Houston Texas area pool chemistry question

Lis010

Active member
Feb 26, 2018
35
0
Houston, TX
#1
Hi all!!!
I am definitely a newbie at this pool care. Can you experts please help guide me with some advice???
My water chemistry values are as follows:
FC: 5
TA: 90
CH: 230
CYA: 48
pH: 7.5
They’ve been like that for a couple weeks now, that is until we had a pool party a couple of days ago.
Now my chlorine values keep dropping so quickly. Is it because of the rising heat, and pollen or is it because my CYA needs to be higher??? I try not to overshoot on the CYA because I don’t want to have too much of that...
1. what should my target values be???
2. Is it routine that I should shock the pool after having many people in it???
3. At what FC level and after how long a period with low FC should I shock the pool??? It was at 3ppm last night, this morning it was between .5-1ppm.
Any good recommendations appreciated!!!
Thanks.
 

Jimrahbe

Mod Squad
LifeTime Supporter
TFP Expert
Jul 7, 2014
10,162
1
Bedford, TX
#2
Lis,

Most pools use between 2 to 4 ppm per day, just sitting in the sun... Add in a pool party and an "accident" or two and your chlorine can get consumed pretty quickly..

I suggest you increase your FC to 10 for a couple of days... What is your CC level?

How are you testing and how are you chlorinating your pool?

Thanks for posting,

Jim R.
 

Lis010

Active member
Feb 26, 2018
35
0
Houston, TX
#3
My CC is less than the indicator would read using the Taylor 2006 complete test; so, the lowest 1 drop is not showing a reading. Up until a couple of days ago, my FC would stay at 2-5 ppm after adding whatever amount of 10% bleach (NaClO) that is indicated to keep at 5ppm; averages about a weekly addition of 1 gallon.
 

domct203

LifeTime Supporter
TFP Guide
Bronze Supporter
Jun 4, 2015
3,959
0
CT
#4
Hi all!!!
I am definitely a newbie at this pool care. Can you experts please help guide me with some advice???
My water chemistry values are as follows:
FC: 5
TA: 90
CH: 230
CYA: 48
pH: 7.5
They’ve been like that for a couple weeks now, that is until we had a pool party a couple of days ago.
Now my chlorine values keep dropping so quickly. Is it because of the rising heat, and pollen or is it because my CYA needs to be higher??? I try not to overshoot on the CYA because I don’t want to have too much of that...
1. what should my target values be???
2. Is it routine that I should shock the pool after having many people in it???
3. At what FC level and after how long a period with low FC should I shock the pool??? It was at 3ppm last night, this morning it was between .5-1ppm.
Any good recommendations appreciated!!!
Thanks.
Have you picked up one of the recommended FAS DPD test kits, or are you still using the Leslie's DPD test kit that you mentioned in this thread?
https://www.troublefreepool.com/thr...ool-start-up-any-helpful-insights-appreciated

We do not recommend random pool 'shocking', if your chlorine level has fallen below recommended levels (with your CYA of 50ppm, your FC should never fall below 4ppm) you are giving algae a chance to start growing. If your FC was at 3ppm last night (after sundown), and was 1ppm this morning (before the sun was on the pool), you have something (most likely algae) in the water that is being oxidized by the chlorine. At this point I would recommend at least an [OCLT][/OCLT] to determine if a may be needed. If you still do not have a FAS DPD test kit you cannot properly perform a SLAM, or an OCLT.

Please add your test kit info to your signature.

You can try elevated FC levels for a couple of days as mentioned, but without a FAS DPD test you will not be able to perform the OCLT to see if the water is sanitary.

Thanks for posting.

- - - Updated - - -

My CC is less than the indicator would read using the Taylor 2006 complete test; so, the lowest 1 drop is not showing a reading. Up until a couple of days ago, my FC would stay at 2-5 ppm after adding whatever amount of 10% bleach (NaClO) that is indicated to keep at 5ppm; averages about a weekly addition of 1 gallon.
OK, you have a recommended kit, that's good.

Are you saying that after adding the 5 drops of R-0003, the sample remains clear?

I would do an OCLT tonight.
 

Texas Splash

Mod Squad
LifeTime Supporter
TFP Expert
#6
Now my chlorine values keep dropping so quickly. Is it because of the rising heat, and pollen or is it because my CYA needs to be higher???
Hi Lis! :wave: Looks like your recent party placed a little bit of extra stress on your water and is in need of some extra help. Parties can do that. :party: Jim & Dom gave you some good advise, so for today simply definitely punch that FC up to about 10 with some good-old regular bleach from Walmart or HEB and try to let it stay there throughout most of the day and thru this evening if you can. Check it again tomorrow, and if you experience a big FC drop again (more than 4ppm), then you should do an overnight (OCLT) test to see if you need to perform a SLAM (link below).

We typically round-up CYAs, so yours would be 50 which places your ideal FC range between 6-8 on the Chlorine/CYA Chart (link below). Since your FC did drop very low this morning, the additional FC today should help. For parties, we might increase FC an hour or so before the event by about 2 ppm just to account for the additional swimmer's load, oils, lotions, hair sprays, spilled drinks, etc. :wink: Then check again immediately afterwards if possible in case there was a large drop in FC.

Your CYA should be in a good place at about 50 this time of year. You probably should add the K-2006 to your signature as well so you don't asked all the time. :blah: So for now, increase the FC and watch it for about 24 hrs to see if you dodged a SLAM bullet, or if you need to do one. Even if you do have to SLAM, your water should respond fairly quickly to pass all 3 SLAM criteria. Hope that helps.
 

Lis010

Active member
Feb 26, 2018
35
0
Houston, TX
#8
Thank you all for your advice!!!
My next question needing clarification is, I read that ideal FC should be 2-5ppm and not to exceed 5ppm to prevent Cl related physical irritation/problems. Wouldn’t the FC between 6-8 for the correlating CYA at 50 become a problem to people swimming in the pool??? I’m trying to understand the mechanics behind it.
Also, as per a previous comment, does CYA concentration need to change in the different seasons??? :confused:
 

Texas Splash

Mod Squad
LifeTime Supporter
TFP Expert
#9
Lis, as long as your CYA and FC are balanced together as noted on that Chlorine/CYA Chart (link below in my sig), the water is safe to use. The statement you might hear about low FC levels is an antiquated pool standard that never took into consideration the correlating impact of an elevated CYA. So naturally, as the CYA (stabilizer) level increases, so must the FC level. The pool industry is just now starting to make some changes, but many still use that generic reference and it's wrong. Stick with the chart and you'll be fine. It's perfectly safe/

As for changing your CYA throughout the year ... you can. Typically in our areas, we like to keep CYA a little bit higher in the summer to protect the FC from the sun and help it last longer. My pool gets full sun all day, so from May - Sep I keep my CYA at a minimum of 50, and sometimes will bump it higher to 60-70. Of course when I do that, I refer to that chart to ensure my FC is balanced to that new number. So you need to do that as well. In the winter, I can let my CYA naturally begin to fall as low as 30-40 if I want to because there is not as much (sun & heat) stress on the water.

Hope that makes sense to you now. The more you read here and refer to those charts and products we show you, the more it will stick and become second-nature.