Skimmer Vs. Drain. If the pool receives a lot of leaves and other debris, more suction may be required at the skimmer than the main drain to adequately strain debris floating on the surface. Conversely, if dirt on the bottom of the pool is the principal contaminant, more suction is required at the main drain.
For me personally, I have found running around 60%-75% suction from the main drains and 25%-40% from the skimmers is adequate for proper skimming and adequate filtration.
Main drains are not required in an inground swimming pool, however, they are strongly recommended and can be extremely useful in some circumstances. The advantages of main drains are to give you the ability to drain the water from your pool without the use of a sump pump. This is useful when replacing your pool liner.
A swimming pool main drain uses suction to pull pool water through it. Heavy particulate matter that sinks to a pool's bottom is often sucked away through a main drain.
For the cleaner to operate at maximum efficiency, only the skimmer and cleaner valves should be open. So it is either main drain+skimmer or cleaner+skimmer. Never main drain+skimmer+cleaner all open at the same time.
When your pool skimmer has no suction, the cause is most likely a blockage. This can put the entire filtration system of the pool into question, as there will be low water pressure.
When constructing a new swimming pool, if you are going to use a main drain it is required that you use two. This is due to safety regulations to help prevent Main Trap Entrapment. Main drain entrapment occurs when the suction is so great through a single main drain that a person can become stuck on or in the drain.
How many skimmers do I need? The Association of Pool and Spa Professionals (APSP) advises that there should be a minimum of one skimmer per 400 sq. ft. of pool surface area.
Most of the dirt and debris that sinks exits the pool through these drains. To keep people from getting their hair or limbs caught in the plumbing, the drains are almost always covered with grates or antivortex covers (a cover that diverts the flow of water to prevent a dangerous vortex from forming).
Many pools do not have them. They are not required. They might add slightly improved circulation and can be helpful for removing debris, but there are ways to counter these without the floor drain.
The main drain for a pool is a suction port that should be located at the deepest point on the pool floor. A main drain is responsible for aiding in the circulation and filtration of the pool water. Having a properly working and dedicated main drain line can also allow you to fully drain your pool if necessary.
you can tell if your main drain is working by perhaps putting a leaf on it. If it sticks, its working. In any case though, the main drain is not why your pool is having a problem. It has nothing to do with your pool turning green.
MAIN DRAIN INSTALLATION:
The two main drains should be at least 3 ft apart from each other at the bottom center of your deep end hopper pad.
A skimmer is a necessary element of keeping a pool clean. The skimmer sits at the waterline and catches leaves, bugs and trash so they do not clog the filter. Skimmers with a second hole help keep the pump from running dry if the water level is unstable.
Pool suction drain injury, also known as suction entrapment, occurs when the drain of a wading pool, swimming pool, or hot tub suck in a swimmer's jewelry, torso, limbs, hair or buttocks. Evisceration, also known as disembowelment, could happen in case of buttock entrapment.
To turn on your skimmer valves, slowly make the handle go in line with the pipe. Now, this is the correct position for both skimmer(s) and floor drains to be bringing water to the filter pump.
When the pool pump is running, the skimmer works by pulling water and floating debris from the pool surface through a pivoting flap called a weir. After the debris passes through the weir, it gets collected by the skimmer basket. This continues until the pool pump is turned off.
If a skimmer is working correctly you should not see a swirling toilet-bowl like view. In theory, your pump should not be able to pull more water out of your skimmer than is coming in, unless the water level is really low or your Weir door is stuck in the up position.