High chlorine usage?

[ekapigian]

First time poster, although I've been lurking around the forum for a month or so. I've been using the TFP method and trying to dial in my daily chlorine usage on our new pool (only 3 weeks old). Taking readings daily and experiencing a consistent 50% or so loss of chlorine per day. I bring it up to about 7.5ppm and it falls to 3.5-4ppm by the next day. Does this seem normal? Do I need to keep increasing my CYA above 50? I live in an area where temps are high--100+ during June and pool is exposed to full sunlight for a majority of the day (10+ hours). Seems like I'm using a lot of bleach daily to bring it back up to a point where it won't fall too far below the minimum, and I've been using 3 trichlor pucks in a feeder to bring CYA levels up to 50. My current readings are as follows:

CH - 225
TA - 120
PH - 7.5
CYA - 40-45
CC - 0
FC - 3.5 (before adding bleach for the day)

 

[Patrick_B]

Welcome to TFP!

That isn't too unusual. We have several members in full sun losing 4 PPM daily in full Sun with warm water. It won't hurt bumping the Cya a little higher to see how that helps. I'd shoot for what I thought looks closest to 50-55 at most, and see how it goes at that level. If all else is well in the pool, I wouldn't worry much, just see how that goes, and enjoy the summer.

 

[Richard320]

If the pool gets a lot of use by children or heavily sunscreened adults, your chlorine consumption is normal.

You should check http://www.hasapool.com/dealer_locator_hasa.php to see if someone nearby sells the returnable jugs of 12.5% chlorine and crunch some numbers.

 

[ekapigian]

Thanks for the replies. It is new so there have been a lot of people over on the weekends, including children, but weekday use is pretty moderate. Sunscreen is a must with these temps, of course. I followed the link and it looks like there is a HASA dealer just a few blocks from me. I'll have to see if they have the returnable jugs. Currently, I've been using the Kem-Tek liquid chlorine because it is so cheap at our local Lowes--less than $6 for 2 gallons.

 

[tim5055]

You say inground pool, vinyl or gunite?

Another thing you may try is bumping the CYA up just a tad. Mine is in full sun all day and I try to keep it around 50-60. If you increase the CYA remember to up your target FC.

 

[ekapigian]

You say inground pool, vinyl or gunite?

Another thing you may try is bumping the CYA up just a tad. Mine is in full sun all day and I try to keep it around 50-60. If you increase the CYA remember to up your target FC.

Thanks for the advice. It is gunite with a Luna Quartz plaster (or whatever material it is considered). I should probably add that to my signature for clarification.

 

[pooldv]

Yes, Luna Quartz is considered to be a plaster pool. Adding to your sig would be helpful in the future.

 

[jmastron]

You're in a similar climate to me (a bit hotter down there), and our pool is at the same CYA level -- we too are losing at least 3-4ppm/day . I did a short SLAM last week because I'd let the FC drop below the target a couple times not realizing the loss rate was that high, and because the cover was on for about a week straight -- it reduces evaporation and FC loss, but with the very warm water below and no sun on the water itself can cause its own issues. I take it off at least every other day now whether anyone's using the pool or not so it can "breathe". But in the end, I think that's just a normal FC usage rate for a CYA of 40, full sun, and high 80s water temps.

Last summer when we bought the house the CYA was 80 before some winter draining -- it definitely used less chlorine (once brought to the right target), with the downside of needing much more to SLAM, and having to deal with people who think "wow, that's way too high!", like the Leslie's that refused to finish testing the water because FC was 7 ppm. That was the last store test I went in for; I now trust my TF-100 numbers exclusively.

BTW, if you're not testing the water again 30 min after adding chlorine to know you're really getting to 7.5, some here have opined that the HD/Lowes chlorine isn't their first choice because it turns over slowly and sits outside in many stores so may not be full strength. The HASA chlorine at the store I go to now comes in regularly and seems to be true 12.5%. BTW, this store wasn't on the HASA site, so I didn't know to go there until they sent a 3-for-4 coupon.

 

[ekapigian]

Thanks for the advice. I have heard that about the Lowes liquid chlorine. I'm currently testing twice a day in the evenings. Once before adding chlorine and again about an hour after. My experience with Lowes chlorine has been about the same as others on this forum. Some jugs are accurate according to the pool calculator and others I need to add a little bit extra because it is no longer at full strength. Probably all the more reason to switch to HASA chlorine that is true 12.5%.

I am surprised that Leslies refused to finish testing because your FC was 7ppm. Wouldn't that be about normal shock level for a pool even if you weren't following the TFP method?

 

[BuckeyeChris]

adding cya with pucks is tricky because you have to wait until they totally dissolve, then wait a week, then test cya, then add more pucks if necessary. Because the CYA takes a week to show up. During that time your FC levels are all over the place because the pucks are giving you some FC along with your bleach. But, how much FC is dependent on your water flow.