Followed Pool Calculator, unexpected results?

[amjohn]

New pool finally in- finished filling and turned on pump last evening at6:30pm- water a little cloudy and a tad greenish, but not bad- that is how it comes out of the faucet here in rural North Texas. So time to add chemicals. Using TA-100 test kit.
Starting water values in the pool before chemicals:
FC=1
CC=2
TC=3
ph=7.6
T/A=80
CH=70
CYA=0
Temp- not sure, but a very pleasant compared to 100 degree air temp.
Started with 2lbs of di-chlor that we had on hand to get the ball rolling. Wanted to shock out the CC's and any algae that might be getting started and get some CYA in the pool.
According to pool calc- 2lbs of di-chlor in a 20,000 gal pool should raise FC by 6.6, raise CYA by 6, lower PH by -0.25, and raise Salt by 5.
Sure enough- the ph and T/A dropped rapidly to 6.8 and 40-50 respectively. The CYA level is still too low to register on the TA-100 test, so cannot confirm that. And the water did get much clearer.
But what confuses me is that FC did not test higher than 4.5 and an hour later was back to 3.5. CC did drop to .5. After a couple hours of testing, it was way late- so we added a 2lb box of baking soda (all we had on hand at the time) and 2 cups of 65% of cal-hypo to the skimmer and went to bed, leaving the pump/filter running.
This morning, under cloudy skies and "only" 90 degree air temps at 10:30AM, my results are:
FC=4
CC=.5-1 (see below for why I am uncertain about this)
TC=4.5-5
ph=7.2
TA=60
CH=70
CYA= still not enough to register.
And, the water is cloudy again, but no green tinge.
( It has just rained briefly for the first time since early June (of course ), and now the sun is out, and it it supposed to repeat that cycle all day today, so these numbers will probably change.)
So, what happened. Why did the chlorine not go up to as high as expected?

CC Uncertainty: Also, a little side question about the CC drop test- I add the reagent for that test- 1 drop, and the solution turns clear. That makes my CC=.5. I put down the vial to move on to the TA test, and few minutes later, notice that the Chlorine vial has turned a light pink again. So I add another drop of the reagent, and it turns clear again. So is my CC now 1, or is this a normal thing and I am just supposed to go with my initial 1 drop?

 

[JasonLion]

FC gets consumed by various things. Getting rid of CC uses up FC. With CYA around 0, FC goes away very quickly from sunlight, even indirect sunlight. Any organic material in the water will get oxidized, using up FC. Anyone swimming will use up a little FC.

The FAS-DPD test will turn pink again if you leave it alone for a minute or two. Ignore that.

 

[amjohn]

Why is my pool cloudy again this morning?
And what next? I am going to the pool store this after noon to get CYA. I have 25lbs of 65% Cal-hypo. Anything else I need to do right now, or should I just wait a couple days and see how it plays out?
I am planning on getting a Chlorease Ultra salt water generator (a number of pool users in this area have been very happy with them) , so the goal is to get my pool balanced at the required readings before I put it in- FC=1-4, ph=7.2-7.6, TA=80-100, CH=150-300, CYA=80, metals=0, and of course Salt, but not adding that until the other things are balanced.
Our water and ground, and probably our air, is alkaline, so alkalinity will come up on its own, the cal-hypo will bring up the CH, and I am going to add CYA this evening. Anything else?

 

[JasonLion]

You will want to keep your TA and CH levels at the bottom of the ranges you quoted.

It is difficult to say what is causing the cloudiness. I suggest bringing FC up to 10 tonight, then test in the late evening and early morning and see if the FC level stays the same overnight or not.

 

[amjohn]

Can I add the CYA at the same time as adding the Cal-hypo shock or should I shock it tonight first, then add CYA in the morning? I don't need to backwash any time soon.
Also, according to the Pool Calc- I need 25oz by weight of the cal-hypo to get FC to 10. But when I go to the bottom of the table and check the cal-hypo addition, it says 25 oz of Cal-hypo will raise FC by 6, raise CH by 4, and raise Salt by 6. Why is there a difference between the two parts of the pool calc on what the FC will be using the same amount of cal-hypo?

 

[JasonLion]

You can go ahead and add the CYA any time.

I get the results you describe in my Pool Calculator if I set the current FC level to 4. The Effects of adding chemicals section is telling you that 25 oz will raise the FC level by 6, ie from 4 to 10, not that it will raise FC to 6.

 

[SPP]

Hello John,

In my country the city water is "slow", it will take a week or more if I fill my pool up with it and I may not get water for my home...... Dang this is the norm for a poor country. So I have to buy city water or sometime they claimed is spring water using 2K gallons trucks...anyway its always light green at best before treatment.

Usually it takes up to a week to make the water clear with the pump running 24/7 with my main pump measured at 12 hours per turnover. Be patient, it will take a few days at your pool size with 1.5Hp pump and that must be runned non stop. Jason have explained to you the chemistry, I want to let you know that real filtration of particles will take a long time pumping. Even if your pool is calculated to do 5 hours per turnover, in reality you will need 5-7 times that turnover to get 100% of the water in your pool to be actually filtered. This is not to mention if your sanitizer is still killing contaminants and thus cloudy water gets introduced again and again while filtration is doing its work.

The cloudy to sparkling process is the most time consuming for my pool and probably for most pool. I mean in terms of contamination weight in pounds removal against pump running hours. Many cloudy pool, probably is from very fine particles, even with my back up pump running a 1 micron filter and my main pump also running, it still takes time. My main pump is 3 micron rated for the sand because I use Zeolite media and I added 20 micron cartridge downstream, still cloudy water correction is always time consuming and can not be done in less than 5 pool water turnover to get good result.

I say that the particle is fine because I do not get increase in pressure on the filters from restrictions but after say 5-6 water turnover...then the sparkling water will come. Time...time, please be patient. A pool is not like 2 seperate containers we use for filtering other liquids. ...be patient.

Regards,
SPP

 

[amjohn]

Thanks for the encouragement. Unfortunately, we are having lightening storms right now, so I had to turn the pump off until they pass. Bad water is such a pain. The FC got consumed during the day, and it is raining (or actually "dirting" as the air is so full of dust this time of year that the rain is bringing down more dirt that water), so I guess I will start again tomorrow to get some stabilizer and chlorine in there and run the pump for a couple more days.

 

[amjohn]

OK, well now I am confused. I turned the pump back on and shocked the pool this morning to a goal of 10 (based on the pool calculator) using 65% Cal-hypo dissolved in pool water in a bucket and then poured in front of the return. I also added 6 lbs of granulated CYA to the skimmer -the first CYA addition-and 2lb of baking soda to the skimmer, as TA and Ph had drifted down a little.
My test results about 1.5 hours after the additions:
FC=10.5
CC=.5
pH=7.2
TA=90
CH=80
CYA= not registering yet
Pool water cleared quickly, having been a little cloudy
That was at 10:30AM under heavy cloud cover and 80 degrees. The sun started peeking out around noon, and temps rose quickly into the 90s. It is now 6PM, the sun has been out for a while and it is about 92 degrees, with pool water at 86 degrees. The pump has been running all day.
I just retested, and the FC has only dropped down to 9.5, with the other numbers remaining the same. According to everything I have read on the forum, the lack of CYA combined with bright sun and warm temps means that FC should go away rapidly. Yet it has been stable pretty much all day. I guess this is a good thing, but what does it mean? Did I not need to shock after all? Did I overshock? I just want to understand how this all works.

 

[frustratedpoolmom]

OK, well now I am confused. I turned the pump back on and shocked the pool this morning to a goal of 10 (based on the pool calculator) using 65% Cal-hypo dissolved in pool water in a bucket and then poured in front of the return. I also added 6 lbs of granulated CYA to the skimmer -the first CYA addition-and 2lb of baking soda to the skimmer, as TA and Ph had drifted down a little.
My test results about 1.5 hours after the additions:
FC=10.5
CC=.5
pH=7.2
TA=90
CH=80
CYA= not registering yet
Pool water cleared quickly, having been a little cloudy
That was at 10:30AM under heavy cloud cover and 80 degrees. The sun started peeking out around noon, and temps rose quickly into the 90s. It is now 6PM, the sun has been out for a while and it is about 92 degrees, with pool water at 86 degrees. The pump has been running all day.
I just retested, and the FC has only dropped down to 9.5, with the other numbers remaining the same. According to everything I have read on the forum, the lack of CYA combined with bright sun and warm temps means that FC should go away rapidly. Yet it has been stable pretty much all day. I guess this is a good thing, but what does it mean? Did I not need to shock after all? Did I overshock? I just want to understand how this all works.

I wouldn't worry about it, being able to keep your FC during the day is a good thing....

Wait about a week before you retest the CYA, you'll just use up your reagent. It can take several days for it to fully dissolve in your filter and start registering, just keep the FC up. Your TA is fine, but your PH is a bit low, I would point your return eyeball up towards the surface so that the bubbles break the water and cause aeration. This will raise your PH, without adjusting the TA at all. Retest your PH after several hours to see what kind of increase you get, shoot for 7.6. The cover must be off when you do this. BTW, You should run your filter 24/7, till everything is clear and your test results are in the recommended levels.

 

[amjohn]

Thanks pool mom. I am running the filter 24/7 as I am able, but since the electrician (my husband) has not got around to setting up power to the pool yet, we are running off 10-gage extension cords duct taped together and plugged into the back porch exterior outlet. This weekend is supposed to be electricity installation weekend. Until then, we have to turn off the pump and unplug the system when we get lightning and/or rain for safety. Oddly, this would not normally be a problem this time of the year, but we are having a little surprise "cool" spell- daytime highs in the low to mid 90s, nighttime around 70 degrees.
I am not using a solar cover right now- our water is 86 degrees without one. Won't need a solar cover until end of Sept. Soon enough, the 100 plus degree temps will be back and the water temp will shoot up to 96 degrees. Then we will put in a fountain and aerate to keep it the water temp down, hopefully to 86 degrees. My logic in keeping the pH a little low right now is that the daily fountain running will be starting any day, and then I will be fighting to keep the pH down, so I am keeping the pH "in reserve" so to speak. Does that make sense?

 

[frustratedpoolmom]

Thanks pool mom. I am running the filter 24/7 as I am able, but since the electrician (my husband) has not got around to setting up power to the pool yet, we are running off 10-gage extension cords duct taped together and plugged into the back porch exterior outlet. This weekend is supposed to be electricity installation weekend. Until then, we have to turn off the pump and unplug the system when we get lightning and/or rain for safety. Oddly, this would not normally be a problem this time of the year, but we are having a little surprise "cool" spell- daytime highs in the low to mid 90s, nighttime around 70 degrees.
I am not using a solar cover right now- our water is 86 degrees without one. Won't need a solar cover until end of Sept. Soon enough, the 100 plus degree temps will be back and the water temp will shoot up to 96 degrees. Then we will put in a fountain and aerate to keep it the water temp down, hopefully to 86 degrees. My logic in keeping the pH a little low right now is that the daily fountain running will be starting any day, and then I will be fighting to keep the pH down, so I am keeping the pH "in reserve" so to speak. Does that make sense?

If you experience PH rise from the aeration caused by using the fountain, it will help to lower the TA to around 70 or so, then you won't see the PH rise as much....good luck with the wiring, what a pain....