Need help with my SLAM

[skinpath]

Hi all - I need some help with the SLAM process. I’ve been going through dozens of gallons of 10% chlorine to maintain the pool at SLAM levels over the past week and although there has been marked improvement in the appearance of the pool, the chlorine continues to be consumed at a very brisk rate and doesn’t show any sign of slowing down.

Some background - My wife and I recently moved to upstate New York and bought a house with a pool (pool details in signature). Neither of us have ever owned a pool before. Before we moved in I read extensively about pools on this site. Thank you for all of the wonderful information!

The pool we inherited didn’t seem to be in very good condition. Although it was only mildly greenish (and very cloudy), brushing the side kicked up abundant half-dead algae and debris and the cartridge filter was caked with the same stuff. Ran some preliminary tests (using the TF100 test kit), cleaned the filter, and starting following the SLAM procedure. Over the next couple of days the greenish color disappeared and then the pool slowly started to clear. For the past couple of days it has been almost entirely clear and looks ready to swim in.

The problem is that the FC is still dropping very quickly (both during the day and night) and I’m still using 8 to 10 gallons of 10% bleach every day just to keep it at SLAM chlorine levels. It’s losing 10-12 ppm just overnight (so it is nowhere near passing the OCLT) and this rate of chlorine consumption doesn’t seem to be tapering at all. I’m beginning to worry that I may be overlooking something or doing something wrong. It’s also getting expensive and time-consuming. I’m including below all of my test results (which are mainly FC) and my actions in response to results. I’m also including a few pictures of the pool. I put a dark hose into the deep end (8 feet at the deepest) for the pictures just to demonstrate how clear the pool is. I also have a heater, but I haven’t turned it on during the process.

DATE	TIME	pH	Chlorine (FAS)	Action
6/10	AM	6.8	1.5	ADDED 6 GALLONS 12.5%
6/11	AM		1	ADDED 6 GALLONS 12.5%
6/12	6:00 AM	7.2	13	ADDED 5 GALLONS 10%
6/12	10:40 AM		24
6/13	7:00 AM	7.2	5	ADDED 5 GALLONS 10%
6/13	2:00 PM		20
6/13	8:30 PM		12.5
6/14	5:30 AM	7.2	2	ADDED 5 GALLONS 10% AND 5 BAGS SOLID SHOCK
	10:30 AM		30
	4:30 PM		16.5	ADDED 6 GALLONS 10%
	6:45 PM		32
6/15	6:00 AM		16	ADDED 2 GALLONS 10%
	10:00 AM		21
	12:00 PM		19	ADDED 2 GALLONS 10%
	4:00 PM		21	ADDED 3 GALLONS 10%
	7:00 PM		28.5
6/16	5:00 AM		14	ADDED 2 GALLONS 10%
	11:00:00 AM		17	ADDED 2 GALLONS 10%
	2:00 PM		18	ADDED 2 GALLONS 10%
	4:00 PM		23.5	ADDED 3 GALLONS 10%
	7:50 PM		25
6/17	6:00 AM		15.5	ADDED 3 GALLONS 10%
	9:00 AM		21.5	ADDED 3 GALLONS 10%
	12:15 PM			ADDED 1 GALLON 10%
	1:00 PM		25.5
	3:50:00 PM		18.5	ADDED 4 GALLONS 10%
	8:00 PM		25	ADDED 4 GALLONS 10%
6/18	6:00 AM		25.5	ADDED 4 GALLONS 10%
	10:45 AM		30.5	ADDED 2 GALLONS 10%
	3:45 PM		23.5	ADDED 5 GALLONS 10%

	CYA	ACTION
6/10	<20	ADDED 120 OZ CYA
6/12	40-45
6/14	40-45
6/18	40-45

	TA	CH
6/10	75	325
6/11	70
6/12	310	375

Other notes - The pool has two skimmers, two main drains, and four returns. Three of the returns are in the shallow end, around the stairs. One return is at the deep end. They all have a forceful flow. I’ve been brushing the sides and floor as aggressively as I can and vacuumed a few times as well. I’ve used a small brush to try and get in the crevice behind the main drains and beneath the ladder. I’ve drained and cleaned out the filter itself with dilute bleach and replaced the filter cartridges. The skimmers seem to be working appropriately and I’ve been keeping them and the pump basket clear.

A note on my alkalinity level - The pH of the pool was initially low (less than 6.8) and I made the embarrassing mistake of trying to adjust it with baking soda instead of soda ash or borax (I ended up adding a lot of baking soda). I did manage to get it up to 7.2 but, of course, now the alkalinity is high. I’m trying to follow the process of lowering the alkalinity by raising the pH (using a primitive waterfall-type feature- you can see it in one of the pictures).

A note on CYA level - The TF100 kit includes a 50 ppm CYA standard, which is great practice for performing the test. Unfortunately, when I used to 50 ppm CYA standard, the black dot is not totally obscured when the test tube is filled to the 50 ppm mark. It’s mostly obscured, but not entirely. For me it becomes totally obscured around 35 ppm. My pool water is pretty similar - mostly obscured around 40-45 and totally obscured around 30-35. Not sure if this means that the standard is wrong, or I’m looking too closely. It would be nice to know although, either way, my CYA shouldn’t be more than 40-45.

Appreciate any help or suggestions you folks have.

 

[tucsontico]

Well I'm not an expert but I expect one of our gurus to chime in soon. Firstly, your signature block has not shown up on your post so we're missing important data (pool size, etc.). From what I can gather you are winning the battle against algae. Remember, it didn't grow overnight and it won't go away overnight. I know it seems that 8 days of a SLAM should be enough, but each pool is different. Don't give up yet!

However, you may have an issue with ammonia. If the pool sat with zero chlorine but with CYA in it a bacteria in the water can convert the CYA to ammonia. This will cause an EXTREME chlorine demand. I suggest you do a forum search for "ammonia." Hang in there!

 

[cowboycasey]

Welcome to TFP

You did study but you missed one important part you went nuke on it... while you would think that would work better it really just uses more chlorine... your free chlorine is holding so no ammonia

Here is the CYA chart Pool School - Chlorine / CYA Chart CYA is sunscreen for chlorine, if you take your free chlorine over the CYA level it no longer gets protected and burns off...

if your CYA is 30 your free chlorine would be 12
if 40, you FC is 16

What is happening is you're losing a bunch of your FC from the sun, you are still killing algae and whatever else is in there...

You are very close to passing believe it or not... that water is getting there

take your FC to 16, as many times as you can but don't go over, every 1 ppm over 16 the sun is killing the chlorine...

try checking and adding FC as below or as many of those times you can
6 am
8
10
2pm
5
7
9pm

See if your sig is here Trouble Free Pool

Let us know, I hope this helps

 

[skinpath]

Sorry about the signature - guess it didn't save the first time. I think I've got it now.

Thanks for the suggestion about the ammonia. I'll read up some more about it. Probably not an issue any more as my CC's have been 0.5-1 ppm over the past couple of days. But could have been slowing me down at the beginning. I'll grab an ammonia test from a pet store tomorrow and see if there is any left.

Thanks for the support cowboycasey, I hope I am getting close to being done! I'm overshooting some of my FC targets, because the FC levels are dropping so fast and I don't want them to dip below shock level. Two nights ago the levels dropped 10 ppm overnight. Last night the level was stable, but only because I added 4 gallons of chlorine (10%) after my last measurement. So again, the pool ate 4 gallons of 10% chlorine at night. So something must be chewing up the chlorine other than the sun.

 

[Mike1162]

Have you tested for CC?
Is the pool being used?

 

[skinpath]

Quick update - Yesterday I only had to add about 6 gallons of 10% to maintain SLAM levels and that is a noticeable reduction compared to all the previous days (and it was bright and sunny - pool is in the sun all day). I thought the pool was already pretty clear, but it has actually gotten a little clearer over the past couple days. If it gets any clearer I won't be able to tell that there is any water in there - . Current FC this morning was 25. I'm going to let the sun take it down a little for me (since it really is a bit high for my CYA) and then overnight I'll really be able to see where I stand.

- - - Updated - - -

Also - mike1162 - CC's have been consistently between 0 and 1 except for the first couple days of the SLAM. Nobody is using the pool now. I've been keeping them out because of the high chlorine levels.

 

[cowboycasey]

Keep up the good work, you are almost there.. Great Job

Its amazing how clear your water will be, just wait...

 

[tucsontico]

Another thought regarding the high chlorine use could be the age of the chlorine. Is the 10% bleach fresh? Liquid chlorine loses potency very quickly. FOR HIGH QUALITY CHLORINE (lower quality chlorine will degrade faster) 12.5% chlorinating liquid at even 90F will have a half-life of around 70 days. At 75F, the half-life is around 220 days. Remember that these are half-lifes so the time it takes to lose half its potency and the loss will be faster early on as the concentration is higher. At 90F, the drop from 12.5% to 10.0% occurs in about 22 days -- again, for high-quality chlorine.

May not be a factor but it is something to consider!

 

[skinpath]

Update - I'm using up about 4 gallons a day of 10% chlorine now. So things seem to be headed in the right direction, although rather slowly. My impression from reading some other threads is that when I am done slamming and pass the OCLT, I should probably be consuming less than a gallon a day (barring unusual circumstances like a pool party or heavy rainstorm). I do kind of wonder where the algae that is consuming all of this chlorine is coming from. Could it be in the piping?

tucsontico - thanks for the info on the chlorine half life. It's not staying with me long enough to really affect the strength (I'm running through it in less than a week) and it's really the ppm loss per day which is bothering me. But I'm buying the stuff from the local Wallmart. Any way to tell how fresh it is when I buy it (without taking a swig of it)? I have started storing it in the unfinished part of the basement for when my chlorine consumption gets low enough that it hangs around for more than a week.

 

[Mr Bruce]

If it's Great Value bleach, there is really good turnover on those so they are almost always new. If it's the 10% stuff, sometimes there can be some older stuff, the date code is YY ddd where ddd is the # of days we are into the year.

I'm pretty sure when you get done with your SLAM, you will be looking at a little less than a bottle/day.

 

[skinpath]

I’ve decided I have to give up with the SLAM procedure for now. I’m still losing losing 3-5 ppm FC overnight, but at this point I’ve been SLAMming the pool for nearly three weeks and I haven’t noticed any improvement in the past week. Water is clear and I have <0.5 CC every time I test. I don’t like the amount of chlorine I have to put in, but the real killer is that nobody is really able to use the pool while I’m SLAMming. At least at lower chlorine levels, someone will be able to use it.

 

[Mr Bruce]

... the real killer is that nobody is really able to use the pool while I’m SLAMming. At least at lower chlorine levels, someone will be able to use it.

Why do you think this? It is safe to swim up to SLAM levels.

It is of course your pool, but there is something in there consuming FC. If you don't kill it at, some point you really will have a pool people can't use.

 

[pabeader]

I did a search of the thread and I don't see where anybody mentioned the light. In one of the pics I see alight and I am wondering if you have removed it. Many times that turns out to be the source of an extended SLaM.

 

[skinpath]

Why do you think this? It is safe to swim up to SLAM levels.

It is of course your pool, but there is something in there consuming FC. If you don't kill it at, some point you really will have a pool people can't use.

I guess my understanding of the SLAM process was that you wanted to keep the level as close to the SLAM level without going under the SLAM level. I did read that it was safe to swim up to SLAM levels (but without going over). I figured that meant it was only really helpful when you just finished SLAMming and were waiting to drift down to normal levels.

Are you saying I can let people swim at a little higher than SLAM levels (since bathers will consume some of the chlorine), or that I can let people swim at up to SLAM level and then add more chlorine after they are done to get back up to SLAM levels? Either of those would certainly be helpful...

 

[tim5055]

I guess my understanding of the SLAM process was that you wanted to keep the level as close to the SLAM level without going under the SLAM level. I did read that it was safe to swim up to SLAM levels (but without going over). I figured that meant it was only really helpful when you just finished SLAMming and were waiting to drift down to normal levels.

Are you saying I can let people swim at a little higher than SLAM levels (since bathers will consume some of the chlorine), or that I can let people swim at up to SLAM level and then add more chlorine after they are done to get back up to SLAM levels? Either of those would certainly be helpful...

Yup, they can use the pool up to and even a little over SLAM levels. Is ti the best idea, no. As you point out the swimmers are just going to increase chlorine demand, chlorine you really want killing stuff in the water.

As an aside, as the chlorine levels go up it is really much harder on the swim suits than it is on the person/skin.

 

[skinpath]

I did a search of the thread and I don't see where anybody mentioned the light. In one of the pics I see alight and I am wondering if you have removed it. Many times that turns out to be the source of an extended SLaM.

OK - I feel like an idiot but, surprisingly, this is good. I was about to write a reply about how I don't have a pool light, just two main drains. I decided to do a quick search on pool lights and - lo and behold - it looks like I probably only have one main drain...and one pool light. The irony is that I've been reading about pool lights being the problem in a bunch of threads and been wishing I could have a pool light so that at least I would have a possible source for my chlorine loss.

Alright - I know what I'm going to do today.

 

[pooldv]

When is the last time you cleaned the filter? I would do that too if it has been a week or more. We swam daily while SLAMing last summer, CYA 70 and FC 28. Nobody even noticed except the guy with the TF-100.

It is safe to swim when
PH is 7.2 to 7.8
FC is above minimum and up to shock level for your CYA, [FC/CYA][/FC/CYA]
And the water is clear

 

[cowboycasey]

I had family come down last weekend, never been in my pool, they loved it and I asked them how much chlorine they "thought" was in the pool. less than 1 was the consensus because it did not smell like chlorine, they thought I was crazy when I told them it was at 32PPM. they could not even tell

 

[skinpath]

I took out the pool light today and there was a bunch of crud behind it, including algae-looking stuff. I got into the pool to scrub out the edge of the light box. The inside of the light box was surprisingly clean (I assume because it doesn't have access to light - sunlight, that is), so all the crud must have been right at the junction of the light and the pool. I scrubbed all the surfaces well and put it back in. Hard to believe such a small focus would account for all of the FC loss overnight, but I'll keep my fingers crossed. Thanks for bringing up the light again pabeeder.

Also, thanks to everyone for clearing up the swimming during SLAM thing. I'll definitely toss my kids in this weekend (with some goggles) and maintain SLAM levels.

 

[skinpath]

Sorry about the long hiatus, but had to start work and didn’t really have a lot of time to post and take care of the pool at the same time.

I’m sure everyone is on the edge of their seat to learn how things went…

Well, everything went great at the end! A few days after cleaning out the light the pool started to hold FC and it has been good since. We’ve been using it a lot and have had no problems either with the FC at shock levels or down to maintenance levels.

In fact, we were guests at a local country club and the kids were commenting on how the pool there smelled “funny”. What they were smelling was combined chlorine from a pool that wasn’t trouble free!

So, another win for Trouble Free Pool!