Drain and Refill - Advice?

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If you had some trichlor tablets, you could raise your FC & CYA and lower your pH and TA in one fell swoop ;-)

Get that CYA up to 50ppm and you'll see the FC survive a bit longer.


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Okay so I tested last night and here are some updated numbers. I actually had some chlorine left this time and the liquid stabilizer brought up the CYA as predicted.

FC=1
CC=0.5
pH=7.6
TA=140 (more accurate than last test)
CH=212
CYA=40
CSI=0.14

I added a bit more acid to bring the pH down to 7.5, added my chlorine and will re-test tonight. Hopefully whatever was eating it up is killed by now unless it was just the low CYA or both. I still want to get the CYA up to 50 but should I wait a few more days and test again to make sure it hasn't gone up past 40 or should I go ahead and add more now? Also, I would like the CSI to be a bit lower so maybe I'll add more acid and aerate to lower my TA unless you think I should use TriChlor instead. I suppose that would bump up my CH a bit and I do have ONE 3" tab left from
 
Based on those latest test results, watching/increasing your FC would be my #1 focus right now. It should never get that low. Your FC will get used-up by two things - algae and/or sunlight. So watch the FC consumption during the day. If it exceeds about 4ppm in one day, you may want to do an OCLT to rule-out organics. Yes, CH could go-up just a little bit to about 250. CH is sold under a variety of names, including Hardness Plus, Balance Pak 300, Calcium Hardness Increaser, etc. Hope that helps.
 
Just a quick update. When I got home yesterday, FC was at 1.5 and CC was 0.5. I added as much chlorine as the calculator told me to get to 5ppm and waited for the sun to go down. Checked after dark and FC=3.5, CC=0.5. Checked this morning and FC=3.5, CC=0.5. CYA was still at 40 so I may go head and add more now to get to 50. I'll check again when I get home today and hopefully the sun eats less than 2ppm of what's in there now. I wonder if my pool is larger than 15,000 gallons and that's causing some miscalculations. I really don't know how big it is since I didn't build it and 15,000 is an estimate based on my monthly water consumption compared to last year when I drained/refilled the pool.
 
The calculator is a good tool to assist with modifying your pool volume. Keep some good notes on what you add, and over time you should get pretty close. As for the drops in FC, just do your best to stay at or above your target of 5 ppm. Below that and it gets dicey. If you are still suspicious about FC loss, the OCLT will confirm. If you have any questions about how to perform the OCLT, just let us know. Have a good day.
 
2ppm to 3ppm loss is not at all unreasonable to expect during the day even for clean water. You need to target a morning FC addition such that your FC never drops below 3ppm. Probably something closer to 5ppm.

Also, your overnight chlorine loss (or lack thereof) is encouraging but the numbers are so low and the measurement too course (0.5ppm/drop) to make it meaningful. There was a thread in The Deep End that discussed the proper way to do an OCLT and the consensus, I think, was that it would be best to raise your FC up to 10ppm and then measure your overnight loss (with pumps running and SWGs turned off).

That being said, I really think you need to raise your FC a bit more in general.


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AB, Matt is absolutely correct on the OCLT issue. So just incase you do end-up trying another one soon, here are a couple good pieces of info to have handy to review:
When performing the OLCT, remember that it must be done when the sun has dropped – no sunlight on the pool. About 8 hours total is recommended. Also, your FC level should be elevated more than normal. Starting (bedtime) FC could be close to your SLAM level, but no lower than 10. Anything less and you may not receive an accurate portrayal of FC loss (by percentage), even if it’s only 1 ppm.
Click to expand...

Pool School - Perform the Overnight FC Loss Test (OCLT)
 
Oh I missed that thread. I may redo the OCLT tonight then, as I was just following the page found in Pool School. Also, my pump wasn't running overnight as maybe it should have been. I thought about adding more chlorine this morning but the pump runs in the evening on it's current schedule. I may have to add in some run time early in the day to compensate. I was happy to see no loss overnight though, really didn't want to have to SLAM this weekend. Hopefully once I get my CYA up a little it will be fine.
 
Ale_Brewer said:
Oh I missed that thread. I may redo the OCLT tonight then, as I was just following the page found in Pool School. Also, my pump wasn't running overnight as maybe it should have been. I thought about adding more chlorine this morning but the pump runs in the evening on it's current schedule. I may have to add in some run time early in the day to compensate. I was happy to see no loss overnight though, really didn't want to have to SLAM this weekend. Hopefully once I get my CYA up a little it will be fine.
Click to expand...

Is you current plan to manually chlorinate?

If so, then you should add an early morning pump run time to your schedule. It is better to chlorinate in the morning so that your pool water is doses correctly throughout the day. Most people that manually chlorinate add bleach in the AM and test in the evenings. All you need is 45mins to an hour for good mixing.


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JoyfulNoise said:
Is you current plan to manually chlorinate?

If so, then you should add an early morning pump run time to your schedule. It is better to chlorinate in the morning so that your pool water is doses correctly throughout the day. Most people that manually chlorinate add bleach in the AM and test in the evenings. All you need is 45mins to an hour for good mixing.


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Click to expand...

So I've been doing this method for a week now. I have been having to add (what seems to me) lots of chlorine each day. Dosing in the morning with the pump running for an hour to mix, then pump runs from 5pm-10pm. Testing around 9pm, my levels have been anywhere between 2-3.5 FC. I started testing in the morning too before dosing to make sure I'm not losing chlorine overnight and I'm not. Also, CC is always at or below 0.5. I've bumped up my CYA to 50 so my target FC is now 6. I've been having to add anywhere from 64-77 oz. of 12.5% each day. Does this sound like a normal amount for TFP? My pool does get FULL sun until about an hour before sunset. Is the sun just eating it up that fast? Do these numbers sound normal?
 
So it looks like you're adding enough bleach to get to 8ppm FC in the morning and you're losing about 4.5-5ppm over the course of the day. Your overnight loss is minimal and your CC's are normal (0-0.5ppm is totally normal). For 50ppm CYA, your target FC level should be 6ppm and you should not go below 4ppm.

I would say your FC loss is on the high side but it does not seem like there's cause to worry much about organic or biological load. I'll assume being in Texas that your weather is a lot like mine and still hot. Given all that, it appears to be normal given the high temps, high sunlight exposure. Some TX pool owners consider 50ppm CYA to be the lower limit because of the extremely bright sun and high temps you guys get; I would agree with that. You could, if you want, try to bump up your CYA to 60ppm (you'll have to increase your target FC as well) to see if your daily loss decreases.

- - - Updated - - -

Another thing you could try (with some expense and great effort) is a solar cover or an opaque cover. Either of those will limit sun exposure (in the case of the opaque cover, you'll practically eliminate sun exposure) and that will likely reduce your FC loss rate.
 
Matt, I had a triangle shade suspended over the pool which would probably help cut down on the direct sunlight but I took it down since it's not 100 degrees anymore. It is still in the high 90s but for us here, that's nice weather. My water temp is still at 88. I may go ahead and bump up CYA a little to help. It seems crazy that I would lose that much chlorine every day on a normal basis. It concerns me also that it's been getting down below 4ppm but at least it's only for a little while.

PAGirl, I haven't done that. Maybe I will do that tonight just to be sure I don't have anything living. The water is crystal clear and there is no visible growth but who knows. I did do the OCLT but not at 10ppm and I didn't leave the pump running overnight.
 
Definitely do the OCLT at 10ppm and be sure everything is running.

As for a sun shade, that's a nice thing to have but its really not an effective screen of UV and sunlight. There's more than enough UV bouncing around to hit the pool. The only way to truly cover a pool and eliminate UV is with an opaque cover. Even the bubble covers let some UV through.

As for what to do in the future, you might want to consider a Stenner pump or converting to a salt water pool. Unless you're really ok with daily chlorine additions, jug-dumping is going to get really old really fast.

Let us know how the OCLT goes.


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Well I did the OCLT last night at 10ppm FC (actually 11) and left the pump running all night. This morning I had zero FC loss and 0 ppm CC. So now at least we know for sure there is nothing wrong. I believe I may have overlooked a simple explanation. I think my pool is more than 15,000 gallons. I arrived at 15k initially by measuring the oddly shaped pool and doing the math. Then the "professional" pool maintenance person I hired initially guessed 15k. Then when I drained completely and refilled the first time, the water bill showed usage to be right at 15k over last year same time. When I got home yesterday evening, FC was at 3.5, so I put that in the calculator for 10ppm target FC @ 15k gallons and added that amount (200 ounces). Waited 30 minutes and tested again, FC @ 8.5. If I change figures in the calculator to show bump from 3.5 to 8.5 @ 20k it says 202 ounces. Ended up having to add more CL to get to 10, then it was actually at 11 after testing. That would explain why I'm dipping below 3-4ppm FC at the end of the day...I never hit the goal of 6 in the first place with my morning dosing. I guess I have a 20k gallon pool.

Unfortunately, I can't get a cover because one whole side of my pool is stone at the water line and there's also a recessed "grotto" under the waterfall. I've also been told that I can't switch to salt because of the rock, but that could be misinformation. I was told the salt water would eat the rock away pretty quickly if I didn't have it professionally sealed every year.
 
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