Installing a main drain in an above ground pool is one of the best things you can do for it. It greatly increases water circulation which helps keep your pool clear, cleaner, and healthier. In-ground pools must have them by code, so that should tell you something.
A bottom center drain also makes it easier to keep the pool clean as the drain can suck up small debris and algae that settles on the pool’s bottom. Setting the pool return at the proper angle will create a whirlpool effect gathering most of the debris to the bottom center of the pool which is where the drain is. The drain then sucks up most of the smaller debris into the filter so you don’t have to vacuum as much.
What is a main drain exactly?
A main drain is a gathering pot with a grated cover over it that is dug in and placed flush and center with your above ground pool bottom before the liner is installed. Underground PVC piping is connected to this gathering pot which comes up out of the ground and connects to your pool’s pump on the front/suction side.
The main drain is then cut into the pool’s liner making a leak free seal using gaskets and a multi-screwed face plate. A valve at the pump is added to the pvc pipe to regulate the flow.
When the pool is full and the pump is turned on, the pump can now draw unfiltered water from the pool through that bottom drain instead of just the top skimmer. Drawing the water from the bottom of the pool to get filtered provides much, much better circulation as an above ground pool sends the filtered water back the to top of the pool.
Proper main drain installation comes with a valve so you can regulate the percentage of water coming from the main drain and skimmer and be able to turn either one completely off.
Pros and cons to having a main drain.
Don’t feel like reading a lot about it? Here are the pluses and minuses to getting a main drain.
Pros for the main drain:
- Greatly increases circulation
- Keeps the pool cleaner by sucking up bottom debris.
- Makes it easy to drain the pool down.
- Will slightly reduce chemical cost.
- Can greatly reduce the need to vacuum the pool bottom.
Cons for the main drain:
- Initial installation cost (I charge $500 complete)
- Makes one more opening in the pool liner which could leak. (not at all an issue if installed properly)