Getting FC up and maintained

[KCPW]

Hi,
My pool has been clear however I haven’t been able to get a free chlorine reading to maintain itself. It is staying below 1. Last night I added 4 gallons of shock and I have finally gotten my combined to 0 and no free chlorine loss overnight. I came home from work today and it tested at .6 PH and Alk are in range. CYA is at 35. Any thoughts? Prior to this I added phosphate remover on the advice of the pool store which did nothing. Pool was installed last summer and is about 22k gallons. Thank you for any ideas.

 

[nobody291]

haven’t been able to get a free chlorine reading to maintain itself.

It seems likely that you have something growing in the pool that's consuming chlorine, even if the water is clear.

4 gallons of shock

Do you mean 4 gallons of 10% or 12.5% liquid chlorine? If so, with the CYA level you mention, the pool should still have some free chlorine tonight, which is more evidence you have something growing.

You likely need to SLAM, which will be a multi-day process. But, it would be helpful if you added details about the test kit you are using to measure FC and the other parameters to your signature.

phosphate remover on the advice of the pool store

Most people here ignore phosphates, but since you used the remover (which I have done in the past as well, and regretted it), make sure your filter doesn't need cleaning. I have a DE filter which I needed to clean after each phosphate "removal", because the pressure would rise. I'm not sure how that might be different with your cartridge filter.

Pool store advice is not sustainable, and their testing is unreliable. There's a bit of a learning curve with TFP methods, but when you get to the other side of the curve, it's simple, reliable, and the water looks amazing.

 

[KCPW]

It seems likely that you have something growing in the pool that's consuming chlorine, even if the water is clear.


Do you mean 4 gallons of 10% or 12.5% liquid chlorine? If so, with the CYA level you mention, the pool should still have some free chlorine tonight, which is more evidence you have something growing.

You likely need to SLAM, which will be a multi-day process. But, it would be helpful if you added details about the test kit you are using to measure FC and the other parameters to your signature.


Most people here ignore phosphates, but since you used the remover (which I have done in the past as well, and regretted it), make sure your filter doesn't need cleaning. I have a DE filter which I needed to clean after each phosphate "removal", because the pressure would rise. I'm not sure how that might be different with your cartridge filter.

Pool store advice is not sustainable, and their testing is unreliable. There's a bit of a learning curve with TFP methods, but when you get to the other side of the curve, it's simple, reliable, and the water looks amazing.

Thanks. I’m using 12.5%. Filter pressure is staying at 10. I use the Taylor k2006 kit. I’m hoping if I can keep the free chlorine level up high enough it will kill whatever’s in there since there is nothing visible.

 

[PoolStored]

Hi,
My pool has been clear however I haven’t been able to get a free chlorine reading to maintain itself. It is staying below 1. Last night I added 4 gallons of shock and I have finally gotten my combined to 0 and no free chlorine loss overnight. I came home from work today and it tested at .6 PH and Alk are in range. CYA is at 35. Any thoughts? Prior to this I added phosphate remover on the advice of the pool store which did nothing. Pool was installed last summer and is about 22k gallons. Thank you for any ideas.

First, Welcome to TFP!!

I'm assuming that .6 PH, you meant .6 FC. Is that what you meant? With an overnight loss of 0, if that is true, you used all the FC you put in. If so, you need to get enough FC into the pool to handle your daily demand.

At CYA of 35, your CYA is 40. We only measure at the lines. You should get enough FC into the pool to maintain FC for your CYA. Follow this...Link-->FC/CYA Levels

For CYA of 40, your target is 5-7, minimum of 3 FC. You never want to get close to 3. So if you start the day at 7, and you use 6, you will be back at 1 (below minimums).

Can you post a full set of results? I would also recommend you get back to 7 tonight with LC addition, pump and wait 30 minutes and re-do the OCLT. Both tests in the dark.

Overnight Chlorine Loss Test

If you fail OCLT, then it is time to SLAM Link-->SLAM Process