Grand SLAM

[Old Guard]

Over the past few months, I have become the "chemical czar" over 800,000 gallons spread out over four pools in three locations. This has been a 100% learning by doing, TFP and YouTube exercise. In the land of the blind, the one-eyed man is King.

One of my outdoor pools is a 126,000-gallon pool at my Reservoir location. I pulled lifeguard duty there last year and the pool was always just shy of so cloudy it was unsafe. I had no chemical responsibilities or knowledge then. This pool was kind of just turned out to pasture last fall. We shocked it with six gallons of 12½% bleach in February and again in Mid-May. Both times it cleared right up. We have been maintaining FC at 2-4 PPM since that second shock, but the water has turned cloudy again. I tried 3 quarts of Leslie's Ultra Bright Advanced Pool Clarifier yesterday. That made no difference at all. The attached pictures are from this afternoon.

So back to TFP and a SLAM education. This seems like a great idea, but this is a quasi-public YMCA pool that is used by roughly 100 bathers a day every day from late May to late September. Unfortunately, I just got the CYA up from 5 to 50. If I understand the SLAM idea, I need to dump 18 gallons of my 12½% into the pool to get it up to 20PPM. I need to hold it there until the pool is clear (probably next day) and free chlorine drop is <= 1PPM (no experience with that outdoors). Then I need to let the pool get swimmable again (<8 PPM?). That could take a week or more and cause a riot.

The one-eyed king would love some practical advice here. In case it makes any difference, I'm in central Mississippi. This pool is a stone's throw from the Ross Barnett Reservoir. The water is already above 81°F. CH is low. Everything else is within acceptable ranges. I have not yet added Boric Acid to this pool.

 

[kimkats]

I am sorry to say with that being a public pool you are going to have to see what the regulations are in your area for public pools. Most of the time they are no where near what TFP teaches for private pools. Now if you find you don't have to follow any real rules we can chat then.

 

[Old Guard]

It would appear to me that the state of Mississippi only publishes some pretty common-sense guidelines and no regulations. Since my original post, someone decided to put 276 ounces of Clorox Pool Crazy Clarifier in the pool (recommended initial dose 75 ounces). Now it looks like the Jolly Green Giant threw up all over the pool but the water in between the goop floating on the surface and the glop on the bottom is considerably clearer. My guess is that this is a case of treating the symptom instead of the disease.

If I do go ahead and SLAM this pool, is it OK to use Sodium Thiosulfate to knock the FC levels back down to swimmable or is the slow return to these levels part of the cure?

 

[kimkats]

The FC has to stay up for a while to get ALL of the algae dead and cleared from the pool.

How are you going to get the glop up and out of the pool?

 

[Old Guard]

They vacuumed it out with the effluent going overboard rather than being filtered and returned to the pool. It looked a lot better tonight but still a little cloudy and a little green. I switched my 15 GPD pump into full on mode at 7:30 this evening. The pool will have an extra 7½ gallons in it by sunrise. I also have six, one-gallon jugs loaded up and ready to go. Pool tested 5PPM free and total chlorine this morning. The pool will be closed tomorrow (Friday) but open again on Saturday morning. I don't think I can put the six jugs in if I cannot locate some local sodium thiosulfate. So far, no joy on that front.

 

[Mdragger88]

How are u testing this pool?
Your kit isn’t listed in your signature.
The SLAM Process requires you to MAINTAIN shock level for your cya FC/CYA Levels until u pass ALL 3 end of slam criteria:
~Crystal clear water
~Passing Overnight Chlorine Loss Test
~& cc’s of .5 or less
This is only achievable with an fas/dpd test as well as testing & replenishing fc multiple times per day. Every hour if u can.
It is not a one time addition of chlorine.
The more often u test & dose the faster the pool will clear & pass all 3 criteria.

As u have witnessed- clarifier really only makes matters worse when u have algae. Now u have algae & gunk.
It would likely behoove u to do a partial drain to get rid of some of the gunk & get cya down to 30 so it won’t require so much chlorine to reach slam level. This will benefit you in the long run as well since Having to regularly shock a public pool is often necessary for a variety of reasons.

My mother lives in a resort community that has 3 pools & we were talking about the way they are maintained & possible regulations. Looking this up on the MS health dept. website has confirmed what I suspected as far as a lack of regulation.

 

[Old Guard]

We have been using a K2006 three times a day for FC TC CC and pH. Once a week for TA and CH. I have recently changed that to only doing the 3X daily checks. One a month, we will have the water tested professionally for all of the other normal parameters. I am aware that, for the SLAM procedure, I will need to do FAS-DPD tests. For that, I plan to add R-0870 and R-0871, a magnetic stirrer and a 25 ml beaker to my bag of tricks.

Each of my pools have a pair of Stenner Econ-T peristaltic pumps. One is attached to a 55 gallon barrel of 12½% Sodium Hypochlorite. The other is attached to a 55 gallon barrel of Muriatic Acid. The pumps can be programmed to turn themselves on and off up to 24 times a day. The two chlorine pumps on my outdoor pools are capable of a maximum output of 15 GPD. The other six max out at 5 GPD. I can also pump chlorine out of the barrels into other containers should the maximum pump output not be sufficient to get to 20 PPM. In the case of my reservoir pool, I need 15 more gallons to get it there. My Clinton pool would require an entire barrel. I'm a little in the dark about what it is going to take to keep it there. If it takes 2 gallons per day to keep it at 5 PPM will it take the same 2 GPD to keep it at 20?. At 0 GPD, how long will it take to get back down to 5 PPM?

As a practical matter, if I cannot use chemicals to bring the slam down fast, I am out of luck this Summer as management tells me I cannot close the outdoor pools for days. Rest assured that I will slam them hard as soon as they close in the fall and then maintain them as if they were being used next winter. Maybe slam them again in early spring just for good measure. I will also go ahead and accumulate the things I need to manage the SLAM in case some other disaster (other than equipment failure) affords me the opportunity to do it. Maybe a liquid FMR will provide the excuse but those are amazingly rare.

Right now, I am putting both chemicals into all four pools (on a time-staggered basis) four times a day but have been wondering if I might be better off to put all of the chlorine into both of my outdoor pools starting at sunset. Tha little bounce might help me keep the green fog at bay a little bit longer?

 

[kimkats]

Now the evening idea might be a good one IF you know noone will go in the pool. I would make sure to test in the morning and see how the fc lasted and bump it back up to just under slam level if needed.

 

[Mdragger88]

It is safe to swim between minimum & slam level for your cya
So long as u can see the bottom of the pool for safety purposes.
The amount of active chlorine in the water at slam level is less than that of a pool with 3-5 ppm & no cya. Many municipal drinking water supplies have 3ppm fc & no cya & it is bathed in & consumed.
Here’s some info on cya & active chlorine in this video -
Key moments on the subject @2:28, 11:03, 16:43 since the video is quite long

This thread also explains the ins & outs of the subject

Chlorine/CYA Chart

EDIT: You will find a simplified and standardized version of this chart at Pool School, Chlorine / CYA Chart. Chlorine/CYA Chart by Chemgeek FC = Free Chlorine in parts-per-million (ppm) CYA = Cyanuric Acid in parts-per-million (ppm) CYA ........... Min FC3 ..... Target FC ...... Yel/Mstrd...

www.troublefreepool.com

It’s a little hard to tell from your last post- are all the pools green or just the one?
Since u are under not under the thumb of any governing body you sort of have carte blanche for how u choose to manage the pools. Managing very large pools can be quite difficult when things go awry. I understand that your superiors may have unrealistic expectations- to moderate those they should be informed of the dangers & liabilities they are subjecting themselves to by allowing an unsafe pool to remain open to the public.
The facts are:
* It takes time to clear an algae laden pool (no matter how large or small).
*There is no timeline for this.
*It is unsafe to allow swimmers in a pool when u can’t see the bottom.
*When fc is being depleted rapidly by algae & falls below minimum for your cya it is not available for sanitation this opens the door to person to person transmission of pathogens
* A pool with elevated cc’s (above 0.5ppm)is irritating to skin & eyes , often smells & is indicative of unsafe organics present in the water.

You may be correct that u will need to just “stave off” algae until u can close the pool & properly Slam.
Doing so will use more chlorine over the long term since demand will be higher than it would without nascent algae in the water.
I agree w/ Kim - do your best to hit it hard at night (or as soon as the pool closes for the day) & do not worry about lowering the fc level at opening with other chems. It will be depleted quickly by the algae, bather load, & sun. Mini nightime slams if u will. Then keeping fc elevated between high target & slam during the day.
As i stated above - it is safe to swim at fc levels at or below slam level for your cya.
Just be sure to check & balance ph when fc is below 10ppm as the ph test is invalid at fc levels above 10ppm.
Ph that’s not in the 7’s generally causes more swimmer discomfort (for skin & eyes)than a properly elevated fc level.

 

[Old Guard]

Thank you for everyone's input. What I have settled into for now is pumping in as much chlorine as I dare every night and letting the sun and bather load take it down during the day. When it starts to go green anyway, I floc it with Clorox Crazy Clarifier and vacuum like mad beginning the next morning pumping 100% of the effluent into the grass. It is expensive and time consuming, but it seems to maybe be working. High price to pay for letting the pools go to heck all winter and not SLAMing them as soon as we got all the trash out in May. We thought bumping them to a 10 for a day is all we needed to do. It did clear things up temporarily. I worry that the floc is bad for the filter and backwash every morning after.

Walking a fine line between keeping these two outdoor pools both safe and in-service.

 

[Mdragger88]

The clarifier (glue) is definitely going to gum up the filters with continued use. Are these sand filters? If so plan to replace all the sand at the end of the season.
Are these pools covered in the winter?
Now is the time to formulate your closing plans so you can save yourself some headaches upon opening. The same goes w/ your opening plans. Take advantage of milder temps & start early! How long do these pools stay open to the public?
At my mom’s place they cover with safety covers for the winter & drain & refill upon opening so they start off kinda fresh so its a little better than what u have to work with. This allows them to use pucks & things don’t quite go awry until near the end of the season. They are open from memorial day to labor day give or take a week or two.
Their pools are not that large either. They do have one swg pool but i have no clue how they really maintain it. I have seen many cases of xtra blue pucks in the equipment rooms.
With your current system, as u vac to waste & refill daily you are diluting your cya & calcium, probably a good thing for cya now but going below 30ppm cya will really up the fc consumption during the day so u will need to keep a close watch on it & replenish cya & ch.

Another thought- do these pools have lights with niches & ladders that hold water in their rails? If so, cleaning those out is imperative. It should be done each season especially if u have struggled with algae.
I don’t envy your job at all!

 

[Old Guard]

Just like your Mom's place, these pools are open "from memorial day to labor day give or take a week or two". They are not covered and do have lights, rails, slides and slide water uptake manifolds.

I've got CYA cognitive dissonance these days. A year ago, I did not know such a thing existed. Then I learned it was an absolute necessity in an outdoor pool. Then I learned that all it really does is inactivate a lot of your chlorine even though your Taylor tests still show that chlorine as free. Why is anyone using it?

Sorry my replies are slow. Working 400 to 1700 these days. My surfeit of border collies and rock-star wife (63 today) are occupying the rest of my time.

 

[Mdragger88]

Why is anyone using it?

Because without it it’s a very fine line between “we’ve got enough chlorine in the water & woops, its all gone”.
Anything higher than 4 ppm or so w/ no cya is extremely harsh & maintaining 1-2 ppm w/no cya is a constant struggle since the sun & people grime are constantly consuming fc.
Balance is key..
30-50ppm cya is the recommendation for this reason. Less than 20-30ppm, the sun is a problem- more than 50/60ppm & u need ALOT of chlorine to rid yourself of problems & to reach & maintain shock level. In a public setting there will be periodic problems- possibly daily… urine, sweat, sunscreen, fecal accidents, racoons, trash in the pool, generally high bather load, etc.
The recommendations of the FC/CYA Levels account for this & present adequate & equal disinfecting levels for each corresponding cya level.
Around 30ppm cya is probably a good spot in your instance because of the frequent need to raise to shock level for the many reasons mentioned above.

 

[Old Guard]

All four pools were beautiful this morning. What a difference a day makes. Of course, that cuts both ways. Tomorrow ... tomorrow ... tomorrow .

Thanks for the information Mdragger68. I get it.

I've got Chemtrol equipment at 3 of my four pools. Haven't fired them up because I am pretty sure the Clinton unit is deceased and new sensors for the indoor pools would cost a small fortune. We are a YMCA after all. I wonder—if I did integrate all of this—would I be better off with no CYA?

That racoon reference was particularly colorful. A gator is more likely here.

I ran some numbers today. All four pools are currently going through 16.3 gallons of industrial bleach and 4.3 gallons of acid a day. It is getting hard to stay on top of. My chemical company seems to view me as more of a nuisance than a windfall (no forklifts, no loading docks). No worries. We will muddle through somehow with all of yall's help.

 

[kimkats]

would I be better off with no CYA?

Nope as you will have to be adding FC all day long to stay ahead of the sun and people *stuff* added to the pool.

 

[Mdragger88]

U definitely need some cya - or u will be really rolling through the chlorine like Kim said. The key is definitely balance. 20-30ppm is probably a good idea - enough to keep the blistering sun from eating all your chlorine but low enough that shock level is still easily attainable. Maintaining target fc levels for your cya based on the chart gives u a good buffer for all those person to person transmission incidents I mentioned earlier without allowing u to fall below minimum keeping the water sanitary & safe. Maintaining 1-2 ppm with no cya in southern MS is like walking a tightrope - not fun & it can get risky fast.
Too funny about the gators .. Just got my email from MWPF about permits today & u are definitely in gator country down there!
Glad things are looking better but don’t let it fool u - nascent algae is likely still consuming your fc leading to the high demand. Keep chipping away at it & hopefully u will be able to keep the green monster at bay until u can truly eradicate it when you shut down. Doing Overnight Chlorine Loss Tests should help u get an idea of where u stand in the battle as go along.

 

[jedigrover]

This is a perfect example of the issue we have here with Clarifier.
1) Nobody reads the instructions on the bottle.
2) The pool store sells it as a cure-all.

Regarding (1)...most clarifier that I have seen has a dosage something like 4oz per 10,000 gallons. So a 125,000 gal pool would need 50 oz...just over 1.5 quarts (not 3). It says right on the bottle that adding more will have the exact opposite effect of what you are hoping it will do. Too much will cloud the water.

So pool stores sell someone with a 20,000 gallon pool a quart of the stuff. They need 8 oz (and probably should use a little less to be safe), but they don't read the bottle & dump the whole thing in. Pool store knows they're going to do this. The water either doesn't clear or gets worse. So they return to the pool store and tell their story. The pool store tells them they need "enzymes" to "eat up all the stuff" and happily make the cash register ring again.

I have used it when all of the following conditions are true:
1) I have killed the algae and confirmed this by CC <= 0.5 and Overnight Chlorine Loss Test passes with less than 1ppm lost overnight.
2) pool is still hazy
3) I plan to do a deep clean of my filter within a couple of days anyway.

Then I dose it at maybe 3/4 what the label says and deep clean the filter within 2 days, running the filter 24/7 while that's going on & watching closely for any large pressure rise. When used in this way (what I consider properly), it helps speed up clearing the water. I do not use it any other time. I have never and will never use floc unless a mud meteor lands in my pool. And in that case, I'm probably going to prefer a full drain and clean up to floc.

Aside from speeding the clearing of haze after killing an algae bloom, clarifier has no use. Properly balanced water will be crystal clear without its help.

To the OP: you can save a lot of money by getting some CYA in the pools, abandoning the clarifier / floc and sticking to proven methods you will find here. Commercial pools are a bit different due to potential regulations on chemistry levels, but I don't think they are so different that it warrants a wholesale different approach. Maybe just figuring out when you can or cannot dose things in.

 

[Old Guard]

Both my outdoor pools have reasonable levels of CYA in them. I haven't tested them lately but am sure they are >25 <50.

The routine I am now following is to start pumping chlorine at sunset and letting it run as long as need be to get an opening value of ≥ 5 PPM. The sun and a few hundred kids knock it down to 2-3 PPM by sunset. My biggest pool is getting 9 GPD of 12½%. I just went and dumped an extra six gallons in that pool out of a bucket as it was beginning its days 3ish PPM of late. I have not needed floc for days. Hopefully that is behind me for the summer but—when the bottom of the deep end disappears—floc is an overnight miracle, so I have some on the shelf. We have settled into backwashing 24 hours after floc administration and vacuuming.

 

[IceShadow]

I have to wonder if you wouldn't be better off with some sort of chlorine gas system to introduce chlorine to the pool in a commercial setting. (Something I've only heard about, mind.)

 

[Old Guard]

I have heard of that too but know no more than that. Our current system is working fairly well and only requires a pump that costs a few hundred dollars for each chemical in each pool. The biggest headache is making sure you don’t run a barrel dry before you change it. My 400,000 gallon pool is going through a barrel of chlorine in less than a week.

Fingers crossed but my two outdoor pools have been crystal clear without flocking for more than a week.