Using a lot of bleach!

[ksepurvis]

Using TFP test kit:

CYA holding steady at 50.
TA holding steady at 70.
PH holding steady at 7.5. (Only when I started with TFP have I EVER had and kept such a balance!)
At night, FC testing at 5ppm.

I lose 1 ppm overnight; 4 ppm during day.
So, based on pool calculator, using 12.5% bleach (Vertex) to bump overnight to 10 ppm - I am adding 8.5+ cups of bleach per night! This seems like an extraordinary amount of bleach, particularly at 12.5% chlorine! Is it because our temps are so high? Getting 8-10 hours of sunlight on pool? Is the Vertex the problem? I do get it a my local pool store - with discount, it runs cheaper than bleach.

My husband is questioning the cost effectiveness of this method vs. tablets, even though I remind him about having to dump so much water due to increased CYA with tablets. I honestly don't remember how much those tablets cost though, but I do know I don't like having to drain so much water out of the pool when CYA gets high!

Thoughts on the amount of bleach I am using???

 

[Texas Splash]

Heat (water temp), direct exposure/angle to the sun, and organic materials all contribute to FC consumption. Whenever you have a concern about losing more than 4 ppm FC per day, that's an ideal time to consider doing an overnight (OCLT) test. If you pass the OCLT and lose no more than 1 FC overnight, then you can feel assured you are basically algae-free and the FC loss is mostly attributable to the sun. The next logical step then might be to increase CYA slightly - maybe by 10 ppm. At the same time, remember the FC target increases too. We ideally try to keep FC consumption between 2-4 ppm in the summer.

But always ensure algae is ruled-out first before increasing FC. Make sense?

 

[ksepurvis]

I will do the OCLT. I am not sure I understand increasing the CYA - that will increase the amount of chlorine to add. Is it a stabilization issue? I hate to increase CYA after all I've done to DECREASE it to an acceptable level!

 

[Swampwoman]

So you're raising it to almost 10 ppm FC each night?
8 cups of 12% in a 13,000 gal pool would be adding 4.8 ppm

If your cya is 50, your target range is 4-6 ppm.
If you pass the OCLT, try dosing lower, eg to 7ish, and see where it is the next night. Sometimes "over dosing" is just wasting chlorine since its a percentage that burns off.

In general, 4+ ppm seems a wee bit high in terms of daily consumption, but every pool is different.

 

[Andrew Howard]

I've been using one 128 once bottles of 12.5 % every four days. Temps 86 in pool and good amount of sun

 

[smooth2222]

Also if your swimming and using the pool a lot, you will burn more chlorine.

15,000 gallon, 12.5% bottle last me 3 days, we swim a lot too. Michigan here

Put in 1/3 bottle every night

 

[MarianParoo]

Just for gags, price out the tabs/pucks. I guarantee you will be ahead of the game even without the cost of draining for high CYA.

 

[ksepurvis]

I have conducted the OCLT and have less than 1 ppm variance. So I think I am algae clear. (Yippee)

Question: You say we try to keep FC consumption between 2-4 ppm in the summer. For me, with CYA at 50, I am thinking that would be about 5 ppm minimum. Considering FC loss occurs during the day, don't you have to get the chlorine high enough at night to allow for loss during the next day - high enough so that FC loss does not go below your minimum?

How can you KEEP (consistent throughout the day) FC consumption at 2-4 and account for daytime loss? Are you checking FC periodically during the day and adding chlorine as needed all day long?

What am I missing here?

 

[ksepurvis]

Swampwoman - Thanks. FC was indeed high yesterday morning. So this morning I am at 7 ppm (<1 ppm FC loss overnight). I am going to check it tonight, and see how much FC loss I get today, although it will be cloudy/rainy today. I am going to try adding less than suggested and see if I can put in less if the excess is just burning off.

My pool does get 8-10 hours direct sun daily and it has been higher temps than normal for us in June. Water temps already at 82-86!!! Hope it isn't 100 by August!!!!

 

[Swampwoman]

The [fc/cya][/FC/cya] chart puts you at min. 4, target 6.
If you dose to 8, you will be using 20% less chlorine each day compared to dosing to 10. Try dosing to 8 to see if by the next night you still have 4. If so, you will be saving 20% of your chlorine cost.

 

[Mr Bruce]

5ppm loss per day is a bit high, especially for CYA 50. 2-3 ppm loss per day is more reasonable. With your pool size, you are looking at adding about 1/2 gallon of 8.25% every other day. That should keep you ahead of going below minimum.