New Owner of a 2nd hand spa - chlorine use seems high

[mcmoyer]

Hey All, long time pool owner who uses mainly liquid chlorine and pucks only when I need to get my CA levels back up. I recently acquired a 2nd hand spa. It's Master Spa Legend Series, 410 gallon. The previous owner had been using bromine. When I read the manual, Master Spa seems to prefer chlorine. So I just went with chlorine. I can put in a tablespoon of Dichlor one day and then next day it's reading almost no chlorine via the DPD-FAS test. This is with, or without, someone using it. I ordered some Ahh-some and performed the cleaning twice. First time, lots of gunk came out, next time, almost nothing. Filters look fine. Is this a normal amount of chlorine usage? All the online guides I see say, "test at least once a week to see how much chlorine you need to add". Heck, if I waited a week, I'd hate to see what it looked like.

Any suggestions on what I might check next? My ph, ta, cal all seem to be fine.

 

[mas985]

What is the CYA level and is the spa in the sun?

What is the FC level after adding the Dichlor (and dissolving)?

 

[mcmoyer]

What is the CYA level and is the spa in the sun?

What is the FC level after adding the Dichlor (and dissolving)?

I just refilled this about a week ago and haven't tested the CYA which I figure should be minimal based on only using a tablespoon of Dichlor each day. The spa cover remains on it throughout the day so the water is not in the sun.

I measured the FC after 1 tablespoon and it was 3ppm.

Then of course I got impatient and superchlorinated with 1 oz of Dichlor. Will measure again in a half hour.

 

[mcmoyer]

I got to reading more about chlorine levels and temps and think maybe me keeping mine at 102F 24x7 has a lot to do with my chlorine usage?

 

[Mdragger88]

Is your dichlor 99%? As PoolMath assumes this but i have seen some that is not. When I put it in it shows it should raise u to 5 ppm.

Stop using dichlor & switch to liquid chlorine when your calculated cya hits 30 ppm.
You can follow this guide

How do I use Chlorine in my Spa (or pool)?

If you have a question about any information within this Sticky, please start a new thread for yourself where you will receive very quick responses to your specific questions. Thank you! Introduction There are two main things to consider when maintaining your hot tub water, Water Balance and...

www.troublefreepool.com

It is also a sticky @ the top of this forum.
The temp does play a part in fc consumption which is why most raise to 10 or so after using to get them through to the next dose. Enough to make up for current bather load & normal fc consumption. 3 ppm doesn’t last days. Does this spa have a uv system? That can impact your fc as well.
If u find it inconvenient to maintain daily dosing a drop in swg can do the heavy lifting for u . It will still require u to dose w/ liquid chlorine for heavy bather loads & occasionally dichlor to replenish cya.

 

[mas985]

I got to reading more about chlorine levels and temps and think maybe me keeping mine at 102F 24x7 has a lot to do with my chlorine usage?

Absolutely. It has a very large impact on chlorine consumption. It means your target may need to be higher to last through dosing's.

 

[mcmoyer]

To follow up: my CYA level is almost non-existent. My tube goes to 20, and while it was a bit cloudy, I could still see the dot.

This is my first time using chlorine in a hot tub. I had an in ground propane heated standalone hot tub before that was using bromine. Since I only heated it when I needed it, it was fairly hands off aside from checking the floater every once in a while. With this spa, the manual says it can heat 5-6 degrees each hour so that's why I tend to keep it at temp since I use it almost every night. I'm guessing that my chlorine usage isn't too far off the norm.

I've got all the stuff from the previous owner to run a bromine system. I might try it for a bit until the next flush and fill. Seems like it's supposed to be a bit more stable at higher temps.

 

[mcmoyer]

Just checked my FC levels. At 12pm I added 1 tablespoon. That brought it up to 6 ppm. I measured at 9pm and it was at 4 ppm. That seems inline with what you guys have said, at least about bumping it to 10 ppm to get through the next day.