Main drain or no main drain....that is the question

The main drain in our pool does seem to affect proper circulation and distribution of chems, especially in the deep end.

Years ago I decided to greatly reduce the flow through the main drain since its been said by experts here that main drains are unnecessary. The benefit of doing this was increased skimmer performance (yay!). That season I started noticing small spots of algae growing on a couple places on the deep end walls despite never letting FC drop below the recommended target level (boo!). Before reducing flow through the main drain there was never any algae.

The next season I went back to keeping the main drain wide open and haven’t seen algae since.

It seems greatly reducing flow through the main drain was creating dead spots in the deep end.

So at least for our pool, I’m glad there is a main drain.
 
  • Like
Reactions: SuzfromTexas
I often wonder about all the shaped pools. Mine is a boring l rectangle but very functional. 2 returns in the shallow end feed 2 skimmers in the deep end. No corners or turns to navigate like the freeforms. Some friends have the pool that I call the ‘3 circles’. I assume they have a lot more issues with dead spots.
 
A pool is to be brushed often and vacuumed when needed. A robot cleaner can provide most of the same effects. Swimming mixes the water.
 
A pool is to be brushed often and vacuumed when needed. A robot cleaner can provide most of the same effects. Swimming mixes the water.

Of course. In a perfect world we would all swim with many friends for hours a day. The reality of bad weather and having a busy schedule tho is that a lot of pools can sit unused for a week or 3. What about those times ? Or people with lazy Ls that don’t have returns in that area ? Wouldn’t extra growth be expected with lack of use in areas of poor circulation?
 
Chlorine disperses in water. I suppose 'dead spots' can occur, but I have never seen that in my pool.
 
Thread Status
Hello , This thread has been inactive for over 60 days. New postings here are unlikely to be seen or responded to by other members. For better visibility, consider Starting A New Thread.