SLAM help please!!

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M

mbeck5

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May 16, 2014
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Dallas, Tx
Good morning all. The issue I have been dealing with is having to add 2-4 gallons(121 oz) of 8.25 bleach per day but passing the OFCLT until this past weekend when I did not pass so started the SLAM process. You can see the results below. My CYA was 40 when I started and this morning still appeared to be 40 so 16 is my shock number according to the chart, however it does not appear to be improving. This morning's loss was 3.4, yesterdays was 2.0. The FC numbers on the lines where bleach additions are made is a calculated number at +1.9 per gallon. This morning the CC was 0, TA -70, CH -300, PH - 7.9, CYA - 40.

Wondering if I am reading my CYA number low and perhaps should bump up the shock number but not sure. Any suggestions would be much appreciated. Also the water is clear and beautiful, no visible signs of algae.

Day Addition Time FC Overnight Loss

Sunday 6:30 pm 4
add 7 17.3
9:00 pm 19
add 0 19
Monday 6:30 am 15 -4
add 2 18.8
2:00 pm 12
add 3 17.7
6:30 pm 11
add 4 18.6
9:00 pm 18
add 0 18

Tuesday 6:00 am 16 -2
add 1 17.9
1:30 pm 12
add 3 17.7
5:30 pm 13
add 2 16.8
9:00 pm 15.5
add 1 17.4

Wednesday 6:30 am 14 -3.4
add 2 17.8
 
Last edited:
Good morning Mike. Adding 2-4 gallons per day would appear excessive. If I'm following your notes above correctly, it looks like you have been trying diligently to keep your FC at/above 16 because you failed an OCLT correct? During this SLAM, have you been doing all the other SLAM requirements such as pump on 24/7, brushing the pool, checking any small niches/lights for algae access, cleaning the filter? If there's ANY algae hiding in those places, it will be noted on your tests. Losing more than 1 ppm on your OLCT does confirm you have organics somewhere eating your good chlorine, so you need to keep the SLAM going. During the day however, FC will go fast simply from the sun, so it's a constant battle.

Next time when you post your test results, don't worry about PH since it's skewed during a SLAM, but continue to post for us the FC and CC. If you're sure the CYA is 40, no need to re-test each time either. It won't change that fast. Of course continue to post your OCLT each next morning. Let's see what other s have to say about your situation as well.
 
Thanks for the response and you are correct. I had been using 2 - 4 gallons a day and passing the OCLT until the past weekend when I began the SLAM process Sunday night. Been cleaning the filters and brushing the pool daily but I cant tell you that I am 100% certain about the CYA test results. Checking separately, my wife and I agreed on 40 so that is the level I used. CC has been zero, no signs of algae, water is beautiful. Cartridge filters look dusty but no discoloration that I can detect. In the past before TFP had black, green and yellow algae but all has been great since I converted last year. Will keep on it and let you know the results tomorrow morning. Thanks again.
 
Have you pulled out the light and the ladder?

I have been slamming as well and the sun has been eating the FC up at midday. My water looked pretty darn good (clear but not sparkling clear) when I started with maybe a .5 cc. No visible algae either until I pulled the ladder that I had scrubbed twice and found some in the crannies under the rungs. It took me about 7 days to pass the OCLT. My water looked so good the last few days that I would have stopped slamming too early if it weren't for that test.

Are you seeing any dead algae on the pool floor?
 
ouachita said:
Have you pulled out the light and the ladder?

I have been slamming as well and the sun has been eating the FC up at midday. My water looked pretty darn good (clear but not sparkling clear) when I started with maybe a .5 cc. No visible algae either until I pulled the ladder that I had scrubbed twice and found some in the crannies under the rungs. It took me about 7 days to pass the OCLT. My water looked so good the last few days that I would have stopped slamming too early if it weren't for that test.

Are you seeing any dead algae on the pool floor?
Click to expand...

No lights and I pulled the ladder last year so not an issue. Havent seen any algae anywhere(walls, bottom, filter cartridges etc) so a little confusing. Prior to TFP we fought all kinds of algae without success but for the past year no problem. If it wasnt for the FC loss daily and failing the OCLT, I wouldnt suspect a problem. Cleaned everything again this morning and bumped up the FC to 20 so will see if it helps. Overcast today so that should slow the daytime loss but we will see. Will post again in the am and thanks for responding.
 
Have you seen any increase in filter pressure since the start of the SLAM?

Keep up the SLAM and it wont hurt it to have the FC a little over the SLAM target. The FC SLAM target is the value you want to not drop below during the SLAM.

It most likely is a low level algae problem that hasn't been detected with the eye.
 
jaduck - 870 and 871 are 3 months old. More coming tomorrow just in case. Appreciate your asking. Just checked again and FC was down to 12 with no sun today and CC for the first time .5. Is it possible to have algae eat this much chlorine without being visible? Not many places for it to hide. Pool is a rectangle with no lights, just the inlets on one side and a bottom drain not being used. One skimmer attached to the first drain by the stairs, cleaned and checked okay.
 

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ping - have not noticed an increase in pressure past what I would expect from filters getting dirty. Both cartridges were well under maximum this morning when i cleaned them and they registered a little below the minimum at start up and this has been normal for the past couple of years. Todays numbers are below. Seems incredible that the numbers would drop so much. My wife did not check the level at 11 but did add one more gallon and when I got home at 4, the level was 12 with a .5 CC(first time).

Wednesday 6:30 am 14
add 2 17.8
8:00 am
add 2 21.6
11:00 am ?
add 1
4:00 pm 12
add 4 19.6
 
Good morning. The loss last night was 1.4 so FC this morning was 15 and CC was 0. Since the OCLT results have varied will keep at it today. Also should receive a new chemical shipment today just to be sure. Water still looking great, pump pressure still low.

Sunday 6:30 pm 4
add 7 17.3
9:00 pm 19
add 0 19
Monday 6:30 am 15 -4
add 2 18.8
2:00 pm 12
add 3 17.7
6:30 pm 11
add 4 18.6
9:00 pm 18
add 0 18

Tuesday 6:00 am 16 -2
add 1 17.9
1:30 pm 12
add 3 17.7
5:30 pm 13
add 2 16.8
9:00 pm 15.5
add 1 17.4

Wednesday 6:30 am 14 -3.4
add 2 17.8
8:00 am
add 2 21.6
11:00 am ?
add 1
4:00 pm 12
add 4 19.6
11:00 pm 14.5
add 1 16.4
6:45 am 15 -1.4
add 2 18.8
 
Yes, a pool can look clean and take a while to complete a SLAM. The OCLT results say to keep on SLAMing and you are getting closer to the end. You need to remember only two things consume chlorine, sunlight and organics. The OCLT removes sunlight from the equation so you are left with organics as the culprit.
 
Pool is a rectangle with no lights, just the inlets on one side and a bottom drain not being used.
Click to expand...

Why isn't it being used?? Non functional??? Or just prefer not to use it???
A possible source of your algae may be under the drain cap and/or in the piping. I know it may be a long shot, but there would be no circulation in the pipe if its not being used. No circulation would mean no chlorine is getting to it.
 
one_knight4u said:
Why isn't it being used?? Non functional??? Or just prefer not to use it???
A possible source of your algae may be under the drain cap and/or in the piping. I know it may be a long shot, but there would be no circulation in the pipe if its not being used. No circulation would mean no chlorine is getting to it.
Click to expand...

It is functional but we were advised by a pool repair company replacing our pump that the bottom drain was not necessary and detracted from the skimmers so we stopped using it about 2 years ago. Wouldnt hurt to run it for a while if that is a possibility.
 
A main drain isn't necessary, but if you have one it needs to be used so chlorine is circulated there. All pool plumbing needs to be used unless it is permanently taken out.


Sent from my iPhone using Tapatalk
 
n240sxguy said:
A main drain isn't necessary, but if you have one it needs to be used so chlorine is circulated there. All pool plumbing needs to be used unless it is permanently taken out.


Sent from my iPhone using Tapatalk
Click to expand...

Opened it up this morning. Hopefully it will help with this issue but wondering why I was told it was okay to leave it off? What you are saying makes sense.
 
I have no idea why anyone would say it's ok to leave it there without using it. It'll just sit there with stagnant water in it, and algae can start to grow there since chlorine can't get to it.


Sent from my iPhone using Tapatalk
 

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