Help clearing my pool.

[Naculum]

All,

I have an 11,000 gallon salt water pool with a sand filter. I went away for a while and came back to a green pool. I shocked the pool with liquid chlorine (4 gallons of 8.5% liquid bleach). My plan was to floc after and to vacuum the waste, as I needed the pool cleared quickly (I know, floc is usually frowned upon). The floc did not work, and the pool is still cloudy, although there are tiny coagulated particles suspended in the water. So my plan now is to go with the SLAM method and see if this will clear the pool. I will need to bring my pH down to 7.4 (raised it to 7.8 for the flock). My CYA levels is also low (20ppm or so). My plan is to add liquid chlorine to keep the FC at 17 or so, checking every few hours and just keep adding chlorine. I have, finally, the TF100 kit that will help me measure both FC and CC during this process. My questions are as follows: (1) will the floc in the pool and the suspended particles mess up my sand filter, or will frequent backwashing prevent this and (2) should I add some DE to the filter to improve its efficiency, or would this be trouble, considering there is already floc and suspended particles in the pool. Any advice would be appreciated.

 

[Texas Splash]

Hello and welcome to TFP! About your questions ..

(1) will the floc in the pool and the suspended particles mess up my sand filter, or will frequent backwashing prevent this

If you didn't vacuum to waste, it could have very-well gummed-up your filter. Floc must be vacuumed to waste right away once it's settled.

(2) should I add some DE to the filter to improve its efficiency, or would this be trouble, considering there is already floc and suspended particles in the pool.

No DE. It's not going to help anything at this point.

Your first order of business is to SLAM (link below). Make sure to increase the CYA to at least 30 with stabilizer. An FC of 17 is too high right now, especially if you have a vinyl liner. So make sure to increase CYA to 30 then adjust the FC to the SLAM level of 12. If you find your CYA goes closer to 40, then your FC level would be 16. Later, if you find the efficiency of the sand was compromised by the floc, you can try a deep clean, but you may have to change the sand if it became too gunked-up by the floc. Hard to tell at this point.

Also, don't forget to update your signature with all of your pool info. It's the first thing we look at when reviewing a post. Hope that helps.

 

[tim5055]

Yup, Pat has it covered. It is not one of those situations where FC of 10 is good, so 17 must be better. You do not want to damage your pool.

 

[Naculum]

Thanks for the help. I wasn't able to vacuum to waste, because there was no precipitant to vacuum, so that's the crux of my question. Is this going to mess up my sand filter, since I was unable to remove the floc with debris?

I do have a vinyl liner, and a salt water chlorine generator. The Chlorine/CYA chart shows my shock level would be 24-31 FC, depending on my CYA level. Your recommendation is much lower than that. What should I shoot for?

Thanks again for your help.

I will change my signature once I figure out how.

Hello and welcome to TFP! About your questions ..
If you didn't vacuum to waste, it could have very-well gummed-up your filter. Floc must be vacuumed to waste right away once it's settled.
No DE. It's not going to help anything at this point.

Your first order of business is to SLAM (link below). Make sure to increase the CYA to at least 30 with stabilizer. An FC of 17 is too high right now, especially if you have a vinyl liner. So make sure to increase CYA to 30 then adjust the FC to the SLAM level of 12. If you find your CYA goes closer to 40, then your FC level would be 16. Later, if you find the efficiency of the sand was compromised by the floc, you can try a deep clean, but you may have to change the sand if it became too gunked-up by the floc. Hard to tell at this point.

Also, don't forget to update your signature with all of your pool info. It's the first thing we look at when reviewing a post. Hope that helps.

 

[mknauss]

The Chlorine/CYA chart shows my shock level would be 24-31 FC, depending on my CYA level. Your recommendation is much lower than that. What should I shoot for?

Your first post stated you had a CYA of 20, if that. So what is your CYA?

 

[Naculum]

Oh, I see now. That recommendation was base on the non-SWCG level. I have a SWCG so was thinking I would have to correct both the CYA and shock at the same time. But essentially I shouldn't shock to that 24-31 level because my CYA is so low. So essentially, I should bring the CYA to 30, and then shock to 12 PPM and continue that until the pool is clear. Then, considering I have a SWCG pool, should I eventually raise my CYA to 60-80?

 

[mknauss]

Yes. That is a great plan.