Use Pool Math, at the bottom of the page Effects Of Adding Chemicals, it will tell you how much X amount of dichlor will raise FC and CYA. ?
Problems with refilled pool: Water turned green after adding chlorine
- Thread starter Christian B
- Start date
Taylor TF-100.
Yes, I saw that in the pool calculator. But I don't know if the granulated chlorine I bought has the same amount of CYA.
Let's hope it's the same.
Pool math has a usefull option on the bottom called Effects of adding chemicals shows what levels change when you add any single chemical ive been doing the same as you are doing with CYA but using Trichor just writing down every time i add some trichlor untill i get somewhere near then i will test it (hopefully my test kit will of arived by then ) im in the same situation i live out in he coutryside in NE thailand so shipping is expensive .
The problem with doing it that way is when you put the weight of the trichlor tab. That will give yoy the amount of fc that will have been put in by the time it is dissolved, which when tested won't even be close to what you expected since fc is being constantly used up. What can make that relevant is "if yoy know precisely how long it takes to dissolve each individual tab. On the other hand, dichlor granules which are quickly dissolved will be much more relevant to knowing how much you're putting in.
I forgot to mention im not using Tabs im using Granules i do have a tab feeder but wont be using it anymore unless im away for a few days 
I'm not sure if there's some confusion floating in this thread about the amount of CYA in dichlor -- I think someone asked if a percentage of CYA was listed on your particular product label.
Anyway, the dichlor is a chemical compound, so that inherently sets ratios of the materials we're interested in for pool chemistry (the chlorine and the cyanuric acid). It's not like a mix of salt and sugar, for example, where you could have 10% salt and 90% sugar, or 80% salt and 20% sugar, or... any other ratio you like. It's more analogous to the ratio of hydrogen and oxygen in water -- that ratio is fixed by the chemistry of the molecule.
I don't remember for sure if there are different forms of dichlor (I'll post a link if I come across something). You can search the forum yourself, and perhaps someone more knowledgeable about chemistry will chime in also.
edited: below is a quote from chem geek, including the info. about the two forms of dichlor (dihydrate and anhydrous):
***********************************************************************
It doesn't work out that way for several reasons, but mostly it's because Dichlor has TWO chlorine atoms attached to the ring so it's one part CYA and two parts chlorine. Trichlor has THREE chlorine atoms attached to it so it's one part CYA and 3 parts chlorine. But the "ppm" values don't work out exactly because the ppm for chlorine is for the weight of chlorine gas which has TWO chlorine atoms. Another factor is that the most common form of Dichlor has two water molecules attached to it (dihydrate).
Dichlor•2H2O is 255.97766 g/mole
CYA is 129.075 g/mole
Chlorine gas is 70.906 g/mole
Trichlor is 232.4103 g/mole
Dichlor anhydrous is 219.9471 g/mole
So, Dichlor (dihydrate) is 129.075/255.97766 = 50.4% CYA and 2*70.906/255.97766 = 55.4% "available" chlorine.
Trichlor is 129.075/232.4103 = 55.5% CYA and 3*70.906/232.4103 = 91.5% "available" chlorine.
Dichlor anhydrous is 129.075/219.9471 = 58.7% CYA and 2*70.906/219.9471 = 64.5% "available" chlorine
129.075 / (2*70.906) = 0.91
129.075 / (3*70.906) = 0.61
Anyway, the bottom line is that for every 1 ppm FC added by Dichlor, you get 0.9 ppm CYA while for every 1 ppm FC added by Trichlor you get 0.6 ppm CYA.
I have added 1.100 grams of dichlor so far, which should have raised CYA by 13.
It's getting slower now, because FC is maxed out (at 10) and the chlorine last longer with the higher CYA.
It's getting slower now, because FC is maxed out (at 10) and the chlorine last longer with the higher CYA.
1.1 kg maybe? OK, I see -- you are using a decimal point (different convention) where people in the US are more accustomed to a comma (1,100 g = 1.1 kg). I've often wondered how these different uses of "." and "," came about in different parts of the world. Certainly a source of potential confusion!
I'm still raising CYA with dichlor, but the pool got crystal clear after about a week with high FC levels.
