CYA Levels

[JSBrackeen]

I bought a house last year with a pool, I fired my Pool Guy after a year as I was spending more money fixing the problems he created on top of paying him to keep the pool up.

So I have decided to take it over, I have the TF 100 Kit on order, should be here next week.

I had our local pool store, pretty good one local only not a big chain, test my water and my CYA is at least 100 right now. (Highest he said they could measure)

I know the only way to get it out is dilution, however, living in California right now and the city I live in require two things:

1. A permit to drain more than 10% of your pool.
2. I will get a $500 fine for filling my pool after letting the water out.

I was reading another website and they stated that CYA really just floats on the top of the pool to prevent the UV rays from getting to the chlorine. I thought the CYA actually bonded with the Chlorine and so it would be dispersed in the pool.

The reason I ask this, according to this other site, if you block off the main drain and just drain off 1-2" of water (I have enough yard I can hide that water run off) then fill the pool back up, the CYA should be greatly reduced.

Any logic to this?

Thanks for the help.

 

[RobbieH]

Hello and welcome to TFP!

In California, it is fairly easy to get a company to perform reverse osmosis on your pool.

CYA does not float on top. It's integrated into the pool water completely.

 

[jblizzle]

Welcome to TFP!!!

Well, the other website is wrong. CYA is evenly distributed through the water and you are correct that it bonds with the chlorine to protect it.

Sorry that is not going to work.

You can add water in the deep end and remove water from the top of the shallow end at the same time and replace water that way, but you will only lower the CYA by the % of water that you replace.

 

[timerguy]

That other site is WRONG!!! So, no, there's no logic in that. Until you get your own test kit and are able to do a diluted cya test you really have no idea what your cya truly is. In any case, you'll be draining more than 10 % Possibly MUCH more!

 

[JSBrackeen]

Thank you all, it sounded to good to be true.

My pool is in the complete sun about 8-12 hours a day so I have to add 4-6 inches of water per week.

I know it may take time, but as long as I don't keep adding CYA to my pool it should bring it down over time, correct?

I will just need to keep my FC levels higher until it comes down.

Also, what is the diluted CYA test? I have not gotten that far into reading yet.

 

[jblizzle]

Nope. CYA does not evaporate with the water. So when you refill, the CYA should end up at the same level as you started (just like salt would be left when the water evaporates). BTW, 4-6" is way more than normal evaporation I would think.

See the Extended Test Instructions for the diluted CYA test.

 

[JSBrackeen]

Thanks, I live in an area where it is very dry 10-15% humidity and gets up to 110 degrees, plus the sun is on my pool all day long. My pool can get above 90 degrees on a warm day and I do not have a heater. Plus, the way the pool is designed water splashes out quite a bit.

Thanks, for the CYA info, I will just need to drain slowing a little each week so that it does not run into the front yard and alert our "Water Police"

 

[timerguy]

Actually, evaporation will temporarily increase CYA level until you top off to a normal water level again.

 

[jblizzle]

According to this NOAA data: http://www.nws.noaa.gov/oh/hdsc/PMP_related_studies/TR34.pdf
At the Folsom Dam (closest place I could quickly find) the max evaporation rate is about 12" in July ... that would be 3" in a week. There is no way you are losing 4-6" of water per week to evaporation.

You might want to try a bucket test to see if you have a leak.

 

[JSBrackeen]

According to this NOAA data: http://www.nws.noaa.gov/oh/hdsc/PMP_related_studies/TR34.pdf
At the Folsom Dam (closest place I could quickly find) the max evaporation rate is about 12" in July ... that would be 3" in a week. There is no way you are losing 4-6" of water per week to evaporation.

You might want to try a bucket test to see if you have a leak.

Thanks, but that makes sense I did not say it was lost to evaporation only, that is a big part but also splashing it taking some out. The pool is 30 years old and the bricks they put around it cause us to loose a lot of water when the kids play in it. I can easily see it going down .5" after a crazy swim session with them, do that 4-5 times a week that is 2.5" and then add in 3" to evaporation, there is my 4-6" a week.

 

[Patrick_B]

Makes sense to me. I've been really surprised how much water kids can drag out of a pool. Constant in-out with 3-4 of them hitting the diving board, the loss is simply amazing to me.