Help! Can't keep chlorine levels up!

randybenson81

New member
Jun 17, 2019
3
78130
Hi there. I'm in need of some help. I live in Central Texas and recently purchased a home with an above-ground vinyl pool It is about 12,000 gallons. I drained about 80% of the water a couple weeks back because the CYA was very high. Now, it's about a 30. I have been SLAMming the pool with liquid bleach to try to get everything kosher. Problem is, I can't maintain my Free Chlorine level. I have been testing and slamming twice a day the past week. Last night (9:45pm), after I added bleach, I was at a 13.0. This morning (9:00am), I was at a 7.5. My understanding is that it shouldn't really change overnight?

I have no idea what to do. The stairs haven't been in there for several days (so any possible algae in there isn't affecting it). The PH level is fine. I just took some water to PetSmart and they said I have "little to no ammonia" with their test strips. I don't know what else to try!

What do I do?? TIA
 

YippeeSkippy

Mod Squad
LifeTime Supporter
Jan 17, 2012
14,843
Evans, Georgia
Randy, welcome to TFP posting :)

Let me first know- do you have a proper test kit? Either the TF-100 or the K-2006C? You can't really do a SLAM process without one...y'know? Can you list all your levels for me-
FC
CC
pH
TA
CH
CYA

If you had FC of 13 last night, but 7.5 this morning (was that before or after the sun came up?) that means you still have something in the water chewing up your FC.

Continue on with your SLAM process as often as you can retest and re-dose. It goes faster then.

If you had ammonia you'd have NO FC and oodles of CCs. You're fine there.

Got any pics of the pool? Daily pics really do help monitor clearing, almost better than actually eye balling it.

Using plain, unscented, non-thickened, non-clorox brand liquid chlorine, right? Fresh stuff by manufacturers dates??

Maddie :flower:
 
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randybenson81

New member
Jun 17, 2019
3
78130
Thanks for the help. Yes, I have the TF-100 kit. And, yes, I buy the 10% pool liquid chlorine at Home Depot. I just SLAMmed it at about 9PM. It is now 10:30PM and the levels are:
FC - 13
CC - 0.5
pH - 8.2
TA - 240
CH - 300
CYA ~28

Seems like everything is good except for Alkalinity. Could that be causing the Chlorine problem? I need to bring pH way down to fix that?
 

LFrankow

LifeTime Supporter
Sep 27, 2012
608
Medicine Hat, Alberta
Your PH reading is unreliable when FC is over 10 ppm.
Algae is probably eating your FC, once you complete the SLAM process your FC will level out.
How much did your FC drop from 9 - 10:30?
TA you can fix after SLAM or I would.
 

randybenson81

New member
Jun 17, 2019
3
78130
I have been SLAMming for over a week. I have put about 13 gallons of bleach in over the past week. Should it really take this long? There is nothing visible in the pool. It looks pristine! I was at a 9.5 this morning (down from a 13 last night).
 

nhamp07

Bronze Supporter
Jul 24, 2018
128
New Braunfels, TX
Original poster is a good buddy of mine. I’ve been helping him along over the past week. I was at a loss so I suggested he make an account and post. The problem I have and not sure what to do with, is his pool is crystal clear but still losing considerable chlorine overnight.
 

Skenn81

Well-known member
Apr 23, 2018
145
Florida
Yippee.. about the light, side question relates to this thread. I took mine out during the slam and it has been sitting on the side deck now for a few days. What do I need to do to it before putting it back in? Would algae live up on the side of the pool when it is sitting there or would being in the Florida 93+ degree heat help sanitize it?
 

YippeeSkippy

Mod Squad
LifeTime Supporter
Jan 17, 2012
14,843
Evans, Georgia
Look in the niche where the light came out of.....that's a common hiding place for algae. Brush it good and get the chlorine in there.

As to the light itself, I guess just inspect it. I dunno if algae get in there?

Maddie :flower:
 

YippeeSkippy

Mod Squad
LifeTime Supporter
Jan 17, 2012
14,843
Evans, Georgia
If your pool doesn't get a lot of sun, your CYA can be lower. But that hot sun in Texas will burn the FC right out of the water if you don't have enough.

You just don't want *too much*