I’m am having trouble getting enough chlorine in my pool this year. I’m in Michigan and it has been an unusually hot summer. (That’s a good thing by the way!) All of my water chemistry is in balance except my chlorine. I can’t get enough in the water to hardly register on either a dip stick or a liquid test kit. I have an automatic chlorinator that holds 12, 3" tablets. The pump is running fine and the chlorine is moving into the pool at about the expected rate. The water is crystal clear and I’m having no alge problems. PH looks good, stabilizer is in range and alkalinity is right where it should be. But no chlorine. The water has hovered right around 90 degrees most of the summer. I’m assuming it is just burning the chlorine out almost as fast as I get it in. I do throw a couple extra tablets in the skimmer once in a while just to try to push the levels.
Should I just leave well enough alone or is this something I need to be concerned with? I had a chlorine lock issue a few years ago and it was a pain in the butt to deal with not to mention extremely expensive. I hate to have to go through that process again if it’s not necessary.
Hello Ras5114 - We recommend not letting the tablets get down to little pieces before you put new tablets in the chlorinator. When they get down to half the starting size, add more tablets.
What is the stabilizer level in parts per million?
Hi Ras5114, Please post your water test results as we will need these to determine what is going on. Also is there any visible signs of algae in the pool or other organic material like leaves? There are two things that consume chlorine… Uv rays from sunlight and organic material like algae or leaves. Your Stabilizer (cya) level is really important as it acts as sunscreen for chlorine, if your stabilizer is too low then the sunlight will quickly burn off your chlorine and if your stabilizer is too high then it will make your chlorine ineffective.Thank YouPatrick
Thanks guys. I’ll check the chemistry tonight and let you know the results. I normally try to keep the chlorinator pretty full. I don’t let it get down to less than half before I fill it up again. With the heat we’re having I fill it every couple of days. My pool is in an area with very few trees. Other than a few bugs it stays pretty clean.
I realize my TA is a little low. I added 5 pounds of increaser last night but didn’t have time to get a good reading after adding it. I may need a little more. But I doubt that’s affecting my chlorine levels.
The pH and alkalinty are low but it sounds like you adjusted the alkalinity. How often have you been shocking the pool with either liquid or granular shock? How much shock do you use? How many gallons is your pool? Does the free chlorine register after you shock the pool?
The pool is just over 23K gal. I haven’t shocked very much this year. We haven’t had much rain and the pool has been really clear. It also doesn’t get a ton of use. Just my wife and I and an occational visitor. I have shocked about 4 times this summer. I use two bags each time. The chlorine level spikes after shocking but falls right back off after about a day.
PH is almost always low. For some reason, in our area it is really hard to keep the PH up. I add a lot of PH increaser over the year. I can get it up but it normally falls of over a couple of weeks.
Most one pound bags cover 10,000 gallons of water. We would recommend adding three bags of shock (cal-hypo) or 2.5 gallons of liquid chlorine (sodium hypochlorite). This will be the appropriate amount of shock for your pool. At that point the tabs should maintain the free chlorine level.
If this doesn’t work, let us know and we can recommend another method. That method includes eliminating tablets and only using liquid chlorine.
I would agree with Rob I would shock and make sure your feeder is filled to the top with tablets and then test regularly for the next few days to see what happens with your Free Chlorine. Also are you seeing any visible signs of algae? Please post back your test results to this thread to keep us in the loop.
Very little algae. I see a bit of “dead” algae that gathers around the corners and the seams of my liner but nothing in the water causing hazing. I use about 4oz of algicide per week just as maintenance. That seems to be working really well.
OK, so I’ve used three bags of shock and put it in after sunset to give it a better chance to work. I left the pump running all night and checked the chlorine levels the next day. Nothing. The Free Chlorine is registering virtually 0.
I’ve adjusted the alkalinity to about 60ppm. I’ve added some PH increaser to get my PH up but that always seems to be pretty hard to do. For some reason, in my area, everyone complains about not being able to keep their PH up. It’s at about 7.0 right now.
Again, my pool has stayed the clearest it has ever been this season. I just can’t register and Free Chlorine. I’m getting ready to close for the season in the next couple of weeks. Do I really need to worry about this or should I just close and start the battle again next season?
By the way, I need to order a closing kit. Any recommendations?
Your combined chlorine of 1.2 ppm indicates that you do have live algae in your pool and this organic material is consuming your free chlorine. I would suggest putting in 6 bags of shock and then test again, you should at this point show a Free Chlorine reading and your Combined Chlorine should be below .5 I would suggest getting rid of the algae before closing as you will have a mess on your hands when you open in the spring. I would add the shock in the evening and test in the morning. Please let us know how this works. Just to wrap up we are looking for you to have a Free Chlorine reading in the morning and your Combined Chlorine to be below .5 ppm Ideally for closing you will be at 3 PPM Free Chlorine.
When reading your water chemistry levels, the one reading I did not see is the CYA or cyanuric acid level. What is the most recent test results for this level? I know we have been focusing a lot on the pH and Alkalinity levels, and for a vinyl liner pool, keeping the pH in a 7.4-7.6 range is recommended. Keeping the Alkalinity in a 80-100ppm range will help stabilize the pH levels. Keep in mind that the acidity level of the pool will fluctuate when shocking the pool. Here are a few suggestions:
If you see any algae bloom popping up in your pool, yellow mustard, black, or green algae, you will need to treat the pool and eliminate this bloom. You will need to superchlorinate your pool and add the correct algaecide to KILL the algae bloom. Having a previous algae bloom that was not killed properly could cause some of the issues you are having. What you would typically experience is low chlorine levels followed by hazy water and then a hint of the algae bloom. Shocking the pool gives the appearance of the bloom going away, but soon after the hazy water and bloom re-appear. Again, if this sounds like your issue, you will need to kill this algae bloom properly and then you will expect your chlorine levels to be maintain.
Low CYA (cyanuric acid or stabilizer) levels. This issue will allow the majority of your chlorine to dissipate quickly. This is caused by dilution of chemicals due to the constant addition of water/rain or from not using enough tablets to adequately chlorinate your pool. How many tablets are you using each week? During the summer for a 23,000 gallon pool, it is recommended to use 3-4 tablets per week.
Heavy bather loads can cause a higher demand for chlorine. We would recommend using a Non-Chlorine shock (Oxidizing Shock) to assist in eliminating organic waste and to assist in freeing up your available chlorine after swimmers have been in the pool.
I hope this helps. Knowing that you are closing the pool down soon may tempt you to not put as much effort into this. Just keep in mind that if you are able to solve this issue now, this may prevent a headache come next pool season. Good luck and let us know if we can help any further.
I’m not sure if you saw my last comment but you may want to take the approach I suggested below
Thanks
Patrick
Hi Ras5114,
Your combined chlorine of 1.2 ppm indicates that you do have live algae in your pool and this organic material is consuming your free chlorine. I would suggest putting in 6 bags of shock and then test again, you should at this point show a Free Chlorine reading and your Combined Chlorine should be below .5 I would suggest getting rid of the algae before closing as you will have a mess on your hands when you open in the spring. I would add the shock in the evening and test in the morning. Please let us know how this works. Just to wrap up we are looking for you to have a Free Chlorine reading in the morning and your Combined Chlorine to be below .5 ppm Ideally for closing you will be at 3 PPM Free Chlorine.
Driving rain all weekend so I didn’t get the shock in yet. Hopefully tonight.
I checked my CYA levels. About 80ppm.
Still having trouble getting my PH up. My test kit is showing yellow. No mater how much of the solution I use to check the demand, I can’t get it to turn pink at all. I’m going to try to add some more PH increaser and see if that helps. I"m using your Taylor K2005 kit. It is a year old but seems to work pretty well yet. Is it possible that my test chemicals are just old?