Going out of town and struggling to increase/maintain free chlorine

[digimack]

Hi all! I wanted some feedback on what I should do. Here's the situation:

We are about to leave town (Houston TX) for 10 days and I'm worried about coming back to a green pool.

I'm struggling to keep FC above 0.5 (measured with my TF-PRO kit). We can see small patches of algae scattered throughout the pool that are easily brushed off the bottom and walls.

We use chlorine tabs and I'm afraid they've raised CYA too much over the past month. In addition to the tabs, I added a gallon of 10% liquid chlorine over the span of two nights and it didn't budge the FC. I'm guessing it burned off from the time it was added to testing the next day.

Water is clear and most measurements are in line. CYA is probably higher than it should be, but I'm not the best at measuring it with the black dot, etc.. We cleaned the filter this past weekend, it was dirty but not alarmingly so. Last cleaning was Nov 16.

Water Temp: 91°C
FC: 0.5 | CC: 0.5 | TC: 1.0
pH: 7.6 | TA: 80 | CH: 275
CYA: 60-80 (depends on who is reading it)

My strategy is to immediately add more 10% liquid chlorine over the course of the next 48 hours (which is when I leave town). I have 3 gallons ready to deploy. I'm hoping this will get FC higher and then it will burn off to normal and the tabs would do the rest. I likely won't have time to SLAM or drain the pool to lower CYA.

Any other ideas on what I can do. I don't have anyone that I trust to monitor the pool when I'm gone and I prefer not to use a pool company.

Thanks for your feedback!

Brian

 

[duraleigh]

That'll be tough. 10 days in the houston summer is gonna' take a lot of chlorine. I would try this.......bring the FC up on the day you leave all the way to SLAM value and maybe just a SMALL amount more......probably around 30 or so then add maybe 4-6 tabs or so and cross your fingers.

Your chlorine might hold out until you get back. Your CYA might bee too high but you can knock it back down with a partial (maybe 1 foot) drain/refill.

Is your pump on a timer?

 

[Dirk]

Aren't y'all in a heat wave right now down there? You've already got algae (you say) and you're having trouble getting FC to hold even when monitored and adjusted daily. And you've got some CC to boot. That sounds to me like you've already got a "green pool." Your algae outbreak is in mid-stride, it's just not full blown yet.

So not only is your CYA and the weather creating havoc with your FC, you've got algae chewing away at it, too.

I just don't see how you can expect anything but a green pool on your return, no matter how much chlorine you add today or tomorrow. Just sayin'.

I also don't see a pool service that comes once a week doing much either. Having some random company show up once or twice while you're gone, to throw in a gallon or two of chlorine would be better than nothing, I suppose.

You need to exchange some water and SLAM your pool, of course, you already know that. And can't. So the next best thing would be to engage someone to add chlorine to your pool every day while you're gone. We'd have to do a little pool math to give you an amount per day, to figure out how much chlorine you'd need to stock. But it's going to be a heck of a lot more than three gallons. That might keep the impending outbreak at bay until you can get back and solve this correctly.

Or just give @duraleigh's MO a go, and deal with the CYA and any green when you get back. Whatever happens while you're gone will be fixable.

 

[digimack]

Thanks, @duraleigh! Yes, the pump runs on a daily schedule from 7a - 7p at 2500rpm (3600 gal per hour). Something I just noticed is the Rainbow 320 chlorinator is set at 3. My hand written logs show I intended it to be at a 1.5-2 range. That may be the reason my CYA has gotten out of hand. I'm not sure how long it's been at 3, but that might explain why I was burning through chlorine tabs faster than what I was expecting.

Should probably bump it back down to 1.5 or 2 setting, although I don't know if that is smart right before leaving town.

I think I can probably drop the pool a foot starting this evening and refill overnight, then add more liquid chlorine in the morning, test again and head out of town after lunch.

Thanks, @Dirk! I like both approaches and I think its logical to stock up on several gallons of chlorine. I have a neighbor that is building a pool now, so maybe I can persuade him to stop by on the daily.

 

[duraleigh]

I would keep your same level of CYA 'til you get back. Diluting it now only depletes your FC and CYA both.

leave your pool water where it is and then deal with it according to it's condition upon your return.

 

[Dirk]

Thanks, @Dirk! I like both approaches and I think its logical to stock up on several gallons of chlorine. I have a neighbor that is building a pool now, so maybe I can persuade him to stop by on the daily.

If that's a possibility, then you could do this. Calculate the necessary daily chlorine amount to maintain the proper FC. You can err on the high side. Then prepare those doses for him. If it's a gallon a day, that's easy. If less, then use old plastic jugs or coke bottles, whatever. Then label and/or separate them into 10 "chunks." Then just ask him to dump in one chunk per day. That way, it's really not that much of an ask. He doesn't have to test or calculate anything. Just show up and dump. I would certainly do that for a neighbor.

Set your pump to run during the day, or whatever time slot you feel would cover his visits.

You can still goose the FC to SLAM level before you go. The neighbor's additions will just maintain the SLAM level, or at least keep if from sliding too far back down.

FYI, your theory about the tabs has some truth to it, but the bottom line is: maintaining a properly sanitized pool with tabs is not sustainable. The settings won't matter. Eventually you'll end up with too much CYA, which will then make maintaining FC untenable, which always results in a water exchange. That is just how tab-pools must be maintained. It was just bad luck that the end of your cycle coincided with your time away.

If you want to rid yourself of this endless cycle, use a saltwater chlorine generator. That's what most of us here do. I can leave my pool for up to two weeks at a time (maybe more) and the FC will be steady the whole time and my pool will be pristine upon my return.

We used to say the cost of using an SWG, over time, equates to that of using liquid chlorine or tabs for that same amount of time. But we were discussing the math the other day and it seems SWG is much better now. So not only will an SWG probably save you money over the long haul, you never have to lug chlorine or tabs ever again! No storage, either. And no worrying about freshness or expiration dates. An SWG makes just the right amount of chlorine your pool needs, fresh, each day.

 

[Newdude]

I have a neighbor that is building a pool now, so maybe I can persuade him to stop by on the daily.

GENIUS !!!!! FaceTime him every evening and walk him through the FC test. You get the free help and he'll be a pro before his pool is ever filled. It's truly a win-win.