Will low cc go away without SLAMing and a couple of other questions

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spylab

spylab

0
Jun 29, 2014
20
Fort Worth, Texas
My pool is about a month old now. I have the TF100 test kit and made a log for my water tests with info from this site on my goal levels.
I have my goals as FC 3-5, PH 7.5 to 7.8, TA 60-80, CH 50-300, CYA 70-80, Salt 3000PPM.
I was working on understanding CYA and SLAMing.
Yesterday my water tests showed FC 3.5, CC 0, PH 7.8, TA 120, CH 100, CYA 80, Salt 3200 ppm. My pool is normally very stable with just myself and my 6 yr old black lab using it. Yesterday my 2 yr old grandson and his parents came over and my grandson pooped while in the pool which has happens every time unfortunately. The last time I raised the FC it stayed around 10 for 3 days and I did not swim at all because I had seen in my SWG manual not to swim when the FC was above 3ppm. This was only his 3rd time swimming but I do not want to close my pool down for days every time he comes over.

I ran the chlorine test only this morning and got FC 2.5 and CC 0.5.

When considering if I should SLAM the pool I noticed the chart for target FC with SWG and my CYA of 80. It says FC 4 to 6 ppm and shock level 31....Should I be aiming for a FC of 4-6 ppm instead of the 3-5? With the CC at barely 0.5, will it go away with running my SWG longer?

So far I have only run the SWG for 4 hours a day. I leave the ozone on because I have a severe immune deficiency and just like that it can kill some things chlorine can't as effectively. I read all of the poop in the pool threads :) I did appreciate the comment from the nurse (my profession before becoming disabled) that we can over worry about catching stuff.

Please advise on my goal water levels and what changes I should make. Do you think I need to SLAM the pool at this point? If I do SLAM, it looks like my target FC is 31, how low does it have to be before I can swim again? Do you recommend dropping the PH for SLAMing. Also I read not to lower TA just to reach a number but mine is 120, does it need to be adjusted? Not sure if it can cause slight cloudiness to the water.

Thanks so much! I really love this site!!
 
LOTS going on there...

1) You're safe to swim up to shock levels. FC at 10 is no problem at CYA 80

2) At CYA 80 your minimum FC is 4. Stay above that to stay out of trouble. Disregard the SWG manual telling you that above 3ppm is unsafe.

3) 0.5 CC is no big deal. It should go away on it's own so long as you maintain your FC at adequate levels.

4) Consider bumping FC to 6 or so with bleach before family comes to swim if you're running close to the minimum.

5) Get the kid a stash of swim diapers...
 
Thank you so much! I have him in swim diapers!! I have suggested coming over right after dinner (like all 3 visits have been) may not be the best timing LOL. I am changing my FC goal to the 4-6 range and increasing SWG time to stay there. I don't know why but I really like pool chemistry and really appreciate the help!
 
Consider bumping your target FC to 5 or 6 anyway. There are good reasons for this. As you see, an incident causes FC to drop below target. And, you may be dropping below target during the time the pump and SWG are not running too.
 
Since you've been running on the low end of the TFP recommended FC levels, I would advise that perform an overnight chlorine loss test (OCLT). You should check to make sure your FC is holding overnight or else you could have something lurking in your pool.

Also, I know it's your grandchild and all but I would have a sit down with your son/daughter and inform them that the child needs to poop before going in the pool. Post-prandial intestinal activity plus rapid body temperature change in pool water is a perfect recipe for inducing defecation especially in a child with little or no bowel control. Considering you have an immune deficiency, it's not good to have poop in the pool.
 
Thanks so much everyone, I will aim for a FC level of 6. I am looking up how to do the OCLT.

I know his parents do not enjoy the aftermath any more than I do, we will definitely be discussing it again before his next swim day.

I threw in a little "shock" Dichlor that came with the pool that should have added about 5ppm to my chlorine level. I had added water to the pool yesterday also. This morning the FC was 4 and the solution had such a fine hint of pink I did not waste the drop to test for CC since it was barely 0.5 the day before. Only the dog swam today so I threw in some more Dichlor...this stuff came with the pool and I can't make myself waste it and figure I can't just throw it in the trash anyway so I am using it up. It is almost gone, looking forward to going with bleach!
 
Thank you for that comment, unfortunately I had already put the last bit in. At least I am done with it. I will check my CYA level again tomorrow and see where I am. I had forgotten about that, newbies like myself can have trouble remembering all of this stuff at once. It really helps to have someone discuss this stuff! I promise I have been reading and even took notes, it is the practical application that helps me remember.

I am having to add water 1 or 2 times a week. Our temps are around 100 F, with some wind and my very large labrador likes to swim, get out and take significant water with him to shake off before getting back in. I call him my water exchanger and he pesters me to open the pool everyday for him even if I don't swim. I did get my solar sails in place a couple of days ago to provide some shade to the pool and the water temp has dropped from almost 89 F to 85 F. Not sure if water temp has bearing on anything yet but with the other factors I am already adding fresh water to the pool so the CYA should go down.

At start up I put in the recommended amount of CYA instead of partial then testing (lesson learned) so it has been high from the beginning, it was around 100+. Am I better off aiming for the lower end of the range like 70 instead of 80?
 
If you have the drag-out / splash-out loss you describe, your CYA should come down soon enough. If you want it to come down faster, backwash your filter for a while and water your lawn and plants.

Temperature is mainly an issue for calcium scaling. If you have hard water (high CH), then you can use PoolMath to calculate your CSI to see if you're in danger of scaling. Just enter your water chemistry numbers, pool volume and temperature and the CSI will get calculated automatically.
 
What Sunny said.
spylab said:
I am having to add water 1 or 2 times a week. Our temps are around 100 f, with some wind and my very large labrador likes to swim, get out and take significant water with him to shake off before getting back in. I call him my water exchanger and he pesters me to open the pool everyday for him even if i don't swim. I did get my solar sails in place a couple of days ago to provide some shade to the pool and the water temp has dropped from almost 89 f to 85 f. Not sure if water temp has bearing on anything yet but with the other factors i am already adding fresh water to the pool so the cya should go down. CYA does not go down through evaporation, so would not change in relation to temperature. However, as Sunny has stated, temperature would affect your CSI.

At start up i put in the recommended amount of cya instead of partial then testing (lesson learned) so it has been high from the beginning, it was around 100+. Am i better off aiming for the lower end of the range like 70 instead of 80?
Click to expand...
With your climate and the water replacement described, I would advise aiming for CYA 80. Since you have enough water being physically removed that your CYA has dropped, you would need to keep bumping your CYA up if you aim for 70.

How to perform an OCLT

Also, based on the water replacement you have described, I would advise you to monitor your salt level.
 

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Abigail K said:
What Sunny said.

With your climate and the water replacement described, I would advise aiming for CYA 80. Since you have enough water being physically removed that your CYA has dropped, you would need to keep bumping your CYA up if you aim for 70.

How to perform an OCLT

Also, based on the water replacement you have described, I would advise you to monitor your salt level.
Click to expand...

One point to make that is not in that web link -

There has been some discussion of this but I believe the consensus opinion is that an OCLT should only be performed while at shock chlorine levels. Doing an OCLT at target FC levels is not advised.

Perhaps one of the more senior members can point us to a thread on that issue but that is what I remember. Again, it's not in the official documentation for performing an OCLT but I believe it is the recommended approach (OCLT only at shock FC levels)
 
I did one last night. My FC was 9.0 at 2100 and 9.0 at 0500, CC 0.5. My CYA is now about 75 (I had added water since the last test). My PH is 7.8.

I am curious to know if the test only works at shock level and if so does it have to be at the full level like 28-31 range for my pool. Seems chlorine would disappear at any level if it were attacking nasty stuff in the water. I really like the theory behind the test. I am looking forward to learning more.
 
There has been some discussion of this but I believe the consensus opinion is that an OCLT should only be performed while at shock chlorine levels. Doing an OCLT at target FC levels is not advised.
Click to expand...

I'm curious about this too. Is the worry that you might pass an OCLT but still have organics in the water at normal FC levels, or that you might fail it even if things are fine? I've done the OCLT casually many times at normal FC and passed.
 
Here is one thread on this topic-

http://www.troublefreepool.com/threads/79546-OCLT-test-question?highlight=OCLT+normal

Basically the OCLT was conceived as a test to be performed at SLAM FC levels. So at an FC of say 25 (just for kicks) then a 1ppm loss is not much.

However, if your target FC is 6 and you lose 0.8ppm, that's actually a decent percentage of your chlorine. So for an OCLT at target FC levels, you may truly want the loss to be 0 or no more than than 0.2.

However, one could argue that you are so close to the tolerance of the DPD-FAS test (0.2 ppm/drop) that trying to see a 0.2ppm difference doesn't make sense.

So a true OCLT is really only done at SLAM levels. Any other FC level for an OCLT is less than ideal and could give you a false sense of security.

[EDIT]

I think the theoretical basis for doing the OCLT at SLAM FC levels is this -

Chlorine lose rate (ppm/hr) is not a constant but rather proportional to chlorine concentration. So at higher concentrations, you'd expect to have a greater rate of chlorine loss than you would at lower concentrations for the same sample of water.

Therefore, if you pass an OCLT at higher concentrations, then any loss you do measure will be that much less at lower concentrations. But, if you detect a measurable loss of FC at target levels, then there's a good chance that loss rate will be much higher at shock levels and therefore lead to a greater overall loss.

[END-EDIT]
 
I added a gallon of bleach to my pool and my FC was at 17.5 when I tested the next day. Not enough to bring it to the desired shock level of 28 for a SWG pool with CYA of 70 but the CC that was holding at barely 0.5 did disappear.

Does the CC level of zero indicate nothing bad in the water (at first I assumed it does but thought I better ask)?
My goal is to find out how to make sure the water is perfectly clear of anything bad. I understand the OCLT at shock level will but was wondering if it is necessary since my CC is back to zero.

I really appreciate the explanation of the OCLT and it is now my go to process if there are anymore accidents in my pool!
 
You have nothing bad in your pool when you pass the three criteria for ending a SLAM - clear water, CC < 0.5ppm and OCLT < 1.0ppm

CC's are not a good indicator of a clean pool because they can fluctuate a lot. CC's can come from anything - live algae, dead algae, bather waste, bird pooping in your pool, leaf litter, etc, etc. Anything organic will be broken down by FC and turned in CC's.


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