Do not want a repeat of this season's opening

[tdp]

When we opened the pool this spring, we had ammonia. There were a lot of worms in the pool after a very rainy winter, and I guess their gut bacteria had eaten the stabilizer and made ammonia. Both CYA and FC were zero on opening; this had not happened the first season we opened. We had to use a huge amount of chlorine to neutralize the ammonia and it was awful. (It was definitely ammonia, because I used an ammonia drop test.)

What do I need to do this winter to prevent a recurrence? This might seem like a silly question, but how do you maintain chlorine with a safety cover on the pool (since you can't just easily lift a corner of the cover to add or test)? And if you do add chlorine, how does it get dispersed with the lines plugged & pump off?

I don't plan on closing until October.

Thanks!

 

[mknauss]

Pool School - Closing an In Ground Pool

Take a look at this. A pretty good review.

I do not close our pool so others will chime in if different.

 

[pooldv]

The main key is raising FC up to shock level and closing when the water is below 60°f. Ways to circulate chlorine are brush, broom, paddle, submersible pump.

 

[JoyfulNoise]

Did you open your pool early when the water temps were still below 60F?

Ammonia is not a certainty. It depends on certain types of bacteria and fungi growing in the water to consume the CYA and convert it to ammonia. So by closing the pool when the water is under 60F with shock levels of chlorine and algaecide (polyquat 60) as well as opening early gives you the maximal likelihood of not developing the microorganisms that generate ammonia.

You might also check your phosphate levels to see if your water has a large supply of algae nutrients available. When the FC goes to zero, water that is loaded with nitrates and phosphates is water that has the nutrients needed for algae growth. It's like a fish tank - if the nitrates, phosphates and organic carbon levels are high, algae will bloom and fish will die. In a pool with zero FC, warm water (above 60F) and lots of nutrients, you're asking for a green swamp with all the bad side effects. That's why opening below 60F is critical because algae/bacterial growth rates are restricted. Give them enough heat and food, and your in for a bloom.

 

[tdp]

Did you open your pool early when the water temps were still below 60F?

Ammonia is not a certainty. It depends on certain types of bacteria and fungi growing in the water to consume the CYA and convert it to ammonia. So by closing the pool when the water is under 60F with shock levels of chlorine and algaecide (polyquat 60) as well as opening early gives you the maximal likelihood of not developing the microorganisms that generate ammonia.

You might also check your phosphate levels to see if your water has a large supply of algae nutrients available. When the FC goes to zero, water that is loaded with nitrates and phosphates is water that has the nutrients needed for algae growth. It's like a fish tank - if the nitrates, phosphates and organic carbon levels are high, algae will bloom and fish will die. In a pool with zero FC, warm water (above 60F) and lots of nutrients, you're asking for a green swamp with all the bad side effects. That's why opening below 60F is critical because algae/bacterial growth rates are restricted. Give them enough heat and food, and your in for a bloom.

I definitely had ammonia; I bought a drop test meant for fish tanks and it showed an ammonia level that slowly dropped as I put in tons of chlorine.

I open/close my pool in Apr/Oct so water is quite cold. It was not a green swamp on opening at all; I just could not get a chlorine level to hold because ammonia sops it up like a sponge.

 

[JoyfulNoise]

I definitely had ammonia; I bought a drop test meant for fish tanks and it showed an ammonia level that slowly dropped as I put in tons of chlorine.

I open/close my pool in Apr/Oct so water is quite cold. It was not a green swamp on opening at all; I just could not get a chlorine level to hold because ammonia sops it up like a sponge.

Ok, that's good to know that you tested for it. I believe you that it's ammonia and unfortunately some people just get that problem. All you can do is close your pool and try to sanitize it as late as possible in the season.

If you are getting a lot of worms in your pool, that would suggest the cover is not keeping a lot of water runoff out of your pool. Rain water or snow melt is fine but water that hits surface soil and then runs into the pool would pick up a lot of soil bacteria along the way.

Does your cover keep the pool sealed against runoff?

 

[tdp]

I think it usually does, but we had several large rainstorms this past winter (that probably normally would have been snow), and that may have caused unusually high runoff. I have just put a line of lime around the edge of the pool deck; we'll see if that keeps the worms from crawling up onto the pool deck the next time it rains ?