CYA still high after water change

[fcfrey]

Are you sure you are using your kit properly??!!

I have 2 different kits, 1 is part of a Taylor kit. Directions for that kit uses 7ml pool water and add another 7ml of 0013 reagent in a seperate tube----You shake and wait then add the mix slowly in the tube with the black dot on the bottom until the dot just disappears--then read the mark at the water level..100 is near the bottom. The more of the mix it takes for the dot to disappear --- the lower the CYA.

My second test kit uses a slide with a dot on it. Again equal quantities of pool water and 0013 reagent ---- mix with the slide, wait, and begin raising the slide till it just becomes visable and read the scale at the water line Not the slide bracket at the top.

If your CYA really is high --- use double the pool water compared to the reagent then double the reading for better accuracy.

Hope you are reading incorrectly and don't have to drain any more.

[BarryY]

fcfrey, my test kit is a Taylor like the first one you described. I loose the black dot entirely with about 1/2" of water, about halfway to the 100 mark.

[waterbear]

fcfrey, my test kit is a Taylor like the first one you described. I loose the black dot entirely with about 1/2" of water, about halfway to the 100 mark.

The test is not accurate above about 80 or 90 ppm so I would suggest diluting a sample of your pool water with an equal amount of distilled water and testing that. Multiply the results by 2. If it is still testing high then dilute with 2 parts distilled water and multiply by 3. This should give you some idea just how high your CYA is

I would also stay away from the CYA reducers...they are melamine, exactly the same thing you are testing your CYA with. Do you want your entire pool to turn that milky white color and have to vacumn it out? Besides at $50 to $60 a gallon,which will lower about 10000 gal 20 ppm CYA (in actual use) it is a VERY EXPENSIVE solution!

Since you have a fiberglass pool you will have to do multiple drains and refills no more than a foot below your skimmer!....Do about 3 of them and retest. Keep at it until you get your CYA down to about 50 ppm and NEVER use stabilized chlorine for routine sanitation again and you won't have this problem.

[BarryY]

Well, after my SECOND drain & refill (about 90%), I'm down to cya levels of around 80-100. Going to try to maintain it from there.

What about my calcium hardness in a fiberglass pool? The mfg recommends around 300. Right now its around 150. Is there any danger in increasing it to around 300?

[waterbear]

Depends on where you ALK is. If both are high you run the risk of cloudy water or scaling if the pH goes high. The general consensus is that calcium is not needed in a fiberglass pool but I have been finding some conflicting info with no hard data to back it up one way or the other.....Fiberglass is more prone to staining by metals and perhaps the higher calcium levels help prevent this. Don't really know. Mbar might have some input on this subject. Maybe she will see this thread and reply.

[mbar]

I have heard coflicting points on this - first I heard that calcium is a metal and if there is too much in the water, it can stain the pool. Then I heard if there isn't enough calcium in the water, it will draw out metals from the fiberglass. They both sound strange to me. The first year I had stains, before I found this site, my pool had a calcium of 500, I had to drain 1/3 and refill 2 times to get it down. Then I have tried running my pool with no calcium, and I did have more stain than when I kept it at 150 the year before, but I was also playing around with my ph that year. To be on the safe side, I run the pool with calcium of 100 to 150. I think the most important thing in a fiberglass pool is to put sequesterant in the water. Just on Tuesday I had flood water flow into my pool and turn it green. I shocked it up to 30 (I went a little nuts with bleach), and put more sequesterant in it - I didn't get any stains. Also my ph tested at over 8 - but I remembered reading on this forum that high chlorine levels could make the ph test false. I thought it was strange with all the rain for the ph to go up, thank goodness for this site, I didn't add any acid. When I tested that night my ph was below 7, and my alk was 60. I added baking soda and borax, and my numbers were good today, and watter is crystal clear. So I think with the sequesterant, and low ph with the high chlorine kept my pool stain free. My opinion is to keep the calcium at bout 125 in a fiberglass pool.

[waterbear]

I keep my calcium about 200 or sligtly above but not for the fiberglass pool. I have a lot of grouted tilework on the outside of the spillover spa that gets constant water exposure and my spillover is made of marble so the calcium is for that.