Low chlorine/No free chlorine

[ping]

There are two things I recommend you do when you receive your TF-100 kit.

1. Test the CYA with half of the sample water from the pool and the other half tap water. Mix this with the reagent and then the CYA level will be double the reading. This gives you a more accurate result when the CYA is above 100. With this information we can tell you how much water will need to be drained.

2. Raise the FC level to a minimum 10 ppm with liquid a couple of hours before it is dark. Take a FC reading when it is dark and take another one in the morning before the sun is up. This is the OCLT and it will confirm what most of us suspect is that you have organics in the water and you will need to SLAM the pool.

 

[mark46143]

OK, I have the test kit. The FC is 7, CC 2.5, TA 110, CYA as recommended above 50. I dont have the bleach or LC to get to 10 ppm.

This is reading. Will test FC tomorrow.

 

[Jeetyet]

Did you not do a PH test?

Not sure what you mean by "CYA as recommended above 50". If that statement means you diluted the sample with half tap water as suggested, did the test, and the result was "above 50", then THAT number must be doubled to get your real CYA reading, and thats the number needed to make recommendations for how to proceed. Your true CYA level is critical in determining what you should do going forward as to whether or not to do a partial drain & refill (and the volume required), as well as what FC level to maintain during a SLAM.

Now, if a SLAM is required, and I'm pretty sure it will be, and assuming your CYA is above 100, and since you have a SWG, the first thing you're going to have to do is drain & refill enough to get your CYA down around 70. (You also have the option of lowering it even further than that in order to do your SLAM and it won't require as much chlorine/bleach to complete the process. That would require a larger drain & refill plus you'll have to add CYA after you're done SLAMming.)

So, first step is getting an ACCURATE CYA measurement, adjust if needed. Second step is test PH level while FC is below 10, adjust if needed. Once you've gotten those two right, then, if required, stock up on bleach, and proceed with the SLAM process. Any other parameters can be addressed after you're done SLAMming.

Given your previous statements about the gunk in the lights I would pay special attention to those during the SLAM process. What I did was take them out of the niches and leave them hanging in the water, but bringing them up to brush thoroughly every now and then, as well as scrubbing in the niche itself, until SLAM was complete. And don't forget to check/scrub any other possible place algae could be hiding, especially under/around ladders if you have any.

I think I got all of that right, but if not someone more experienced will be along to make any corrections or additions. Good luck.

 

[ping]

You do have to go through the SLAM process, CC>.5.

You should lower the CYA level to 70 by replacing water.

Drop the pH to 7.2 before you start adding chlorine.

Run the pump 24/7 and brush the entire pool every day.

You will be finished with the SLAM when:
1. The water is clear.
2. CC<=.5
3. OCLT<=1.0

 

[mark46143]

Thanks for the info Ping/jeetyet. Yes the CYA was a 50/50 test so the actual CYA is 100.

Per ping, I did the OCLT and the results this AM were; FC 6. CC 1, PH is 7.5.

Any change on the above protocol?

Thanks

 

[jblizzle]

No. CC still too high. Replace water and SLAM.

 

[mark46143]

Thanks - any idea on how much to drop before refill? Thanks

 

[ping]

I'd shoot for a 30% replacement.

 

[mark46143]

Ok I have the pool drained below the skimmer and turned the skimmer off. The pool pump keeps kicking off. Any suggestions?

thanks

 

[jblizzle]

rent/buy a submersible pump.

Although your pump should be able to pull prime from the floor drain (assuming you are not getting air from the skimmer). Do you have the i1?

 

[mark46143]

I put the submersible in. I have the intelliflo VS so Im assuming it is thinking there's a blockage in the pool.

Wish they made a bypass to not kick off when pressure fluctuates!!! I have the skimmer blocked.

Thanks

 

[Patrick_B]

I put the submersible in. I have the intelliflo VS so Im assuming it is thinking there's a blockage in the pool.

Wish they made a bypass to not kick off when pressure fluctuates!!! I have the skimmer blocked.

Thanks

It is done for safety reasons. Unless I am misunderstanding this. Actually, I really wanted to ask why you can't just pull from the main drain(s)?

 

[Jeetyet]

Given your stated pool info, a drain of about 22" should get you in the ballpark. (About 400 gals per inch)

Since you have a vinyl liner make sure you never drain down to where there is less than a foot left in the shallow end.

 

[mark46143]

Thanks! I think I was right at abt 18-20. I'm filling now. We'll see.

 

[Jeetyet]

Good deal. Be aware that testing CYA via the dilution method will cost you some accuracy so your reading of 100 may be off a bit. Once you've refilled and the water has had time to mix well, test again without diluting. You may have to drain a bit more to get CYA where you want it.

 

[mark46143]

Ok, drained, refilled 24 hrs ago.

Test as of now:

Chlorine - 0
CC .50
Total Alk 190
CYA 90
PH 7.2

Is it appropriate to slam now?

Thanks

 

[Smykowski]

While it can be done, a CYA of 90 is at the very, very top end of the range of doable. It would be easier to do it with your CYA below 60, but it has been done before. You're going to be working with a very high FC level, and you'll have to be very diligent about keeping it up there.

 

[mark46143]

Thanks. So to be sure, I need to start at something north of 30 (FC) shock level and maintain at least 2x correct?

 

[Jeetyet]

Another 18" should get you down to around 70, mid-range recommended level for a SWG. Assuming your pool volume and current tested CYA levels are pretty close to accurate of course.

As previously stated, you can choose to drop CYA even lower to use less bleach/chlorine during a SLAM, but you'll have to add some CYA back afterwards to get back in the recommended 60 to 80 range for your SWG.

*edit*

Shock level for CYA of 90 is about 35. For complete details on proper SLAMming technique click the link in my signature

 

[mark46143]

Got it. Thanks. I reviewed the link and it had calcs for up to 80, just wanted to be sure. I drained some more water and am refilling currently.