Old Pool and inexperienced owner - Need help

[Jamestown101]

I've been attempting to maintain my pool over the last couple of years relying on test strips and pool store advice with not great results. This year I'm trying the TFP philosophy-approach. Any advice would be greatly appreciated. Here are the details about my pool:


My pool is 36,000 plaster, 30+ years old and in the Northeast, the pool is very deep it was built by a diver.

Struggling with the yellow algae you see it in the picture.

In the past I have struggled with chlorine lock and had to drain and add fresh loads of water or over shock to break the lock. This is a major concern of mine as I contemplate doing my first slam. Our swim season is short and I can't use our well water to fill and fresh water delivery is difficult to get, so I'm worried about creating a chlorine lock with my first slam.

Just received my new TF-100 test kit. Here are my results from today:
PH = 7.2
Ch = 5/10+ (solid yellow)
FC = 8.5
CC = 0
CH = 275 ppm
TA = 80
CYA = 50

I couldn't figure out the pool calculator. Any advice on raising my TA? Any advice on slam given my concern about chlorine lock and of course any other advice would be greatly appreciated.

Thank you!

 

[clambert1273]

Welcome to TFP!! First no such thing as chlorine lock. Let's get you reading & learning on how to have trouble free pool!

Pool Care Basics
FC/CYA Levels

And get this to use!!
PoolMath

We'll be here to help in the process!

TA is fine, leave it be.
SLAM Process
Overnight Chlorine Loss Test

Results!
How Clear is TFP Clear?

 

[Jamestown101]

Hi Clambert,
Thank you for your reply! Could you help me understand how much bleach I should add for my first SLAM. CYA 50 / FC 8.5 and bleach 7.5% The pool calculator says "your target is outside the recommended range" and at the bottom (5 gallons/1 quart and I'm confused. That seems like a lot of bleach to dump into the pool? How much more bleach should I keep on hand to add, to keep the level up? Any insight would be greatly appreciated.
Thanks again!
J

 

[mknauss]

The app says that because you are, but not to SLAM. SLAM is not a normal process. You use it when the pool water needs it.

You have a very large volume pool and you purchased weak liquid chlorine. So it will take alot of it to raise the FC to 20 ppm. And keep it there.

 

[Newdude]

SLAM FC is 40% of your CYA, so 20 FC.

Ch = 5/10+ (solid yellow

5 is FC, 10 is Br(omine). It's either/or, and you're testing FC.

Any advice on raising my TA?

80 is great. It will likely find where it wants to be when it's 60 to 100.

chlorine lock

They need to make up terms to explain what they don't understand. It's rubbish.

I wasn't there, but I'll tell you what went down anyway. They had you unknowingly jack your CYA level, with either tabs, powdered shock, or both. The more CYA you have, the more FC you need to sanitize at the same level and at some point you can't keep up with how high the FC needs to be. The pool goes green and the SLAM level needed is unattainable due to UV burnoff. So they throw their hands up and call it chlorone lock and you need to drain all that CYA that they had you add.

Your CYA is a 50 and we won't let you add anything that has CYA if you check with us first.

Any advice on slam

s-l-a-M(aintain). Slam loses efficiency any time below target FC. At first the FC may get spent in 2 or 3 hours and you need to top it off accordingly. As the slam progresses FC will hold longer and longer.

Brush and vac daily, at least once.

Monitor filter PSI and clean at 25 % increase.

As it clears, every hidden inch needs scrubbing. Inside the skimmers, ladder rails, auto fills, light niches, etc.

 

[PoolStored]

Thank you for your reply! Could you help me understand how much bleach I should add for my first SLAM. CYA 50 / FC 8.5 and bleach 7.5% The pool calculator says "your target is outside the recommended range" and at the bottom (5 gallons/1 quart and I'm confused. That seems like a lot of bleach to dump into the pool? How much more bleach should I keep on hand to add, to keep the level up? Any insight would be greatly appreciated.
Thanks again!

First, with the look of your pool, your SLAM should not be too hard. Link-->SLAM Process
Print the SLAM page out, read it three times, keep it in your back pocket. Paper copy is super helpful.

SLAM is a process, not a one time event. And, the first additions are always the largest ones because you are starting low. Once you get going the additions will be smaller as you keep a higher FC.

Based on YOUR CYA, we know that if you maintain 20ppm in the pool until you pass this test (Link-->Overnight Chlorine Loss Test), your CC<.5 and your water is clear, you have no algae. That level of FC maintains enough HOCl to kill bacteria and algae. It is safe for people and pool and equipment up to slam level.

You have a large pool, like me. It will take a fair amount of chlorine to clear your pool, but it will.

Ignore the error messages in PoolMath. They are there to make sure you know that you are using SLAM level, not normal targets...protecting you from accidentally having SLAM enabled when you don't want that.

Enter your current FC and Target (20)...use what it says.

As Marty indicated, 7.5% chlorine is pretty week. My pool was worse than yours and I went through about 40 gallons, but I was using mostly 6%. You can find 10% and 12.5%.

Hope that helps...

 

[Jamestown101]

Thank you I really appreciate the advice!

 

[wireform]

James,
Since nobody asked I will, how are you testing?

 

[Jamestown101]

Hello Everyone,
First, thank you for the advice so far!

Using my TF-100 I obtained the following results this morning:

ph 7.2
cl 5
br 10
fc 7
ch 250
ak 80
cya 50

Did my first slam (4.5 gallons @ 10%) right after and tested fc about 10hrs later and it was 30

The water appeared more yellow and a bit worse at the time of my second test. Is that normal? I used the bleach I found at Walmart (10%) but oddly, at least for a novice like me, yellow in color. Here's a picture of the container, codes and color. Does this seem right or has this bleach gone bad?

My fc jumped significantly between the two tests (7.5 - 30 while I was shooting for a slam target of 20) does that seem right, I expected it to fall?

Thank you!
J

 

[Jamestown101]

I should add that I throughly cleaned before the slam and brushed well during the slam