New house, green pool after salt conversion

grunky_peep

Gold Supporter
May 26, 2020
27
Sacramento, CA
Hello TFP, first post here after reading regularly for about a month.

I just purchased a home with a pool, so I'm a complete pool newbie. It was traditionally chlorinated, and had old junky equipment and half of it was broken. I had a pool company come out to get me an estimate on replacing basically everything, and do a conversion to salt. At the beginning, it wasn't crystal clear, but definitely wasn't green; I'd say it was slightly murky. He didn't give me any specific test results, just said it was safe to swim in for the time being. Good enough for me, and my kids were happy.

Anyway, they came out 3 days ago, replaced the pump, booster pump, pool sweep, pool light, spa light, added a SWG, and dumped a bunch of salt in the pool as I lit a pile of money on fire. I tried to capture all of the equipment in my signature. My pool is a blob, so it's hard to get the exact capacity. The pool guy estimated it as 18-20K, including a ~1K gal spa. He said to run the pump for 24h to dissolve the salt, then plug in the SWG. I did exactly that, and 48 hours following the install (and 24h since the SWG was powered on @ 70%), the pool is now a murky green (pics attached).

Since I have exactly nothing on hand, I went to Leslie's (yeah yeah, I know). They tested my water and came up with:
FC = 2.0
CC = 0
pH = 8.0
TA = 120
CH = 150
CYA = 55
Salt = 3800
Temp = 80'
They said it looked pretty good and was still safe to swim in, but gave me some Muriatic acid to drop the pH, and some Calcium Hardener, as well as tried to upsell me on a bunch of other weekly chemicals. I declined those and took home the acid and Calcium Hardener. I plugged my test results into Pool Math, and it said to drop the pH to 7.6 I'd need 22oz of 31.45% Muriatic acid, so I did just that and ran the pump for 4 hours.

Amazon delivered my Taylor test kit later that night, so I just did my first test this morning. My complaints about the titration tests aside (is it red? is it pink? it was clear, but oh wait, it turned a slight shade of pink 20 seconds later, etc), I came up with the following.
FC = 4.0 -- This test is tough for me since it seems the titration turns the sample clear, but it'll come back to a suuuuper slight pink hue 20 seconds later after sitting. Should I be adding drops until it can sit for, say 30-60 seconds, without turning from clear to pink?
CC = accidentally dumped my FC test sample before reading the directions for this test, oops
pH = 7.8
TA = 140
CH = 190
CYA = 48
Salt = salt test kit comes later today, so no reading yet, but I wouldn't think it would change much from yesterday
Temp = 82'

I've been trying to read up on the order of balancing. It sounds like I should try to tackle pH/TA first, then the rest. Pool Math says to reduce TA, to drop the pH to 7.0 - 7.2, and for me to drop to 7.2, I should add a whopping 82 oz of Muriatic acid. That could totally be right, but it sounds like a fairly large number. The sheet that Leslie's gave me said to not introduce more than 29oz of acid at a time, and to do it in chunks of 29oz, run pump for 4 hours, then do another chunk. So, I just dumped 29oz of acid in and kicked the pump on, and here's where I am now. I'll do another pH/TA test in 4 hours.

So, I suppose my questions are:
- Is it correct to tackle pH/TA first?
- I've read that low chlorine and also high TA can cause a green/murky pool. Is that correct?
- My question above regarding the FC titration test and the shades of pink.
- Anything else to blast my green away? How long am I looking at to make my kids stop asking me 30 times a day why our pool is green? :)
- Is there a best/cheapest place to buy chemicals online, or do I just suck it up and buy at Leslie's? It seems like Amazon has Muriatic acid for way more than Leslie's sells it for.

I've been reading ABC of pools and the Pool School stuff as much as I can, but there's so much info it's hard to retain everything, so I apologize if my questions were answered there! These forums have been a great source of info so far. Thanks for reading my wall of text!

edit: I forgot to add, we have a MASSIVE oak tree right next to the pool. Despite it providing a ton of shade, no matter how much I have my kids skim with the net, there's always oak leaves in the pool! There's 1 skimmer in the shallow end, and I just installed a weir door on it. It gets some of the leaves and junk, but definitely not most of it.
 

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mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
30,942
Laughlin, NV
Welcome to the forum!
Once the FC test turns clear, test is over. Immediately go to CC test. If sample left to sit, it will turn pink again. Dispose of the test once it turns clear.
Lower your pH to 7.2 and follow the SLAM Process. Your SLAM level FC is 20 ppm.
You can get all your chemical needs at Walmart, Home Depot, Lowes, etc. If you have a HASA dealer they may have liquid chlorine and muriatic acid. As you have a SWCG, you will not need much liquid chlorine after you finish the SLAM. The SLAM will take at least 5 gallons and most likely more.
I suggest you read ABC's of Pool Water Chemistry.
 

grunky_peep

Gold Supporter
May 26, 2020
27
Sacramento, CA
Quick question: will the length of the SLAM process be affected by the GPM setting on my pump? Is there any advantage to setting it higher during the process, or should I just keep it at the default 30 GPM?
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
30,942
Laughlin, NV
No real advantage. Low RPM is fine. 1200 rpm is normal for most pools using liquid chlorine.

Brush Brush Brush. Vacuum at least once per day.
 

grunky_peep

Gold Supporter
May 26, 2020
27
Sacramento, CA
Re-did tests last night prior to beginning the SLAM.
FC = 0.5
CC = 0
pH = 7.2
TA = 100
CH = 190
CYA = 45
Salt = 4400

Since my CYA changed (or more likely, I did the test more correctly this time :)), I have a target of 18 FC, which Pool Math told me was 3gal 1 qt. Accidentally over-poured and ended up with 3.5gal of 10% chlorine. Oops. Brushed, and let the pump run overnight.

This morning, I did another test:
FC = 0.5
CC = 2.5
CYA = 45

I was shocked at the FC test. I had to re-do it a couple times since it barely turned a light shade of pink after 4 scoops of powder. Seems like all the FC was used up overnight. Pool is still a murky greenish (wasn't expecting otherwise, I know this takes a while). Anyway, after plugging the numbers back in, Pool Math told me to add 3gal 1qt again, so I did early this morning. Brushed, emptied filters, skimmed, and here we are. The waiting continues. I'll probably do a FC/CC test at lunchtime.

edit: I'm already ordering more testing reagents online since I seem to be blasting through the FC/CC and CYA ones.
 
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mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
30,942
Laughlin, NV
If the pool is green, test FC and add liquid chlorine every hour or two. It will use up the chlorine fast to start.
 

carnivalday

Gold Supporter
Bronze Supporter
Oct 25, 2017
578
Ocala, FL
Your CYA is either 40 or 50. If its between 40 and 50, round it up to 50. The FC/CYA chart seems down right now, so I cant tell what your SLAM level is for 50 CYA. Hopefully it will be back up soon.
 

grunky_peep

Gold Supporter
May 26, 2020
27
Sacramento, CA
Ok, I'll round it up to 50, which is 20 FC (the chart is one of my 20 TFP tabs open :p)

And wow, 3 hours after I added 3gal 1qt this morning, I did another FC/CC test.
FC = 0.5
CC = 0.5

This is some crazy hungry algae! Just added another 3 gal 1 qt. I'm going to be buying Home Depot's complete stock it seems.
 
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