General start-up question

[NeedMoreSun]

My new K-2006 kit should be here tomorrow and I will soon have more specifics, but this is somewhat a general question anyway.

The pool with the house we purchased has been using chlorine pucks placed under the strainer baskets weekly for at least 2-3 years. When I had them test CYA they said it was about 90. Since that's just a little high do I need to worry about bringing it down before completing the conversion? Otherwise, I was thinking I'd just adjust the desired FC levels and with no more pucks in use adding to the CYA it would slowly drop anyway? I forgot the rest of the results I had them take, other than most were all within, or at least close, to what's listed in the sticky and in pool school.

Related question is I'm also now ready to convert. Everything is now running on my new pumps, filter, and even a new pad. I HAD intended to time it for just before the pool service came out and would add more pucks but just tell them to stop doing that, then turn on the SWG and monitor daily, add bleach as needed and keep adjusting. Tired of the weekly major swings in chlorine as well anyway. But, we now suddenly have company coming to visit for a week in a couple of days (see what happens when you move to Florida). With a sudden extra bather load would it make ANY sense to just get the SWG running, even if at a low level to help a little with the extra load? Still watch it daily to be sure nothing TOO high, but basically just complement the pucks? LOL, one of the visitors is a 3 year old, so there will for sure be some extra bio-load there!!!

Otherwise, with weekly addition of pucks and the pool service basically guessing, even by their own test FC fluctuates from as low as 3PPM to as high as 12 !!!! I didn't like the 12 at all, and the response was "All's good, commercial pools go much higher!". Except I don't have a commercial pool

 

[Texas Splash]

Well, hello there! There are a few variables in your scenario, but honestly, until your kit gets here it's a guessing game. I suspect that with all the years of pucks and tablets being used, your CYA may be exceptionally high and require a partial drain to recover. You may try to increase FC via your SWG and/or liquid bleach, but it's still all a guess right now. I would suggest not doing anything too drastic until your kit arrives and you post some good numbers.

 

[NeedMoreSun]

Yeah Thanks for the reminder. It will also not be a normal load and a bad time to be trying to dial in my normal settings. Even with the kit I'm likely safer to just remove those pucks, test nightly, and use bleach until the company is gone and then go right to firing up the SWG under a normal load.

I was just thinking HAVING an SWG now I could use that if with the load the FC falls and the excitement of it doing something, lol. Patience is needed though Would never know I had large marine reef tanks for many years and managed patience on those

 

[NeedMoreSun]

Uh oh Either pool guy can't use his own tests or I'm doing something MAJORLY wrong..

CYA.. 7 ml, add the regent to 14 ml and shake. Add it to the little side of comparator until dot is gone. Ummm, not even CLOSE to the 100 mark and the dot is gone. Long gone. So, unless I missed something, how does pool guy come up with the 80-90 he usually reports?

Sheesh I see lots of draining in my future

FC 14
CC Not sure of my eyesight on this one, may be zero but a "slight" pink tint gone in two drops so 0.4 max
Ph 7.3
TA 70
CH 180
CYA ummm, off the chart

Unless I'm missing something, the CYA test seems the most straight forward of them all and I'm WELL over 100 and Texas Splash was spot on about my CYA likely being much higher I really, really, really wanted him to be wrong though!!! lol

Anyway, no converting today, and getting even more irritated with the pool place if my FC is accurate. That's to much with my grandson here tomorrow!!

Hmmmm, now what?

 

[Texas Splash]

So your kit arrived huh? CYA higher than you anticipated? I suggest a cold beverage. It's not going anywhere. Relax and enjoy time with your grandson.

 

[NeedMoreSun]

It didn't even get CLOSE to the 100 line and that dot was gone I'm still perplexed how the pool guy can continually report much lower numbers unless I somehow did it wrong myself, but it was the easiest of all the tests so I can't see how. He also seems to manage to never be seen actually doing the tests though I walk away and when I'm back he has results. I think a pool service is getting fired soon unless they can show me how they came up with those numbers

Otherwise, other than not even trying to fire up the SWG yet would it be a bad idea to start changing water each night even when company is here?

 

[Texas Splash]

If you are confident in your CYA testing (and it sounds as if you are), then sure. You can do partial drains in stages. Shoot, don't be surprised if after the drain(s) you see new CYA numbers and the pool guy's never changes.

 

[Scuba_Steve]

Try the dilution method.

http://www.troublefreepool.com/thre...Kit-Directions?p=203524&viewfull=1#post203524

Post # 8, Bullet # 9

Oh and I know exactly how the pool guy gets his readings. He throws a dart at a CYA level dart board. He must have some accuracy to hit the same spot every time!

Also, just in case. If the dilution method still tops the scale, do the double dilution method. Fill, lower to half. Fill again, and lower to half. Then add CYA reagent. Multiply x4.

 

[NeedMoreSun]

Thanks Scuba_Steve!!! I'll do that tomorrow and hopefully at LEAST know where I'm starting at with more accuracy than "More than 100", lol.

 

[NeedMoreSun]

It read 70 using dilution so CYA is 140
I think my water company is going to like me.

 

[Texas Splash]

Uhg. Well, at the very least now you know. Better to be in control of your own pool destiny.

 

[NeedMoreSun]

Well, how far should I bring it down before even bothering to finish bringing the salt up and using the SWG? Is there any impact of high CYA other than the correspondingly high minimum FC?

I obviously want to bring it down some, and I'd at least like it within the 100 scale. My only thought is there has been years of puck usage and those will no longer be adding more and with an annual rainfall of 64 inches combined with refilling after backwashes it will slowly keep falling on its own wouldn't it? Eventually needing to increase it?

Well, that assumes my SWG can keep up without ridiculous run times but I have a T-15 on only a 15,000 gallon pool so I hope I'd be ok and I have the VSP running now to keep my electric costs a little better

Kicking myself for taking his word on where it was. Wife works in lawn and garden at Walmart so has been buying up their 50% on ripped bags of salt and then her discount on top of it for months and we've been adding it and were finally within just two bags of hitting 3200 ppm and now I'm diluting it already, lol !!!!

 

[Texas Splash]

I understand totally. Well, I'm honestly not a SWG user, but we all now that they do have a limited service life. That's why (for example) we recommend users turn theirs off during a SLAM, or at the very least let the bleach "augment" their operation during peak FC periods. You may very-well find yourself in that same position until such time you can get the CYA lower and/or more manageable for the SWG.

I'm sorry I can't give you a specific % rate to dial your SWG to at the moment based on your high CYA, but don't be surprised if another TFP SWG owner replies. Many people watch these threads. If it were me though, knowing the CYA is through the roof, I would probably try to save some SWG service life by dialing it down to a somewhat normal usage rate and augment with liquid bleach to assist in your FC level. I know that defeats the purpose (independence) of an SWG, but that's just me. You only have so many options right now. Keep checking back in case others have more suggestions. Like my wife says, I don't know it all.

 

[NeedMoreSun]

LOL, no problem Texas and thanks for all the help and sympathy thus far

For setting the SWG though if nothing else I'll be taking a wild guess and be testing daily as I adjust it, but it would be a bummer to AFTER the fact find it can't keep up. I'm not leaving it at 140 either, I want it at LEAST in testable range before relying on mother nature to keep bringing it down more. Pool calculator shows 36% of the water to get it to 90. Not all that bad I guess, other than right now I can't simply drain that much and have it out of commission while it refills but already have the hose running. For now I'll likely just dilute it 5-6 inches at a time and drain it off when the skimmers are swamped.

 

[Texas Splash]

Sounds like a good, solid plan. I hope the water exchange helps get you back in the ballpark soon. Enjoy your day.

 

[NeedMoreSun]

Nine hours until our kids arrive for the week. Hose has been running awhile now and to the top of the skimmers. However, during storms we have come close to overflowing and I always wondered which direction it would go first and may just let that hose keep going to find out I won't be able to change more than small amounts at a time once they are here and people using the pool. Sounds fun anyway, lol.

 

[swoopman]

Be prepared to supplement the SWG with bleach. If you've looked at the FC/CYA chart you know the FC number of 14 is not high with the CYA you have.

 

[NeedMoreSun]

Yep, we have bleach on hand. This wasn't the initial reason though, lol. I was planning to use bleach to complement the SWG until I got it dialed in, and instead diluting what I have

On a side note, as I do dilute it, is it reasonable that as I dilute the CYA the FC will dilute at an approximate level as well? The pucks are still under the strainer baskets as well right now. Without doing any math I was just thinking though that any reduction I cause in FC will also reduce CYA and need less anyway. Regardless, I'll check FC daily. AFTER company is gone I'll retest CYA and then actually just drain whatever amount is still needed to get it in line, although I'm only shooting for 90.

 

[swoopman]

You're going to loose FC to the drain & fill but also to sunlight and bather load.

There are still pucks in the pool so CYA is still being added.

According to Chem Geek:
"The 3" pucks unfortunately vary in weight being 6, 7 or 8 ounces (there are also 1" 3-ounce tabs and 1/2" 1-ounce tabs). If I assume 8-ounce pucks, then one in 10,000 gallons adds 5.5 ppm FC and 3.3 ppm CYA. The general rule regardless of puck weight or size is that for every 1 ppm FC you add using Trichlor, you also increase CYA by about 0.6 ppm (note that 55.5% / 91.5% = 0.61)."

Some rough numbers - let's say 3 pucks is roughly 10 CYA. According to Pool Math to drop 10 CYA (from 140 to 130) you'd have to drain 7% of your water - 15,000 x .07 = 1,050 gallons. So if you think you've drained that much water then all you've done is break even on CYA if you use 3 pucks. If you've drained more then the CYA may have dropped a little but not likely within the accuracy of the CYA test (+/- 10ppm, less accurate when doing a diluted test).

According to this thread on FC/CYA relationship:
Chlorine/CYA Chart
"Min FC" is 7.5% of the CYA level
"Target FC" is 11.5% of the CYA level
"Shock FC" is 40% of the CYA level

Maybe this info can help limp the pool through the week while you have company without resulting in an algae outbreak - it can happen quickly if the FC gets too low. I would test FC at least twice a day if it were me.

 

[NeedMoreSun]

Twice a day it will be then

Looking at the charts, and the pool calculator, would maintaining FC at 10 seem reasonable? Knowing my CYA should be dropping, but at worst is at least the same? Otherwise, it's easy enough for me, I'm on vacation and the pool enclosure is also my smoking area so I can test it each morning while having my coffee and a smoke and then again sometime in the evening if nobody is in the pool

"Limp along" is an appropriate description. Other than we have no current issues either, so I don't want to blow it up