in one of the laterals, if the filter has them, or most likely a worn out spider gasket. If the filter has a multi port valve there is a gasket that is prone to wearing out and needing replaced. Once this is done the sand should stop blowing back into the pool.
One of my big concerns is matching a 1 1/2 HP pump with only 125 lbs of media. That much HP will be blowing a lot of dirt through the sand, it's not enough media for that size pump. A better match would be a 3/4 HP. My favorite would be a two speed pump where you could filter with 3/4 and do you cleaning chores with 1 1/2 HP.
My last consideration would be the number of returns you have. 1 1/2 HP performs much better with two returns. It needs the second port to return the water to the pool in an effective manor. With just one return the pressure backs up in the system causing other problems.
You also mentioned gurgling. The most common cause for this is an air leak somewhere in the system. Most air leaks will suck air with the system running and leak water when the pump is off. This might be an easy way to find it.