Is my lawn affecting my chemistry?

[MrcTag]

I've had an IG pool fro 3 years now and never had a problem holding free chlorine, this year has been very different. My water is clear and all of my other levels are fine but my TC and FC levels are zero. A pool store employee asked me if I had a lawn service and if I do he thinks some of the overspray could be locking up my chlorine. I started having my lawn serviced this spring (weed and feed spray) so I'm wondering could this be the reason my FC level is always at zero? If so why is my water still so clear? I also had my trees sprayed this spring.

TC 0
FC 0
PH 7.5
TA 100
CYA 60
TH 220

 

[JohnT]

If you are using a chlorine feeder, they tend to clog over time. How do you chlorinate? If you get a marginal algae problem started, the main symptom is high chlorine use. Shock the pool and it may fix your consumption.

 

[JasonLion]

Grass ferterlizer and related plant chemicals can use up a great deal of chlorine. They should only be using it once or twice a season, not reguarly and should be able to keep it out of the pool. Perhaps you haven't burned it all off yet, ie you need to use enough chlorine to catch up with any ferterlizer that got into the pool and once you have done that thing should be back to normal.

Another, less likely, possibility is that your chlorine test isn't working (perhaps the reagents are old?)

 

[MrcTag]

Grass ferterlizer and related plant chemicals can use up a great deal of chlorine. They should only be using it once or twice a season, not reguarly and should be able to keep it out of the pool. Perhaps you haven't burned it all off yet, ie you need to use enough chlorine to catch up with any ferterlizer that got into the pool and once you have done that thing should be back to normal.

Another, less likely, possibility is that your chlorine test isn't working (perhaps the reagents are old?)

The test kit is new and expires 2009. I've taken my water to 2 pool stores as well and got the same reading. I have shocked my pool with 8 lbs. of Burnout Extreme twice and have gotten a very high TC reading but my FC always reads 0. I do use a chlorininator which I keep full and the tabs are dissolving at the same rate they always did. I am running my filter 24 hrs a day as well so I know I'm getting the chlorine in the pool. Should I worry if the water is clear and the other chemicals are in a good range?

Thanks
Marco

 

[JasonLion]

It sounds like they got quite a bit of fertilizer in the pool and you haven't gotten enough chlorine in to burn it all off yet. Chlorine reacts very quickly with fertilizer to form combined chlorine compounds, which will have the effects you describe.

Without FC the water isn't being sanitized, so even if there isn't any algae it is still not safe. You need to keep adding chlorine until you can maintain a FC level and you don't have any more CC.

 

[Rob]

The worry with the water being clear and 0 chlorine would be the various nasty bugs we all carry being transferred in the pool.

With 0 chlorine, you run a risk of catching some pretty nasty stuff off your swimming mates, or even yourself, when you consider what parts of their bodies are submerged in the same water you have your face in

Algae or a cloudy pool doesn't even really bother me, its the other stuff that is the worry.

 

[Buggsw]

Jason, In this case, wouldn't it be good to have the phosphate level checked and possibly treated? From what I understand, fertilizers introduce a lot of phosphates - just saying, if that's what's going on, it may make sense.

 

[JasonLion]

Yes, the fertilizer will raise the phosphate level. Given how much chlorine it appears to be taking to clean it up, it may well have raised the phosphate level fairly dramatically.

However, the phosphate level is really not much of an issue. If the chlorine level is maintained at a safe level there won't be any algae and it won't matter that there is plenty of algae food (phosphate) in the water. The whole idea behind lowering phosphates is flawed. You lower phosphate levels so the algae won't have any food and the algae won't be able to grow in your pool when the chlorine level is too low. Fine, no algae. But when the chlorine level is too low the water isn't safe, algae or no algae. If you have enough chlorine to keep the water safe then you won't have any algae, phosphate or no. So why worry about phosphates?

I would rather have the algae there to give me a nice clear indication that I messed up the chlorine level, instead of having a nice clear pool (no phosphate thus no algae) that isn't safe because I messed up the chlorine level and viruses and bacteria, which I can't see, are everywhere.

Besides phosphate removers aren't exactly free and they then to cause the water to cloud up and clog filters or require extra vacuuming. Why go to all that trouble?

 

[MrcTag]

It sounds like they got quite a bit of fertilizer in the pool and you haven't gotten enough chlorine in to burn it all off yet. Chlorine reacts very quickly with fertilizer to form combined chlorine compounds, which will have the effects you describe.

Without FC the water isn't being sanitized, so even if there isn't any algae it is still not safe. You need to keep adding chlorine until you can maintain a FC level and you don't have any more CC.

OK I think I got it, thanks for all th replies and help. The pool guy did suggest to keep shocking until we can hold a free chlorine reading but I wanted to check with you guys first. He mentioned a "chlorine demand test" but I have no idea what that is or how to do it. It's supposed to tell you how much chlorine you will need to burn everything off I think.

I think I'll keep the lawn service out of my back yard from now on.