CYA level and chlorine level and pool store recomendation

[Fishcrazy]

Thanks for the info chem geek. This floating feeder Im using is the cheapest thing I have bought for the pool so far. I wonder id there are better ones than this floating turtle or are they all this cheap. Anyhow in one day and a half the Cl level has increased 0.5 ppm. I have the floater set for a 10,000 gal pool and I hav e a 18,000 gal pool. I dont know how much control this adjustable floating dispenser will afford me but if Cl continues to rise at this rate I may have to do something different. Maybe it will not continue to rise but will reach an equilibrium at some acceptable point. We shall see in time. I plan to check the Cl levels daily.

I have read about The Liquidator and think that it may be a good solution. I however have not found a source to purchase one online or otherwise. Could you provide a link for the unit? Thanks so much for your help!

[chem geek]

If the pool is exposed to any sunlight, then the chlorine will reach an equilibrium rather quickly since the amount of chlorine added by the Trichlor is fixed but the amount of chlorine lost from sunlight is proportional to the FC level (for a given CYA level).

As for The Liquidator, you can buy it with the very much needed upgrade kit at PST Pool Supplies.

[Fishcrazy]

Well the last two days ahve FC =3.5 and seems to be holding there. I have the floater diled down to a 10000 gal pool size in this 18000 gal pool. The pucks seem to be lasting quite a while at this setting. Be interesting to see how long three of them will last in my pool. Do they suddenly get soft and dissolve faster or are they consistant till they are completely gone? Wondering if these last a week say if I could expect to be able to just go to 6 tabs for a two week period? My pH seems to be steady at 7.2 and I have not tried to raise it any. If I did raise the PH would that change anything with the amount of chlorine that I am using?

On another note I am about to install a timer for the pool pump. I have been running the pool filter 24/7 but dont feel that this is necessary. Any suggestions for a scheule for a 27 round 52 inch pool. I was thinking about 16 hours a day. Thanks in advance for any and all advice.

[chem geek]

Trichlor tabs dissolve fairly slowly and fairly evenly. They usually don't fall apart. The rate of dissolving will slow down somewhat when they get much smaller since that rate is roughly proportional to the surface area. The pH should be dropping given your fairly low TA of 50 that you last reported. Is the pool covered or uncovered? If you were to add 10 ppm FC to the pool using Trichlor and that chlorine was used/consumed at about the same rate it was being added, then the pH would drop from 7.2 to as low as 6.8 except for carbon dioxide outgassing. So normally you have the pH start out higher when using Trichlor and usually have the TA higher as well. Even if you started with a pH of 7.7, with the low TA the pH after 10 ppm FC would end up at around 7.0 if there were no outgassing.

As for pump run times, you usually figure on one turnover per day but can adjust to keep the water clear. The right amount depends on your circulation. If it's really good, you can sometimes go shorter; if not, then longer; but one turnover per day is pretty typical. Note that an above-ground pool often has terrible bottom circulation since there aren't usually many returns and there isn't a floor drain. Pointing a return diagonally downwards sometimes helps with circulation.

[Fishcrazy]

I have not run anything but the Cl test and pH since I started these Trichlor tabs on Sunday when my FC was 2.5. I dont have the pool covered but the tree canopy over the pool is considerable affording no more than 2 hours of direct sunlight per day. I guess I need to figure what the flow rate of this 1 1/2 horse Hayward is to determine the turnover time. Thanks for the tip on the circulation of the bottom water.

If Im hearing you right I need to get the TA up some more and prior to leaving the pool for the two week trip I need to make sure that the Cl is either up high around 7 or more and the pH is elevated abnormally high? I have only been feeding trichlor for 3 days and pH seems to be holding steady at 7.2. We will see what happens with tomorrow morning's water test. I think I will test the CYA abd TA also tomorrow. What would I be looking to get the TA up to? Thanks for the help again.

[chem geek]

Your few hours of sunlight explains some of what is going on -- namely that your chlorine usage is probably low. If I figure that it is only 1 ppm FC per day, then in one day the pH would only drop from 7.2 to 7.15 so not be noticeable and that assumes no carbon dioxide outgassing. If you are going to be gone for a week so we figure 7 ppm FC, then the Trichlor will lower the TA by around 5 ppm so I would just raise your TA by 10 ppm to 60 ppm and your pH to 7.7 before you leave. That will have the pH drop to no lower than 7.2 after a week, assuming the 1 ppm FC per day assumption is correct. That seems reasonable. You don't have to raise your TA way up because you'll probably be frustrated lowering it again for pH stability when you return (I assume you have the TA very low for pH stability when using bleach or chlorinating liquid -- if not, then raising it to 80 ppm would be OK).

[Fishcrazy]

Today the water test surprised me a bit. pH=7.0, FC=3.5, CC=.5 or less, TA=40, CYA= 30. Surprised to see the CYA down a bit especially since adding trichlor. But it is what it is. I am going to raise the pH to around 7.4 to 7.5 and the TA to around 60 and see what happens from there. I am beginning to think I will not be able to make it two weeks at the time away without some intervention by someone to add some chemicals to bring the pH up or maybe I could raise the pH to say 8 when I left and expect the decrease of 0.05 per day to bring me to pH = 7.3. Would there be any danger in taking the pH to 8 right before I leave? TA seems to be falling rather briskly. Looking like a raise to 80 would be a good Idea prior to taking off. Maybe higher? I am not intentionally keeping TA down as I did not know that a low TA would promote pH stability when using bleach. I was under the impression that my TA needed to be raised from my initial levels to promote stability in pH. Glad I got that straight. What would be a good TA level when using bleach? Thanks chem geek! I really appreciate the insights you are providing.