I had this problem when I first opened my pool for the first full season. I have a Doughboy pool, and I very carefully opened the locking cover on the the strainer just in front of the pump. With the pump off, turn the cover slowly until there is air and/or water coming out. Do not take the cover off-the pressure from the pool will make it nearly impossible to get the cover back on before you have lost a lot of water. The air will be near the top of the canister and will bleed off. When water is flowing out, turn the cover back to the locked position. Turn on the pump. You may hear some air for a few seconds but it will work its way through the system. Once gone, you should be all set. A tiny leak between the pool and the pump can also give you this problem this can some times be found in worn valves or badly glued joints or cracks in the pipes. These leaks can be so small that the water coming out is negligible. One way to see if this is the problem is by restricting the flow into the system causing higher vacuum in the pipes if there are even more air bubbles getting into the system you will have to check the pool to suction side pipes for leaks.
When water is poured on the ground, air trapped in the soil may be released. As the water flows through the ground, it displaces air pockets, causing bubbles to rise to the surface. This effect is commonly seen in saturated or compacted soil.
Yes, bigger bubbles reach the ground sooner than smaller bubbles do.
Oil seepage..
Crude oil is the form of petroleum that bubbles up from the ground. It is a natural fossil fuel consisting of hydrocarbons found in certain rock formations.
Install a new filter
Sure
Water that bubbles up from the ground is typically referred to as a spring or natural spring. These sources of water usually come from underground aquifers and can vary in temperature and mineral content.
Probably not going to be adequate.
It should be on "FILTER"
Vacuum them into the filter.
gravel
garvel