New to TFP (Kind of) Question about CH after Pool Refill (pool store didn't want to sale me anything!) and daily Chlorine loss

[Chemingway4]

I recently drained and filled my pool (3 weeks ago). The CH reading is 80ppm. I know that's low, but when I went to the pool store to get supplies, I was told not to worry about the CH as it would slowly rise over time. I thought it was odd that they didn't want to sale me anything, so I left. After doing a little more researching, I'm wondering if the slow rise in CH will be because it's taking it from the plaster! I didn't add anything on refill to bring the CH level to 80ppm; it's just from the tap. What should I do? Is a slow climb in CH okay? Should I just start using Cal-Hypo? I'm currently using 12.5% chlorine only for sanitation.

I don't know if this is related to the CH level, but the only issue I'm having with the pool is that I'm having to add almost a gallon of 12.5% chlorine every 24 hours to keep the FC in target range. I'm still playing with the numbers and trying to get it right. Like maybe I'm adding too much Chlorine and there isn't enough CYA to protect it and it's just burning off, or maybe I need to raise my CYA level and that'll help. I added 10lbs. of condition when I refilled the pool. The TFP calculated that that would bring my CYA to 46. When I checked it, I lost sight of the black dot between 40-50, so that matched with what I added. The pool is losing between 3 and 4.5ppm in 24hrs depending on initial CF level. I added more Chlorine the last 2 nights to keep the level above the minimum recommend. It worked, but it went from 9 to 4.5. Maybe that's just gonna be my pools normal, but my chlorine need is only gonna go up. We're not even swimming yet and I can't even imagine how much chlorine we'll need when we're on day 20 of straight 100+ degree weather! What's your advise?

Last night reading (after bringing Chlorine up from 4.5ppm) (losing between 3 and 4.5ppm in 24hrs depending on initial CF level)
FC-9

CC- 0

PH- 7.5

TA- 100

CH-80

CYA- 50
Pressure on filter is great.
Outside temps this week are in the mid 90s, pool is not shaded and south facing (9+ hours of sun daily), water temp 72-75 on evening checks)

 

[Mendy48]

Hello!

It’s normal to loss about 4ppm (give or take) of FC per day; especially when you live in a warm climate like that.

I’ll let someone else chime in here shortly about you CH level...

 

[mknauss]

A CH of 80 in Bakersfield is on the low side for fill water but possible depending on your district, etc.

You should add calcium to get your CH to ~250 ppm. You can use Cal Hypo, but realize it will take awhile. Up to you if you wish to risk it.

If you are consuming more than 4 ppm FC right now I would suggest doing a Overnight Chlorine Loss Test to check for organics. Outdoor temperature does not effect FC consumption that much. Sun angle does. Right now your sun angle is similar to what you have in August.

How does the water look?

 

[Chemingway4]

A CH of 80 in Bakersfield is on the low side for fill water but possible depending on your district, etc.

You should add calcium to get your CH to ~250 ppm. You can use Cal Hypo, but realize it will take awhile. Up to you if you wish to risk it.

If you are consuming more than 4 ppm FC right now I would suggest doing a Overnight Chlorine Loss Test to check for organics. Outdoor temperature does not effect FC consumption that much. Sun angle does. Right now your sun angle is similar to what you have in August.

How does the water look?

Right now the water is crystal clear. Never looked so good, actually. The over night test was next on my list. I've just been checking when the sun goes down, adding Chlorine to bring it back up and retesting after 30 minutes with the pump running. I'll do the overnight tonight and post my results. Thank you. If I decide to use Cal hypo to slowly raise the CH, is there anything else I should lookout for? Like PH or TA? I like using liquid, but cal-hypo seems a little easier

 

[Chemingway4]

A CH of 80 in Bakersfield is on the low side for fill water but possible depending on your district, etc.

You should add calcium to get your CH to ~250 ppm. You can use Cal Hypo, but realize it will take awhile. Up to you if you wish to risk it.

If you are consuming more than 4 ppm FC right now I would suggest doing a Overnight Chlorine Loss Test to check for organics. Outdoor temperature does not effect FC consumption that much. Sun angle does. Right now your sun angle is similar to what you have in August.

How does the water look?

Also, any thoughts on my CYA level? Is there a benefit in raising it? My gut says no.

 

[mknauss]

When your pH reaches 8 lower it to 7.6 with muriatic acid. The TA will fall over time.

If you use Cal Hypo, be sure it full dissolves and does not sit on the bottom of the pool. Brush it around if necessary.

 

[mknauss]

Also, any thoughts on my CYA level? Is there a benefit in raising it? My gut says no.

For a non-SWCG pool, a 50 ppm CYA is appropriate. Be sure to test it every month during swim season. It will degrade very slowly with elevated water temperatures. Use trichlor pucks in a floater or CYA granules when you need to bump it back up by 10 ppm or so.

 

[Chemingway4]

When your pH reaches 8 lower it to 7.6 with muriatic acid. The TA will fall over time.

If you use Cal Hypo, be sure it full dissolves and does not sit on the bottom of the pool. Brush it around if necessary.

Thank you for your help. I will do the over night test and post results.

 

[scdaren]

In the CA central valley (at least in Fresno and I'm guessing probably Bakersfield, too), the CH of the fill water, and thus the speed at which CH rises on its own, varies depending on the water source they are using. In wet years there is surface water available, and that will be low CH. In dry years (or often in the winter months) when snow-melt surface water is not available and they are pumping groundwater instead, the CH of the fill will be a lot higher. I have so far seen fill water ranging from 25 to 100 depending on the source.

This being a fairly wet year, definitely don't wait around for evaporation to raise the CH on its own -- add the calcium to get it up to recommended levels.

 

[Chemingway4]

In the CA central valley (at least in Fresno and I'm guessing probably Bakersfield, too), the CH of the fill water, and thus the speed at which CH rises on its own, varies depending on the water source they are using. In wet years there is surface water available, and that will be low CH. In dry years (or often in the winter months) when snow-melt surface water is not available and they are pumping groundwater instead, the CH of the fill will be a lot higher. I have so far seen fill water ranging from 25 to 100 depending on the source.

This being a fairly wet year, definitely don't wait around for evaporation to raise the CH on its own -- add the calcium to get it up to recommended levels.

Thank you so much for the added info! I didn't know that about surface water vs ground.

 

[Chemingway4]

Right now the water is crystal clear. Never looked so good, actually. The over night test was next on my list. I've just been checking when the sun goes down, adding Chlorine to bring it back up and retesting after 30 minutes with the pump running. I'll do the overnight tonight and post my results. Thank you. If I decide to use Cal hypo to slowly raise the CH, is there anything else I should lookout for? Like PH or TA? I like using liquid, but cal-hypo seems a little easier

I did the overnight test like you recommended. I checked the chlorine level at 9:30pm and it was at 4.5ppm. It was at 9.5 the night before so it lost 5 ppm in a 24 hour period. I brought the level up to 9.5ppm at 10pm. At 6am this morning it had had only dropped to 9ppm. So that's good. Should I be concerned about the 5 point drop or is this just my pools normal?

 

[mknauss]

I brought the level up to 9.5ppm at 10pm.

You tested that level of FC last night after running the pumps for 30 minutes after adding liquid chlorine?

 

[Chemingway4]

You tested that level of FC last night after running the pumps for 30 minutes after adding liquid chlorine?

Yes. The pump ran for about 45 minutes

 

[mknauss]

Great! There is a good chance your normal FC loss is 4 ppm. You have a lot of dust from agricultural activities in Bakersfield. That can raise our FC consumption.

Keep adding liquid chlorine and testing!

 

[Chemingway4]

Great! There is a good chance your normal FC loss is 4 ppm. You have a lot of dust from agricultural activities in Bakersfield. That can raise our FC consumption.

Keep adding liquid chlorine and testing!

Thank you! I'll keep at it.