Dealing with scale problem

[beaverplt]

Hi, Yes I did mean CYA. Wish I would have read this before I tested CYA again this morning. OOPs. Anyway, Now that I seem to have my chlorine, PH, TA, and hardness in line, I need to attack my algae problem. My problem is severe. All, and I mean all of the liner is covered with green, black and a yellowish green algae. It does not come off unless vigorously scrubbed. I've been running my pool cleaner as much as possible with barely any headway made. In the past if I've had issues, I've used fairly inexpensive algae guards, mostly HTH, with good results. Now after reading things on the forum along with comments on this thread, I don't want to go headlong into buying anything. Any suggestions?
BTW, thanks so much for the input thus far.

[Watermom]

Your chlorine cannot "be inline" if you are fighting algae. (I'm not sure what level that means.) The way to kill algae is to shock your pool (based on your CYA level) and hold it at that high level until it is dead. Brush the pool frequently when the chlorine is high and run your pump 24/7, cleaning your filter as needed. Take a look at the Best Guess Chlorine Chart in my signature below. It shows the correlation between CYA levels and needed chlorine levels.

[beaverplt]

Hi Watermom. I'm assuming that stabilizer levels in the chart and CYA are the same thing? My test kit gives me a chlorine level over 5 ppm. My CYA is probably still low as I only added stabilizer on Saturday. Does that mean my "free chlorine" is low and therefore my chlorine is ineffective?

[PoolDoc]

stabilizer = "conditioner" (mostly in Calif) = cyanuric acid = isocyanuric acid = CYA = "CA" (some kit instructions => C.A., cyanuric acid) = etc.

Why have just one name for a chemical, when you can have a half dozen?

[Watermom]

Did you look at the Best Guess Chlorine Chart in my signature above to understand the CYA (stabilizer) and chlorine connection?

Your kit only has the capacity to measure to a chlorine reading of 5ppm which means you can't really tell what your chlorine is when it reads 5ppm. This is one of the main reasons we want people to order the K2006 as it can measure chlorine levels way higher than that.

Assuming that your CYA is still low since it was just recently added, you need to get your chlorine level up to around 10-12 and try and hold it there in order to kill the algae. Since your kit won't read higher than 5, you kind of just have to judge based on the color. Take a look at the first post in the following thread. If you click on the link in that first post, it will give you a color matching to try and decipher what various OTO colors mean in terms of chlorine levels. (Your kit uses an OTO chlorine test.) Aim to keep yours in the very dark yellow/orange level.

http://www.poolforum.com/pf2/showthr...sults-by-color

[beaverplt]

Hi again, Yes, I did look over the chlorine chart, and it makes sense. I'm not sure I understand the difference between the two "shock" columns. Looks like I need to get out to buy some more shock. Did I read in another forum that some people use regular unscented chlorine bleach instead of paying for shock? I'm assuming you need to use more due to the smaller amt of active ingredients.
One question I have is about CYA levels is the relationship between CYA levels, total chlorine levels and free chlorine levels. When CYA levels are closer to "normal" is there less of a spread between total and free chlorine levels?
Also, how long does stabilizer levels take to rise after addition to the pool?

P.S. one more name for stabilizer - clarifier.

[Watermom]

Stabilizer is NOT the same thing as a clarifier. Clarifiers cause smaller particles to clump together so they can be filtered out more easily, however, we seldom suggest using them. Stabilizer, or CYA, is kind of like sunscreen for your chlorine. Without enough in the water, your chlorine is quickly lost to the sun.

Regarding the two shock columns, you typically only need to shock as high as the first column unless you have a really resistant algae like maybe mustard algae. However, if you keep your chlorine at the proper levels, you never have to shock. Some pool stores will tell you that you need to shock weekly. That is not true. The only time you ever need to shock is if your chlorine levels drop too low or if you have a lot of organic debris in the pool. I seldom shock. I test my water almost daily and always maintain proper chemistry. When you do need to shock, you can just use bleach. We like to say that the word "shock" is a verb and not a pool product. You would just add a larger than normal dose of bleach to get to the shock level that you need based on the Best Guess chart. Make sense?

FC + CC = TC. Always. Regardless of what your CYA levels are, the equation is always constant. Ideally, you want your CC to be zero which means that your free chlorine and your total chlorine would be the same.

We may have already told you this but not sure. But, in your 25K gallon pool, each 121 oz. jug of 8.25% bleach will add about 3ppm of chlorine to your pool. Use that as a reference to help you figure out doses of bleach that you need to add to your pool.

Hope this is all helping you better understand taking care of your pool chemistry.

[PoolDoc]

Where have you seen stabilizer called "clarifier" -- if someone in a pool store is calling it that, I'm pretty sure they are just confused.

The relationship between CYA and chlorine is more a constant fraction, rather than a constant PPM. That is, under ideal circumstances, if your chlorine ppm is 5% of your CYA ppm, everything's good. On the other end, sometimes killing mustard algae takes a chlorine ppm that's 25% or more of your CYA level. The relationships are not all mathematically linear, so that's not perfectly true. For example, a chlorine level of zero is not going to help, even if your CYA is zero.

But, it's approximately true.

Finally -- your pool doesn't care how the chlorine gets there: chlorine gas, bleach (sodium hypochlorite), dichlor (sodium dichloro-isocyanuriate) all work. But if you use store bleach, get the PLAIN store brand 8% bleach, and not the 'flavored' bleach that Clorox has been marketing.