First Time SLAM question

[jdlw]

Hi, I’m starting toSLAM my pool for the first time as helpfully recommended by a member here. (CC climbed toover 2ppm in the week after opening my pool). I think my TFT100 test kit will arrive either today or tomorrow.
I’ve read pool school and numerous recent posts on SLAMingbut I have a few questions.
-I’ve seen cases herewhere people have had to maintain shock level for up to a month. How long does it take before the liner startsto fade because of the higher levels of FC?
-Should I spread all that Clorox throughout the deep end orshould I just pour it in front of the two jets in the deep end? (that’s what Idid yesterday, but I started to think that even though there are jets there,that after many days /years of doing that, the liner there might age/fade morequickly?
-Is it Ok to use my Tigershark for the daily vacuum and to brushthe walls? I clean the Tigershark filterin between with water.
-Unlike most of my neighbors, I was lucky not to have agreen pea soup pool when our winter safety cover was removed (warmer winterthan typical in upstate NY). Our water looks clear. However Idid notice some golden/brown crust on the liner along the water line when we first opened (I brushed the liner so it's not visible anymore). I’m wondering if that’s the mustard algae I’veread about? Is there any downside tofollowing the pool school protocol for mustard algae just to be safe even if I’mnot sure if that’s what it was?
Thanks so much! Wish me luck : )

 

[bobodaclown]

Hello,
Congrats for taking control of your pool and not getting "pool stored". It's nearly impossible to tell when you'll notice the fading. Remember you let the CYA level determine your shock level, that being said, having a FC level at 10 and CYA of 30 is not the same as having as FC level of 10 and CYA of 10 (10/10 chlorine will be more aggressive then 10/30). There are charts that show this in the post (advanced reading).
Doesn't matter really. The flow of water will mix it up pretty quickly. (If you want to mix it quicker, brush down the sides of the pool, it will do good things for the pool, mixes and cleans).
Sure you can use the tigershark, but really nothing is better than a good brushing and vacuuming.
It may have been just crud accumulating from the season. No downside except wasting bleach if it isn't. Follow the normal SLAM procedure for now. Do a little more research on mustard algae to confirm.

You're on the right track!

 

[tim5055]

As long as you remain at shock level or slightly above there is little chance for liner fading. The biggest threat is as you point out, pouring in one spot and the chlorine not mixing well. We recommend pouring slowly in front of a return and then using your brush to brush the wall, floor of the pool under the spot you added it to make sure it is mixing well.

If you have clear water, but high CC and maybe a OCLT fail I would not hank you are a candidate for a month long SLAM unless you don't adjust back to shock level multiple times a day. The long ones are generally folks who through scheduling issues or motivation issues don't stay on top of the testing and adjusting back to shock level multiple times a day. Plus, remember you need to brush the entire pool once a day to allow the chlorine to get through the biofilm that some algae has as a defense mechanism.

 

[kcindc]

More than likely you just have plain algae and not mustard algae. Regardless of what you have, you need to SLAM first. After you complete the SLAM we can revisit to see if you have mustard algae.

You have a DE filter and your water isn't in too bad of shape , so I think you will finish very quickly... a week at the most and a couple of days if you really stay on top of it. Make sure you backwash when your pressure rises 25% above the clean pressure. DE filters can clog quickly when clearing algae so don't run it all day at first without being there to check the pressure. As you get further along, you will have less frequent backwashes.

It is up to you on using your Tigershark... just make sure you don't overshoot your FC because if you accidentally exceed your FC/CYA SLAM level it could damage the robot. You definitely don't want to keep your tigershark in the pool when you are not using it. As mentioned above, regular brushing and vacuuming are the best method during the SLAM.

 

[jdlw]

Thanks Bobodaclown, Tim and Kcindc!

Levels before unofficial shock and SLAM (per pool store):
FC2.88
CC2.07
pH 7.6
Alkalinity 69ppm
Hardness 157ppm
CYA 29ppm
Phosphate 711ppb

My test kit arrived yesterday so I'm finishing my second official day. In reality I unofficially started a little earlier using the pool store numbers. I only had daily testing so I wasn't able to perfectly maintain shock level on Tues/Wed, but it did help because my CC that had been 2.07 earlier in the week was down to 0.55 when I started the official SLAM yesterday. Fortunately I was able to work at home and make frequent adjustments today and yesterday. CC was between 0 and .5 by this morning so I'm going to do the overnight test tonight. It might be thrown off a little as I let the FC fall below 12 this afternoon since my husband invited a few people over to swim. However, I tested after they left and didn't see CC in the pool after they left and I brought the FC back up to shock levels after they left. We shall see.

Question: Assuming it does pass the overnight test, I will need to bring CYA up to 70. Should I immediately add the CYA or should I wait until FC falls closer to the targeted FC of 5ppm for a SWG pool with CYA of 70?

Thanks!

 

[Texas Splash]

If you pass the OCLT, the water is clear, and CC less than 0.5, then yes you can begin to increase CYA right away. Keep a close eye on the FC production of your SWG to ensure you stay in that ideal target zone. Confirm CYA in a couple days. But definitely make sure you continue to clearly pass all 3 criteria while the CYA is low just in case you need to maintain the FC of 12 for another day or two. Best to save on bleach now while your CYA is lower. Good luck!

 

[jdlw]

Pat, very good point to closely monitor all 3 SLAM targets while I bring CYA up. thank you.

I tested the water early this morning (I HATED setting my alarm for before 7am on a rare day I could have otherwise slept in...but then again, after being obsessed with chlorine readings and adding chlorine the past 4 days, I was having weird restless pool water dreams anyway haha)

Anyway, I had measured FC at 12.5 last night and 13ppm this morning. The pool had been circulating for well over an hour after any Clorox additions before I took the reading last night so FC shouldn't have gone up. Do you think it was just acceptable margin of error? or did I make a mistake measuring FC, I wonder. In any case, I'm going to do the test again tonight to make sure. The water stayed clear when I did the CC test (i.e. below 0.5), however I took my water to the pool store today and their reading for CC was .44ppm...so closer to .5 than 0. When I bring CYA up , it will be harder to SLAM the pool. Given that, Is CC less than .5 (or .44)good enough or should I try to lower it closer to zero?

I still have the SWG turned off - even during the day - because I want to start to get my CYA levels much higher before I use the SWG. I had such trouble keeping pH down last year and even earlier this season. I've never had consecutive readings where pH hadn't climbed until I turned the generator off. So I'm still manually adding Clorox to keep FC up. Today was sunny and 90 degrees and I was SHOCKED how fast the FC dissipated...it fell nearly 4ppm in 5 hours . It had been cooler and cloudy when I was originally SLAMing the pool and FC lasted longer! I feel like thanks to all of you , I am just starting to understand how it all works (still have tons to learn, but it's a start)

I put a tiny bit of CYA in earlier today. It was an amount the calculator said would raise CYA to to 35 so tonight I also brought FC levels up to 15ppm (I slightly overshot the 14ppm I was aiming for)

(P.S. I'm not taking the pool stores advice on what to add or what not to add, but I'm trying to see if my measurements come close to theirs. If my readings and the store's readings do seem to validate each other over time, I might use the pool store's readings every week or so to supplement mine or at times that I'm tied up or out of town, my husband can go to pool store and report the results to me)

 

[Texas Splash]

Yes, a CC reading of 0.5 or less is treated as zero here at TFP. So you're good there. You sound to be doing everything right, and the fact that your FC went from 12.5 to 13 last night/this morning might just be a testing variance. You have the best testing products available (TF-100), so I wouldn't bother having the pool store validate your numbers. It might just drive you crazy. The only time I might understand someone getting their water testing done at the pool store is if they needed to have documentation on-hand for their warranty, or perhaps for metals testing. Before too long, you'll walk into the pool store, listen to what they tell customers about their water, and scratch your head saying ... "What?"

 

[jdlw]

Thanks, Pat. I don't doubt the TF100...I doubt the user! (is the water truly clear? Which color does the ph match? etc etc. confidence will come with time and you guys helping me!)

Did OLCT again last night and passed so this SLAM is truly officially over! Starting to work CYA in but now have some other questions on other tests. I'll start a separate thread for those. THANKS SO MUCH for everyone's help!

 

[jdlw]

Next step after SLAM?

I just finished my first SLAM (http://www.troublefreepool.com/threads/116568-First-Time-SLAM-question ) and have started to slowly bring up the CYA levels.

This is the first time I used my new test kit (other than FC/CC) and the results were:

FC - 10ppm (quickly falling in this heat)
CC - 0.2ppm
ph - 7.6ppm
TA - 70
CH - between 400 and 425
CYA -approx. 35 - plus CYA added to bring to approx. 40. Going to make next addition but wanted to ask question first.

- Should I partially drain pool to bring hardness down or should I allow it to happen naturally with splash out and refill. I'd prefer to avoid if possible since pH of our fill water is 8 or 8.1 and I struggle with pH. BTW, CH is very different than the readings I got at the pool store on their spin thingy for "total hardness" which provides yet more evidence that store readings can be bad. Pool store readings for hardness this year have been approximately 150-160. Thank goodness I found this website before I added the 28 pounds of calcium hardness they recommended! (and I already bought, doh!) I think this also explains part of my problem last year with white flakey things (scale?) floating in pool. If pool store readings were similarly inaccurate last year also, when I thought my hardness was 200ppm+, it was probably closer to 500.

- Should I bring pH down a bit before getting CYA up into the 70s (will it be harder to adjust pH after CYA is high?) I ask because I have TOTALLY struggled keeping pH down over the whole last season. I was in a cycle where I would add MA last season to bring pH from 8 or so down to 7.6 or 7.7 and it would be right back up there again within a couple days. Then TA would fall too low from all the MA and when I added baking soda, pH would come up a bit (although I have more leeway this year since I see the pool school guidelines that TA of 60 is OK for a SWG pool) etc etc.

Thank you!

Mod note: I merged your two threads to keep the whole story together.

 

[YippeeSkippy]

Re: Next step after SLAM?

Being in NY with snow and rain in the winter you could use that to your benefit in water replacement over time.

Until the calcium is lowered, just keep your pH at the lower end of normal (7.2-7.4) and monitor your CSI on PoolMath and you should be okay.

Does your pool have water features or fountains that cause a rise in pH? If so I would avoid using them too much (yet some daily to avoid stagnant water to sit in the pipes)

CYA has no effect on pH.

 

[duraleigh]

Re: Next step after SLAM?

What is the CH of your fill water?

 

[kcindc]

Keep your chemistry questions on the same thread. It will be easier for us to give you info when we know the background of you and your pool.

Sent from my SCH-I545 using Tapatalk

 

[jdlw]

Re: Next step after SLAM?

Last year I had fill water tested at pool store and the result was 114ppm...but obviously I don't trust it in light of the above...so I just tested it myself and came up with 200. Last year the pool store tested our rain hardness at very low levels so rain water would be preferable. Towards the end of last summer when I was having trouble with scaling and they suggested lowering TDS might help, I had taken advantage of any big rain falls "dilute" the water. I lowered the pool more than usual before closing and it was refilled by winter snow/rain. That probably accounted for 1 1/2 feet or so (and is why my hardness levels are measuring lower this year compared to last...albeit incorrect and underreported numbers if I didn't make a mistake).

Is it possible the reading is wrong since I hand swirled instead of using the magnetic stirrer?


If my reading is accurate, this is one of those classic pool store stories you warn us about! And in hindsight, I do remember the scale last year came suddenly after I made a pool store recommended addition...I think it was calcium hardness! I haven't really seen the floaty white dandruff like things recently though.

 

[tim5055]

Yup, keep it here. It will save us from having to move it

 

[duraleigh]

ditto that...keep it here.

 

[jdlw]

Re: Next step after SLAM?

is CH a test that can be thrown off when FC is at or near shock levels?

 

[Richard320]

Re: Next step after SLAM?

is CH a test that can be thrown off when FC is at or near shock levels?

Not in my experience. The pH test gets wacky and TA goes from green>pink to blue>yellow.

That being said... CH takes a whole lot of swirling. I use a speedstir and my CH dropped 200 points just by switching methods. Sometimes when it's sitting at the purple stage, another cycle of the speedstir without any more drops will push it over the hump into blue.

 

[jdlw]

Re: Next step after SLAM?

OK, I'm guessing my speedstir piece should arrive Tuesday. I will recheck the CH levels then.

 

[jdlw]

Keep your chemistry questions on the same thread. It will be easier for us to give you info when we know the background of you and your pool.

OK, sorry about that! I didn't know if it would make this thread to long and onerous. But now I know! (another thing I've learned )


So my speedstir piece arrived today and I remeasured CH. It's a little lower, but not much. It's Somewhere between 350 and 375. Can I wait that out? (i.e. drain an inch or two before a rain storm throughout the summer? Or when I top it off after a backwash? (although fill water at 200ppm is harder than our rain water)

Thanks!