Consistently opening a cloudy green pool

[tzcq8l]

Hello TFP. I love your site and get great information from reading old posts, threads and consider TFP extremely helpful as a new pool owner. My problem is that I'm consistently opening my in ground pool to algae, cloudy green water color and 0 FC even though I close it with sparkly clear PH balanced water with a FC > 6.0 and CC < 0.5. I have a safety cover in excellent condition that's used during the winter months while closed for the past two years. I switched from a cheaper cover that used the water bags to hold it down. This is the only change I've made over the last 5 years regarding the pool opening/closing process. The openings take about a week of slamming and +$150 of shock or chlorine to get the water clear.
My question - Is this normal of other northern in ground pool owners opening to this algae, cloudy green water quality? I've been an in ground pool owner for about 5 years but memories from the 1970's of my parents above ground pool (Hendon 40x16x8 rectangle) opening were much better water quality. I feel like the water is getting contaminated somehow over the winter and every worm in the area crawls into the pool which I vacuum out during slamming. I've also measured ammonia in the water 2 years ago and slamming took much longer. One other suspicion I have is that the concrete isn’t pitched correctly around some areas of the pool and any water that enters the expansion cracks will drain into the pool. So, fall and spring rains plus melting snow water will partially get drained into the pool. Please let me know if you need more data about my question and thanks for any help.

 

[zea3]

Hi, welcome to TFP! Unfortunately we can't guarantee a method that will prevent a pool from going green over the winter, but there are some things you can do that will increase the odds of opening to a clearer pool. First is not to close too early. The water temperature needs to be consistently below 60 degrees to greatly slow down algae growth. We advise folks to bring the FC to slam level for their pool at closing, so that should be at least 10ppm, depending on the CYA level. You may want to run an overnight chlorine loss test to make sure there is nothing lurking in the pool before closing. If you fail the test you will need to complete SLAM process before you close the pool.

Also make sure you open after the last reasonable threat of a hard freeze has passed, but before the water temperature reaches 70 degrees. Again, you will need to get some chlorine in there to prevent any algae growth at opening. If there is anything you can do that will prevent runoff from going into the pool that will help keep the water clear.

You may want to peal back the cover every once in a while to check on the water quality. If it is starting to look bad but it is too soon to open the pool full, peal back the cover, add a gallon of bleach and brush the pool to mix it in and then put the cover back in place.

 

[tzcq8l]

Hello and thank you for your recomendations. I will implement them during this closing and winter season.

 

[samt]

This is what I do and I live in NY. About 2 weeks after Labor Day I put the cover on due to the leaves getting ready to fall and we're done swimming anyway. I leave the pump on and run it about 2 hrs a day and keep chlorine in it and maintain my needed level. When the water temp drops below 55 degrees , I shock it to pool schools recommend level. Blow the lines and pull the pump. In the spring when the water is about 50 or so, I hook up the pump, circulate and test the FC. I usually have a reading from the chlorine I put in last fall but very low. I run a full set of numbers and adjust slowly with the cover still on. Once the leaves have returned and all the junk from the trees quits falling ( Late May or this early June ) I pull the cover and vacuum and clean the bottom and sides.

 

[tzcq8l]

Thank you samt. I will be using some of your recommendations this fall, especially setting the FC to shock level at closing and covering/closing the lower water temp. I will be very happy if I can get a FC reading this spring. I know I'm getting a lot of unwanted water run off from the concrete. I've been pulling the pump and filter at closing. I may have to rethink that.