Assistance with balancing....?

[usedtobeayooper]

New to this forum and would appreciate input on helping return my water to balance…

Prior to this year, I had a 5200 gal polygroup pool that I’d take down every winter. Never had an issue balancing.

This year, it started off the same after installing a new 7600 gal above ground pool that I intended to leave in place year round.

Until… I learned the hard way that CYA isn’t like every other chemical… it never goes away, pucks make it worse, and more isn’t better.

So…. long story short, I chlorinated with pucks and powders all summer and thought I had the pool nice and balanced, clear, and beautiful, until I recently noticed the CYA going too high. Further testing had it upwards of 200 when doing a ½ reduced sample using my Taylor test kit.

After some extensive reading, and a much better understanding of CYA, I have so far drained and replaced about 24” of water and am seeing a dramatic reduction in CYA…. But my PH is on the low side of the safe window and my Alkalinity is too high.

Current Test Results:

Hardness – 220
TC – 5
FC – 3
PH – 7.2
TA – 180 Taylor test => 180 – (90 x 0.27) = 156 actual
CYA – 90

Should I… A, Continue to drain/re-fill until I get CYA down under 50, and then adjust Alkalinity, or B, Correct Alkalinity and THEN finish correcting CYA?

My thought was to add 29 oz of 14.5% Muriatic Acid (per the calculator) to reduce the alkalinity. This would also theoretically drop PH to 7.0. I would then drain and replace another 24” of water, which would help aerate the pool and hopefully help raise the PH while cutting the CYA in half to 45-50.

Any and all input is appreciated.

 

[justinc]

Total chlorine of 5 and free chlorine of 3 equals combined chlorine of 2 which means you should SLAM the pool (if those numbers are accurate). What test kit are you using because the K2006 or TF100 don't give a total chlorine result... they give a free chlorine and a combined chlorine result.

SLAMing with a CYA of 90 is impractical. Replace water in pool by half and re-test values and adjust before SLAMing.

Don't add any chemicals until you have lowered your CYA.

 

[Flying Tivo]

You need to drain at least 1/2 if not 3/4 or the pool water. If you drain by half then you wont be able to use pucks for vacations. Go for 3/4 drain. Dont add any more chemicals as it would be a waste.

 

[usedtobeayooper]

Total chlorine of 5 and free chlorine of 3 equals combined chlorine of 2 which means you should SLAM the pool (if those numbers are accurate). What test kit are you using because the K2006 or TF100 don't give a total chlorine result... they give a free chlorine and a combined chlorine result.

I have the Taylor K-2005 (Complete) test kit. The directions walk you through first testing for Free Chlorine, then adding additional drops to test for Total Chlorine, and then states to "Subtract Free Chlorine from Total Chlorine" to obtain the Combined Chlorine (CC) reading."

 

[mknauss]

Welcome to the forum!
The K2005 kit is missing the FAS-DPD test to accurately measure FC and CC.
You can get just the FAS-DPD at FAS/DPD Chlorine & CC's test
I suggest you read ABC's of Pool Water Chemistry.

 

[usedtobeayooper]

Also, I will continue to drain and re-fill and will update once I get the CYA down. My problem is that draining it takes forever by syphon and I don't want to run my submersible pump unless I'm home.

Yesterday I ran home and started the syphon at lunch, and when I got back home last night after work (6:00 ish), it had only drained 3 inches. Added the submersible and managed to get another 3 inches out of it before I re-filled it high enough to run the pump over night. I understand that small drains make the process slower than one big drain, but I also fear that going too long without the pump/filter running isn't a good idea either.

Plan is to start syphon over night on Friday, add the pump Saturday morning early, and see how low I can get it with that process all day..... unless is really nice out. My daughters would kill me with so few pool weekends left in the season.

 

[usedtobeayooper]

Welcome to the forum!
The K2005 kit is missing the FAS-DPD test to accurately measure FC and CC.
You can get just the FAS-DPD at FAS/DPD Chlorine & CC's test
I suggest you read ABC's of Pool Water Chemistry.

Thanks! I will order that kit today.

Out of pure curiosity and for better understanding on my part, can you explain what the difference is? I'm not doubting your assessment what-so-ever, I'm just confused why the test included in the K2005 does say that it tests for Free Chlorine, while you're saying it doesn't. Or is it more a matter of the actual "accuracy" of the test that the K2005 contains?

 

[mknauss]

The K2005 is a color comparison test for FC and a sort of back into it test for CC.

The FAS-DPD uses a powder and titrating reagent to do the test. The sample turns pink with the powder and the titration results in no color. So you have a real value based on number of drops of reagent, not a guess of a color.

 

[usedtobeayooper]

The K2005 is a color comparison test for FC and a sort of back into it test for CC.

The FAS-DPD uses a powder and titrating reagent to do the test. The sample turns pink with the powder and the titration results in no color. So you have a real value based on number of drops of reagent, not a guess of a color.

Thank you!

 

[SteelBlue]

When I need to siphon my pool I use a pool vacuum hose (2"diameter), works fast.

 

[usedtobeayooper]

When I need to siphon my pool I use a pool vacuum hose (2"diameter), works fast.

Thanks for the head's up. I considered this earlier, but didn't think I could get the water to a safe discharge location with only the 25-ft hose I had.... but I was wrong. Tried it last night when I had a chance and was able to drain about 8" in just over an hour! Will definitely speed the process.

My current readings prior to draining/re-filling last night were:

TC – 10*
FC – 10*
PH – 7.2
TA – 150
CYA – 80

*Per the above advise from mcknauss, I have a FAS-DPD kit ordered, but it hasn't arrived yet, so in the mean time I've been doing my best to maintain FC in the 10 range (per the Chlorine/CYA Chart) using the K2005 color comparison test until it arrives.

 

[usedtobeayooper]

So, I received my FAS-DPD kit yesterday and ran a whole slew of tests to both practice my consistency and to get a decent average. (I learned in doing so, that swirling that many times is a pain, so I also ordered a speed stir.)

As an average, I continually came in between 22 and 26 drops for the FC test, or 4.4 to 5.2 FC. Because it was raining (hard) outside, my method was to take a large 24 oz sample with a sample container and then run into the garage where it was dry. I’d dip smaller 25 ml samples out of that container to fill the test cylinder and then run my test. What I found odd, was that with each successive test my drop count would almost always decrease. For instance, first test 26 drops, second 25 drops to clear, 24 third test, etc. Run back out, rinse the container in the pool, grab another sample, repeat. And again I’d be around 25-26 drops the first time, decreasing a bit each time thereafter. I’m chocking the decrease up to minor contamination of the larger container with each test (?), and using my initial test of 26 drops as the number, as in most cases, the first test out of a new sample was always 25-26. Does this sound normal?

As for CC, the sample would always turn a faint pink when I added the next reagent, and then clear up in only 1 drop (2 in once instance), so I’m calling it 0.2, or negligible. Sound right?

Total results:

FC – 5.2
CC – 0.2
PH – 7.4
TA – 150
CYA – 50 (after extensive drain/re-fill)
CH – 220 (I did not retest last night, but this is where it’s steadily been forever)

I added 35 oz of liq. Chlorine (10%) per pool math to get me up to about 8 ppm and called it a night.

Looking at these numbers, would you bother trying to adjust PH or TA, or just slowly allow the PH to rise on its own and just admit that my TA is a tad high? The pool is perfectly clear, comfortable, and I’ve had zero signs of algae, etc.

I do intend to push towards 30 on the CYA, but with the year ending and the pool warm, I’m going to just live with it until I close, when I’ll subsequently drain off some over the winter anyway. Reasonable?

 

[frogabog]

You can use the 10ml sample for FC. Each drop is .5ppm. That's good enough precision for your purposes.

I wouldn't mess with anything till you see if pH rises on it's own. Then you can use muriatic acid to lower pH and that will work on lowering TA as well. You could aerate to raise pH if you want to speed up the process. I'd wait and see what happens for a while yet though. 7.4 is just fine and Pool Math gave you your target.

Nicely done!

 

[usedtobeayooper]

Received my speedstir last night... first impression: "how did I live without this thing"... sure made it easier to run a ton of tests with very repeatable results.

Currently sitting at:

FC – 8
CC – 0... maybe 0.2...*
PH – 7.4
TA – 160
CYA – 50
CH - 160

*Ran the test 5 times, on only one of them did the sample turn VERY slightly pink when adding the R-003, and it cleared up with 1 drop (25 ml test).

A few notes:

My well water has a TA of 170, so not surprised my levels bumped up a bit with the recent fill water.

Also, part way through re-filling, I noticed that the hose spicket that I was using runs through my water softener... so also not surprised to see the hardness level drop.


I would like input on the numbers and any feedback or suggestions. Feel like it's pretty dialed in except the TA. Would you bother adjusting that down, since I really haven't experienced any ill effects? Pools clean, clear, and comfortable and PH has been pretty consistent.

Will a high TA adversly affect closing in a few weeks as temps begin to drop off here in Michigan?

 

[justinc]

If your pool is plaster, raise the hardness to 250. If fiberglass, 220. If vinyl or above ground, ignore.

When pH hits 8.0, lower it to 7.2 with muriatic acid. This will lower total alkalinity over time. You will notice that since your total alkalinity is on the higher side, it will cause your pH to drift upward and you will be adding acid more frequently. Eventually the pH will stop rising or slow down and at that point, you will have found the ideal total alkalinity level for your water to keep your pH in range. Some people go months/weeks without having to add acid. You will notice with your total alkalinity at currently high level you will probably need to add acid more often.

Otherwise enjoy your pool.

 

[usedtobeayooper]

If your pool is plaster, raise the hardness to 250. If fiberglass, 220. If vinyl or above ground, ignore.

When pH hits 8.0, lower it to 7.2 with muriatic acid. This will lower total alkalinity over time. You will notice that since your total alkalinity is on the higher side, it will cause your pH to drift upward and you will be adding acid more frequently. Eventually the pH will stop rising or slow down and at that point, you will have found the ideal total alkalinity level for your water to keep your pH in range. Some people go months/weeks without having to add acid. You will notice with your total alkalinity at currently high level you will probably need to add acid more often.

Otherwise enjoy your pool.

My pool is AG vinyl... so assume I'm good on the hardness. Any advantages to intentionally raising back to 220 where it had previously always sat steady from my usual fill water? Pool feels great now, just curious.

Also, I know MA is the preferred PH reducer around here, but any harm in using up the 1/2 lb of PH- (sodium bisulfate) I have on hand? Or should I just pitch that and go MA? Not worried about the cost, just perfer to use it up vs dispose if it's acceptable.

 

[mknauss]

No advantage to adding calcium to your pool.

You can use up that small amount of sodium bisulfate. Just do not continue to use it. Sulfates can harm your heater.

 

[usedtobeayooper]

If your pool is plaster, raise the hardness to 250. If fiberglass, 220. If vinyl or above ground, ignore.

When pH hits 8.0, lower it to 7.2 with muriatic acid. This will lower total alkalinity over time. You will notice that since your total alkalinity is on the higher side, it will cause your pH to drift upward and you will be adding acid more frequently. Eventually the pH will stop rising or slow down and at that point, you will have found the ideal total alkalinity level for your water to keep your pH in range. Some people go months/weeks without having to add acid. You will notice with your total alkalinity at currently high level you will probably need to add acid more often.

Otherwise enjoy your pool.

So... following up this...

Current conditions:

FC – 8
CC – 0
PH – 7.4
TA – 160
CYA – 50
CH - 160

Which is almost exactly where I've been since its stabilized and I've completed exchanging water back August. Still intend to drop the Cya this fall when I close, have just been happy for now where it's at vs add more 56 deg fill water.

Otherwise I've just added lq. 10% chlorine. Nothing else.

My PH has been rock steady. As has been my TA. Should I try to lower my TA anyway, or is it fine since its steady?

 

[mknauss]

If your parameters are steady, no need to address the TA.

Good job.

 

[usedtobeayooper]

If your parameters are steady, no need to address the TA.

Good job.

Thanks for your help through the process!