Question about SLAMMING

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D

dmccarthy

0
Aug 8, 2015
65
Jeffeson, MA
High Phosphates

What should I do if my phosphate test came back over 2000ppm? I have all the other chemistry in-check as recommended by the pool school.

FC = 4-4.5 (mostly, does dip into high 2's on occasion)
CC = 0
PH = 7.5
TA = 100-110 (which when I do the CA conversion I think it puts it around 85-87 or so) I think that is ok
CH = 180-190
CYA = 50 (still a bit low, but I am slowly getting it to 70 as recommended for my SWCG)

The water looks clear. My pool company told me phosphates can eat up chlorine as well. Should I tackle the high phosphates and if so, what should I use? I have not officially done an OCLT. Should I do one first? Are high phosphates a pre-cursor to an algae bloom?

Thanks
 
High Phosphates

Do Nothing. As long as you maintain the correct FC/CYA ratio, your water will be fine. It would only be a concern if you had recurring algae blooms and if the recommended TFP FC/CYA ratio was not working.

FYI, phosphates are measured in part per billion (ppb) not parts per million (ppm).


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Do I shut my SWCG off during the SLAMMING process? Also, If I am understanding the SLAM process correctly...I continue to add chlorine until I read the correct levels ( In my case between 24-28 ppm of FC) and then keep testing until the CC are fall below .5ppm and the OCLT is less than 1ppm? The pump should be running the entire time, do I keep the SWCG off the entire time and do I leave the pool uncovered?

thanks,
 
dmccarthy said:
Do I shut my SWCG off during the SLAMMING process? Also, If I am understanding the SLAM process correctly...I continue to add chlorine until I read the correct levels ( In my case between 24-28 ppm of FC) and then keep testing until the CC are fall below .5ppm and the OCLT is less than 1ppm? The pump should be running the entire time, do I keep the SWCG off the entire time and do I leave the pool uncovered?

thanks,
Click to expand...

Very close, I would adjust one thing. Where you say "and then keep testing until the CC are fall below .5ppm and the OCLT is less than 1ppm?"

I would tweak that to say "and then keep testing and adding bleach often, once an hour would be best. Once the FC starts to hold between tests, then I can stretch the testing and adding to every few hours. Once the water is clear to the deep end, then I would look for passing the other criteria of <0.5 CC and <1 FC loss overnite."
 
Re: High Phosphates

How are you testing your water? To get a phosphates reading usually you have to be getting it done at a pool store. Often a pool store that *sells* phosphate remover products. Did I guess right?

You need your own test kit. The TF-100 or the Taylor's K-2006, both available from TFTestkits.net

Don't sweat the phosphates. They only ever come into play if you have algae and are having a *very* difficult time killing it all off. As long as your keeping enough chlorine in the water in relation to the CYA level you won't have that problem.
 
Re: High Phosphates

Thanks for the information. Sorry, meant ppb for phosphates. Did get it measured at a pool store. Was told that phosphates "eat up chlorine" and that I should lower them, but it sounds like based on the responses that is not necessary if the FC/CYA levels stay in check. My only concern is (and I have admittedly not done an OCLT) is that from at night when I test to first thing in the morning I get about a 1-1.5ppm loss in FC. It goes from about 4ppm to 2.7, but every day after running the SWCG for 10 hours it gets up to 4.5ppm or so. The CC seems to stay in the 0-.4 range. The water does look a little less clear as of late, however I have never not been able to see the 2 mains on the bottom of the deep end. Should I slam? Could I possibly have an algae issue?

Thanks again
 
Thanks for the replies. The water has been "pretty clear" all along, but I do get about 1-1.5ppm FC loss overnight. I do notice it is "duller" and less clear than I would like. I keep the FC levels at 4-4.5 and the CYA is at 70ppm. But usually first thing in the morning the FC is around 2.6 and then after running the pump for 10 hours during the day when I check the FC at night it is usually 4-4.5. CC are usually anywhere from 0-.4ppm.

If I started to SLAM this evening (if you think its needed) approximately how long before I could complete the test and start adding neutralizer? I recognize that each pool is completely different and it depends on when you are hitting your target #'s, but I have never done this before and just wanted to clarify (so to speak) as we have a family party in a few days and would hope to use the pool by then.

If I get the FC up to 28 tonight and then it holds overnight (with SWCG off, pump running and no additional chlorine added) and my CC gets eliminated can I start to reduce the chlorine first thing in the morning? Is there a minimum number of hours that the FC has to stay at that level for the SLAM to be effective at removing algae or is based purely on the FC numbers holding between tests and the CC? I do not think I have an algae issue, but my pool water does have high phosphates (2000ppb) and I was told that phosphates can "eat a lot of chlorine" too, but that they should not be an issue if the FC/CYA levels are kept in check.

Thanks again
 
Re: High Phosphates

dmccarthy said:
Thanks for the information. Sorry, meant ppb for phosphates. Did get it measured at a pool store. Was told that phosphates "eat up chlorine" and that I should lower them, but it sounds like based on the responses that is not necessary if the FC/CYA levels stay in check. My only concern is (and I have admittedly not done an OCLT) is that from at night when I test to first thing in the morning I get about a 1-1.5ppm loss in FC. It goes from about 4ppm to 2.7, but every day after running the SWCG for 10 hours it gets up to 4.5ppm or so. The CC seems to stay in the 0-.4 range. The water does look a little less clear as of late, however I have never not been able to see the 2 mains on the bottom of the deep end. Should I slam? Could I possibly have an algae issue?

Thanks again
Click to expand...
What you have described sounds like the very early stages of an algae bloom.

How are you testing to get that 1-1.5ppm loss overnight?

If your CYA is indeed 50ppm, you will need to maintain SLAM FC level at 20ppm. Standard OTO tests do not measure that high.

As mentioned, skip the phosphate remover and get a proper test kit. You will be glad you did.

Dom
 

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Overnight loss means algae or other organics that need to be eliminated.
There is no set amount of time for a SLAM. It is finished when the pool passes the 3 tests.
You hold the FC at the SLAM level until the pool passes.
No need for neutralizer, whatever that is.
Phosphates are irrelevant. Only matter if your are keeping the daily, non-SLAM, FC too low.

Looks like your pool might want the normal daily FC more near the higher level. Try for never less than 5ppm.
 
Phosphates do not eat chlorine. Algae eats phosphates and so high phosphate levels can lead to faster algae growth in a pool that does not have enough FC to kill algae faster than it can reproduce. The "Minimum FC" on the FC/CYA chart is the point where FC kills algae faster than it reproduces, so keeping it above that at all times makes phosphates meaningless. It does mean that if you drop below that level then a problem could creep up faster than a pool with lower levels, which appears to have happened when your FC dropped below 3. Dull looking water is one of the first visual clues of an algae problem, so you caught it very quickly.

SLAM is all about maintaining your shock level until everything is killed so you don't just get a relapse. That is why normal shocking doesn't usually last, a one time shot is not enough to kill a bloom. It takes time. Keep your FC around 28 until your water is clear and you pass the CC and OCLT requirements. You don't want to have to do it again.

As for chlorine neutralizer, don't bother. Even at full SLAM level the buffering effect of the CYA gives you an active chlorine level roughly equivalent to a pool with no CYA and 0.6 FC. That is less than most indoor public pools. Even if it is still up in the 20's when you have your party it is unlikely anybody would notice, you might even get compliments on how your salt pool is so much better than a chlorine pool ;)
 
Re: High Phosphates

I am using both a taylor K20005C DPD test kit and the Lamotte color Q7 liquid test kit and getting the same #'s for both so I think my numbers are pretty accurate. My CYA is actually at 70ppm right now. If I am indeed at the early stages of an algae bloom should I go ahead and SLAM? I think based on my CYA I need to get up to 28 correct? Would it be best to start the SLAM today or wait until tonight? How long do I need to maintain the FC at those levels in order for it to be effective at killing the potential Algae issue?

Thanks again
 
Great, thanks for the replies. Looks like I will start the SLAM today. Based on the pool math sheet I just plugged in my numbers for FC and CYA of 70 and for my size pool I need about 5 gallons of 12.5% shock to get it up to the 28ppm FC and then I would keep it at that level until it passes the 3 tests? Also, is there any need to lower the ph before starting the SLAM? I thought I read in one of the posts that someone recommended lowering the ph to 7.2 before starting the SLAM. Right now I am at 7.5 in a SWCG pool and since the ranges are 7.5-7.8 anyway is it ok that I leave the ph alone?

Thanks again for the helpful information
 
Re: High Phosphates

dmccarthy said:
I am using both a taylor K20005C DPD test kit and the Lamotte color Q7 liquid test kit and getting the same #'s for both so I think my numbers are pretty accurate. My CYA is actually at 70ppm right now. If I am indeed at the early stages of an algae bloom should I go ahead and SLAM? I think based on my CYA I need to get up to 28 correct? Would it be best to start the SLAM today or wait until tonight? How long do I need to maintain the FC at those levels in order for it to be effective at killing the potential Algae issue?

Thanks again
Click to expand...
If this were my pool, by your descriptions I would start the SLAM as soon as practical. You will need to test often (the more the better, but not less than 1 hour between) and maintain that shock level.

Neither of your FC tests will read FC above 10ppm. Yes, at 70ppm CYA you need to maintain 28ppm FC until you pass all three criteria for a SLAM:

1) The water is completely clear (no algae either).
2) you pass an OCLT
3) CC is less than 0.5ppm

Read here on how to SLAM
http://www.troublefreepool.com/content/125-slam-shock-level-and-maintain-shockingl

Dom
 
Re: High Phosphates

Dom is right on point. Get it early and it will go easier.

Bring it up to shock level and keep it there. The minimum for testing and adjusting the chlorine is twice a day, but five or six times is better.

Turn off your SWCG during the SLAM. It obviously can't be running when you are conducting the OCLT.
 
Yes, you want to lower your pH down to 7.2. This is because your pH will rise during your SLAM (liquid chlorine raises your pH, but then it drops as the chlorine is consumed so it ends up mostly the same after your SLAM) and the high FC can mess with your pH test so it is best to lower it first and then just leave it alone until your FC is back below 10.

Once you do that you will add enough chlorine to get up to 28 as you said. From there you want to test often, as much as every two hours if possible, and bring the FC back up to 28. Generally it is recommended to shut down your SWG during this to save cell life as you are already adding chlorine manually anyway. You will definitely want to have it shut down when you get to the OCLT.

Good luck, hopefully it will go quickly!
 
Re: High Phosphates

In addition to the above suggestion I would go ahead and look for hidden algae (under steps, in light niche, etc.) it loves to gather and multiply in such places where there is poor water circulation. I have no proof this is your issue, just a feeling it might be.
 

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