New pool, green water, SLAMing, FC rose overnight

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rwood5093

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Jun 5, 2016
86
Jamestown, SC
It took us several days to get our pool full and up an running due to a vareity of issues.

By the time it was full, it had turned a slightly cloudy green.

All I had done at this point is fill (over 3 days+) and add 1/2 bottle Poolmate Mineral out (Brown bottole) since we know we have iron and it was starting to rust almost immediately.
We also added 120# of salt, per the intex SWG manual and 1.3# of CYA per the manual (which seemed low). we then ran the pump for 24 hours.


We used our K-2006 and K1766 (salt) tests and came up with the inital results.
ph = 7.2
Salt = 3000ppm
CYA = 0 (not totally shocking since we just added the CYA 24 hours before)
CH = 200
TA - 190
FC = 0
CC = 0

We entered these values into poolschool and came up with the following action plan (intending to SLAM due to the green water):
ph = leave for now, since the TA was 190, and the target range was 60-80. recommendation for TA was to drop the ph to 7.2 and aerate. since our ph was already 7.2, we did nothing.
Salt = added 6# to bring it up to 3200
CYA = poolschool said to use 47oz. I subtracted 21oz that I added the day before and added 26 more oz, in a sock tied to a pool float.
CH = no action at this time
TA = keep the ph at 7.2 and aerate
FC = add 63oz. liquid 10% bleach

turned the pump on and the SWG (might have been a mistake, but we figured extra clorine wouldn't hurt)

We tested 4 hours later (after dark) FC = 12.5

Tested this am and FC = 13. The filter cartridge is pretty gross due to the iron that its filtering out and the water doesn't look a whole lot different. I can barely see the squares on the bottom of the pool.

Based on the criteria to quit the SLAM
You are done when:

  • CC is 0.5 or lower; - check
  • You pass an OCLT (ie overnight FC loss test shows a loss of 1.0 ppm or less); - check - maybe?
  • And the water is clear. - FAIL


So, with all that said,
how bad did we mess up by using the SWG while trying to SLAM? could it produce more clorine than the algae would consume overnight? I guess we're not sure if we really have an algae problem, or if it could be some type of metals issue that's not covered by the Mineral out.
Is it normal for the CYA to read 0 24 hours after adding it? I see the note that it could take up to a week for it to fully dissolve, but I thought it would have registered something. My first addition was only 1.3#, which seemed weird. the CYA that I added in the sock doesn't look like it's dissolving very fast.


Are we on the right track? Should we turn the SWG off for now, keep SLAMing and just filter do it's work? We will probably vaccuum the bottom this weekend. but then we'll have to add more water, more mineral out...

Thanks for any advice you might offer.

Robin
 
Yes, SWG off when SLAMming.

CYA will register within about 24 hours of dissolving. If the socks aren't dissolving fast squeeze them to help them along.
 
Robin, Mr Bruce has you covered on the SWG and squeezing the sock(s) to help the stabilizer dissipate. I just wanted to make sure you had the TFP Pool School - Metals in the Water and Metal Stains page/link for future reference. Keep-on SLAMming until you pass the 3 criteria, then we can focus on the metal situation. And since your pH is good at 7.2, don't worry about anything else right now other than FC, CC, and validating your CYA later today (under bright sunlight). Get rid of that algae and cloudiness first, then you can focus on everything else. Good luck!
 
So, the SWG has been off most of the day.

Thanks ya'll. At 4 pm, the FC had gone up to 14.

Tested again after dark and it's 17. FC was 1.

We haven't added any chlorine since yesterday since it's over 10. I did massage the sock until the entire glob of CYA dissolved into a milky white cloud. Will test tomorrow.

The pool looked slightly worse... The filter was very brown with rust so it got rinsed too.

I'm so bummed!
 
since the CYA in the sock totally dissolved last evening, I tested the CYA this morning and came up with 80.
FC had dropped from 17 last night to 13 this morning, and we got a CC reading of .5
I had been using 10 as my SLAM target becuase the CYA had measured 0.
Based on the Clorine/CYA chart, my SLAM FC target should be 31, right?

So, if FC has been around 13-17, is that part of the reason I haven't seen any change in the pool water? Once I get it up to 31, things should start moving in the right direction, right?

Thanks for the advice.
 
Good morning Robin. I had to take my time and really pick-apart your descriptions from post #1 until now because something had me concerned. In the beginning, you did a great job describing everything that you had done and previous readings. While you mentioned a history with metals, your primary issue seemed to be green water, so we were focused on the SLAM, turning-off the SWG, etc. But now the only thing that has me concerned is how high you are taking your CYA. For a SLAM, we try to keep that number low until the SLAM is done, then increase it as needed. That way you use less chlorine (bleach). But in your case, less chlorine might also mean less chemical reaction to the metal. The higher you increase FC, the more chance of metal precipitation and pool staining. Your last post shows a CYA of 80 which does require a much higher FC SLAM level, so I'm worried about what might happen once that is increased. Does that make sense?

Now I want to be sure of something ... your pool size. The Poolmath calculator say a 16' round by 4 ft deep pool is about 6000 gallons. Is that what you show on your end? Because in post #1 you stated adding 47 ounces of stabilizer, so in a 6000 gal pool that would make the CYA about 60. So at this point I'm more concerned with not only how high the CYA is, but what reaction may take place when the FC is increased.

Give this a moment to process and give me some thoughts so we can make sure you take the right steps forward.
 
Hi Pat, thanks for your response.

I am using 5061 gallons for my pool size based on the 90% figure from the intex pool manual. We have the Hayward skimmer installed and I thought that number sounded reasonable.

So when I used that in the pool calculator, I was trying to get the cya to 70. It suggested the 47oz of Cya. I had already added 21oz the day before, so I added the extra for a total of 47.

I didn't read the cya outside. I read it in my living room under a Led light since it was 5am. I am not ruling out an error in my reading and I will redo when I get home this afternoon, outside. I asked my husband to read it and he said 100, but his eyes aren't as good as mine. If I get some thing different, I will redo my pool math.

I totally understand what you mean about the metal interacting with the bleach. In a cup of tap water, even a few drops of bleach turns it black. We had no change when we added the bleach the other day so I felt confident that the metal out was doing its job.

I will check the cya again and report back. The vacuum is coming today, so if I need to lower the Cya, I can always try the vacuum out.

Thank you!
 
You don't want to bring up the CYA until the SLAM is completed. Lower CYA is better for SLAM. Less bleach/chlorine. You raise CYA after your water is clear to aid the SWG & retaining FC during the day. The CYA test needs to be done outdoors with the sun at your back, tube held by two fingers at the top of the tube, waist high, looking down into the tube. You can just pour the water back and forth between the mixing bottle and the tube a couple of times to get a better result. You might want to look into the tube, look away and look back to get a better reading. Sometimes I think my head is the dot in the bottom. You could try filling the tube to different lines and see if you can see the dot, because you round up the the next higher line when the dot goes away. I bought the 50 CYA sample this year just to verify I am seeing the test correctly. Now all I need is a nice sunny day and time to do it.
 
Understood (now) that the Cya should have been lower for the SLAM. But it's already done. Do I need to drain to bring back down while I continue the Slam or just stock up on chlorine and deal with it?

The original plan was started before the green appeared. We started on the Cya, then changed course to Slam when it turned green, but didn't halt our Cya process like we should have. I guess there was some confusion on our part too since the Cya was 0, and our initial target of 70 wasn't modified down when the green showed up.


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Since your pool is not too terribly large, I would recommend a partial water exchange if you can do it. Even if you only do half and get the CYA back to around 50 or so, that will be much easier on you and the bleach required. It might also help with that metal content if you are able to do any additional pre-filtering before the new water gets into the pool. Lastly, a lower CYA means a lower SLAM FC level which may help prevent the interaction between chlorine and metals.

- - - Updated - - -

I always round-up CYA. So if I get 75, I call it 80. If I got just barely over 70 (i.e. 72-74), I call it 70. :)
 
Not to be hard headed, but why can't I treat it with the Cya being 75? Will the bleach not work chemically? Will it take longer? Would that much bleach be cost prohibitive? Etc.

I'm just not excited to drain it. I don't have any way of filtering the incoming water and refilling halfway is a pretty big hit on our shallow well. Plus another bottle of metal out which will not get here until Tuesday.

I'm just trying to fully understand. I appreciate your wisdom and advice.

Robin

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That's okay. You can still SLAM at 31. The CYA tube is in increments of 10, and we don't try to split it up between numbers. It just becomes a tricky mess that way. But you can try the FC of 31, or at least increase FC slowly about 10 ppm at a time to see how your water reacts. If it does okay, continue with the FC of 31 and SLAM. If at some point the water reacts extremely bad to the high FC and metal begins to precipitate out onto the pool, you'll know you may have no choice but to exchange some water. So at least you tried. Thoughts?
 
We were slamming at 31 for 24 hours and decided to do a partial water change. Dropped it 8 inches which brought the Cya down to 60. Refilled, and have maintained appropriate FC level. FC has been good at dark and falls about 5 overnight. We add bleach in the am to jack it back up. Been at Slam level for 48 hours. Not a whole lot of change in the appearance, but you can almost tell there is a 2nd step on the ladder.

Since adding the new water, I am rinsing the iron out of the filter every 2 hours.

Hubby had to go in because the net disappeared and the only thing we thought was that it fell in the pool. We couldn't see the bottom, so he had to in and feel around. On a positive note, he said it feels like a pool, smells Like a pool, and if you close your eyes you wouldn't know any different. :)

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The CYA test can be affected by turbidity(suspended solids in your water) indicating a higher reading.

You have insoluble iron in your water supply, buy some inline garden hose filters for filling the pool in the future.
in the mean time this small pool is a prime candidate for flocculent - cheaper & faster under the conditions you have

Fill your pool as high as possible, keep the FC up. Add "drop out" "flocculent" as prescribed circulate for a few hours, while doing this fill your vacuum hose and have is set ready to vacuum leave it in the pool.
Shut down the pump leave undisturbed overnight.
You should have a nasty cloud of crud in the bottom the next morning

Change your fittings to vacuum to waste, and gently vacuum while refilling.

You should have a clear pool in under 36hrs.
 
Would I see this in the filter?

The FC is falling 4 to 5 ppm overnight. Isn't that a sure sign algae is raging?

One difference since lowering the Cya is we are rinsing the paper cartridge filter every hour or so. It's pretty orange (like my clothes that used to be white) each time..

Is there something chemically happening now that wasn't happening when the Cya is higher? It just seems weird. But at least there are no rust stains in the pool.



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rwood this is a brand new pool filled from a high iron content well correct?
You are probably seeing more insoluable iron in your pool than algae. Normally folks with dissolved iron are unable to filter it, yours is already oxidized and is large enough for the filter to stop it.

here's some youtube videos on how some DIY folks removed their iron problem
https://www.youtube.com/watch?v=vC1wAkGC_PI
https://www.youtube.com/watch?v=_mwFkSbSf54&spfreload=10

If those are too difficult to build flocculent will drop the suspended iron out along with any dead algae, then you can restart the SLAM.

as for your CYA question it does two things
1. filters UV rays from penetrating the water and breaking FC from your water into the atmosphere
2. Bonds with FC to form larger chlorinated isocyanurates which filter UV but breakdown to release FC.\

When CYA is high there are more molecules grabbing FC to come to equilibrium leaving less FC to fight the algae & bugs
 
Thank you! I will watch the videos in the am. I watched some pretty inventive ones earlier today. Some of them were pretty interesting...

Yes ma'am, it's a new pool. We have enough iron to require a pur filter to drink. We sent our water into DHEC almost 2 months ago, so while we know we have iron, we don't know exactly how much yet. A cup of tap water will turn icky in less than a half hour, but I have no idea how that translates on the 'high' iron scale. We used the poolmate mineral out when filling the pool and haven't seen any stains like we expected. I had very slight staining when there was one inch of water, but I added the mineral out, brushed the stains and haven't seen any since. That had us thinking that the mineral out was doing its job.

It took us 3 days to get it filled and another to get the filter running. It was pretty clear until about the third day. Then we started down the path of new pool setup, but apparently it was too late and we turned green. This was last Thursday.

I didn't phrase my question properly. I understand the Cya chlorine concept, but wasn't sure if the lower CYA/chlorine combo was reacting different than when the Cya was 80.

Thanks for the tips and info. Hopefully I will be swimming soon.

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We have a third step! The 5 gallon polyfill bucket has been running since 1830 last night. It worked out great, we were able to use the extra eye that came with the Hayward skimmer as the inlet to the bucket so all we had to buy was the bucket and poly fill.

Yes! Thanks guys. There might be a blue bottom down there somewhere.

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The bucket worked! After 24 hours , the pool is almost crystal clear. We finally cut the liner for the skimmer, cleaned the bucket, vacuumed the bottom and got it all setup to filter for another day.

I ran out of FC test reagents yesterday, but should get more tomorrow. We passed the overnight test yesterday, so hopefully I've maintained FC high enough over the past two days that we can end the SLAM.

Tomorrow we are going to do a full set of testing and see where we need to go from there and maybe even get the SWG running. I am sure the filter will enjoy some downtime as its been running 24x7 for 9 days .

It's been 10 days total. Now I just want to float around and smile at the sparkle.

I can't thank you guys enough! You rock!

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