First time having difficulty in 30 years

[myleso]

This was our 30th opening. Never had a problem before this year. Opened to a green mess. Went to pool place had the water tested with the following result:

FC: .77
TC: .81
CC: .04
PH: 6.6
CYa: 75

We purchased algaecide, several bags of pools shock Applied and in 2 days the pool was looking good. Only thing wrong is that we can't keep the clorine level up. We decided lower the CYa and do a SLAM. We pumped out water which we calculated to 10% which would reduce the the CYa to a more manageable 65. We got the pool test and now the CYa is 80! What can cause that. They said the phosphate was 200 which should be <125ppb. Haven't seen anything on TFP that mentions phosphates. So we still can't maintain the clorine level and don't want to do another pump out! Any suggestions appreciated.

Pool: 16 X 32 vinyl, 3ft shallow end to 8 ft deep end. I'm in MD.

 

[jmhjgh]

As many have posted before me, you can't trust the pool store CYA measurement. If the chlorine is not holding, then you have algae to deal with and you are likely not able to kill it with the chlorine levels you have been using because of the CYA.
I would get a decent test kit and measure CYA or see if someone on this forum is close so you can get a good measurement. You likely will need to exchange more water to get the CYA to a manageable level. If you have not done so, please read Pool School.

 

[bigglesworth]

I second everything jmhjgh said...

 

[YippeeSkippy]

We purchased algaecide, several bags of pools shock Applied and in 2 days the pool was looking good. Only thing wrong is that we can't keep the clorine level up. We decided lower the CYa and do a SLAM. We pumped out water which we calculated to 10% which would reduce the the CYa to a more manageable 65. We got the pool test and now the CYa is 80! What can cause that. They said the phosphate was 200 which should be <125ppb. Haven't seen anything on TFP that mentions phosphates. So we still can't maintain the clorine level and don't want to do another pump out! Any suggestions appreciated.

Pool: 16 X 32 vinyl, 3ft shallow end to 8 ft deep end. I'm in MD.

How are you chlorinating your pool? Are you using pucks? They add CYA with each puck so it is a vicious circle. If your CYA is out the roof high (which a pool store can't test for and it seems your store just makes up a number anyway) the only workable solution is water replacement. Get the TF-100 test kit and test that CYA yourself (might require dilution testing first) and report back to us and we'll help and advise you.

Ignore phosphates- as long as you start to keep enough chlorine in the water, phosphates and the expensive removers stores try to sell you are not a problem.

 

[Texas Splash]

myleso, you may be a junior member with only one post, but I respect someone who has had a pool for 30 years. No doubt you have a few stories to tell. But now we ask you to consider trusting the TFP method. See all the links from the TFP home page, or click on them from my signature below. First & foremost - order the TF-100 w/ speed stir. Don't buy another product from the pool store, nor should you have them test your water at this point. Without your OWN TF-100 test results, everything is a guess, but the symptoms you describe lean towards low FC, and it's battling your high CYA. Read the SLAM procedures as I anticipate you will need to do it. Also refer to the Chlorine/CYA chart link. This will all make sense when your kit arrives.

 

[Skitch]

So the times you did a "pump out" weren't difficult?!?

Use the force, Luke, use the force. Bleach, baking soda, borax, cyanuric and muriatic acid are all that a pool needs.

 

[woodyp]

Phosphates are NOT your issue. An adequate level of chlorine to kill your "bug" is. Do NOT let them talk you into any phosphate removers. Follow our SLAM methodology in Pool School and take control of it with one of our recommended test kits. We don't recommend the use of algaecides either btw.

 

[zea3]

If you used a dichlor shock then you added more CYA to the water. It takes about a week to register on a test once it is added. The CYA test is very subjective and is easily influenced by changes in lighting. Optimal testing conditions are outside in full sun with the sun at your back, holding the viewing tube at waist level. So the result from your pool store test was likely incorrect in the first place. I am also concerned with your low pH. It is possible that pH is lower than the test result indicated. It is important that you raise the pH to 7.0-7.5 to prevent damage to your pool.

We recommend pool owners conduct their own water tests using a high quality FAS/DPD kit such as a Taylor K2006 or a TF 100 . When you do your own tests you can control the test conditions so there are more consistent, reliable results.

Use PoolMath to determine what needs to be done to balance the pool.

 

[myleso]

Well after following the instructions for SLAM looks like we're out of the woods. We didn't follow it exactly for example we could'nt get the ppm up to the level in the chart. Anyhow the chlorine is now holding steady for a week now. Thanks to everyone who helped.


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