Hello, My name is Suk. My house has a pool since the date I bought it in 1995. Just started to learn how to take care the pool myself beginning of last year. And, I am currently puzzled by yellow algae all over the bottom of the pool and high CYA (~170). What should I do? I am able to start thinking about filling the pool as it takes so much of time and money to maintain it... But, my kids love it ... So, that's the reason I am here.
Hi, newbie frustrated with algae and high CYA
- Thread starter suk111
- Start date
Hi welcome to TFP 
If you want to stick around and learn to test and balance you're own water, pool care will be a breeze and not drain your wallet.
First thing is get a good test kit: Pool School - Test Kits Compared
While you are waiting for a good test kit, start reading in pool school:
Pool School - ABCs of Pool Water Chemistry
Pool School - SLAM - Shock Level And Maintain
If you want to stick around and learn to test and balance you're own water, pool care will be a breeze and not drain your wallet.
First thing is get a good test kit: Pool School - Test Kits Compared
While you are waiting for a good test kit, start reading in pool school:
Pool School - ABCs of Pool Water Chemistry
Pool School - SLAM - Shock Level And Maintain
You will need to drain a good percentage of the water to get the CYA to a manageable level. Are you under any water restrictions at this time?
I had been told by Taylor's support personnel that I had to drain at least 1/3 of the water and refill with fresh water.
I am a little hesitate to do so.... and I haven't checked with the water company whether there is any water restriction yet. The more I read and more I am confused as there are different opinions about whether is such a thing called
"chlorine lock" and whether high CYA and high chlorine is indeed not good, etc.
I had already started using the Taylor K2006 test kit and skimmer sock these few days to try to keep the FC to above
25, trying to shock out the algae. It seems to be working but slowwwwwwly..... and the R871 bottle is quickly
used up.
I am a little hesitate to do so.... and I haven't checked with the water company whether there is any water restriction yet. The more I read and more I am confused as there are different opinions about whether is such a thing called
"chlorine lock" and whether high CYA and high chlorine is indeed not good, etc.
I had already started using the Taylor K2006 test kit and skimmer sock these few days to try to keep the FC to above
25, trying to shock out the algae. It seems to be working but slowwwwwwly..... and the R871 bottle is quickly
used up.
Hi there
There really isn't such a thing as "chlorine lock". The amount of chlorine you need in your pool to keep it sanitary is dependent upon the amount of CYA in the pool. You can have CYA that high and maintain a super high chlorine number and be ok.....it isn't locked it is impractical.
Another link I didn't add is this one:
Pool School - Chlorine / CYA Chart
So, yes. Draining to reduce your cya is a good course of action. How are you chlorinating your pool?
There really isn't such a thing as "chlorine lock". The amount of chlorine you need in your pool to keep it sanitary is dependent upon the amount of CYA in the pool. You can have CYA that high and maintain a super high chlorine number and be ok.....it isn't locked it is impractical.
Another link I didn't add is this one:
Pool School - Chlorine / CYA Chart
So, yes. Draining to reduce your cya is a good course of action. How are you chlorinating your pool?
With CYA in the 150+ range "shocking" the algae out is not going to work. And, the comment to drain 1/3 of the pool is rubbish. It's simple math. As the CYA is mixed into all the water you need to figure our where you want to be. If you are truly at 170 (CYA tests above 100 are just a guess, not very specific contrary to what anyone says) and want to get to 40 then you need to replace 76% of the water (PoolMath does these type calculations for you).
Read through the links Aimee posted.
Read through the links Aimee posted.
Well, there are other opinions and then the facts based on science that we teach here. You have to choose who you are going to try to learn from.
Your CYA is way too high and you need to replace at least 50%
That FC of 25ppm is not nearly high enough for the SLAM process with your current CYA.
Your CYA is way too high and you need to replace at least 50%
That FC of 25ppm is not nearly high enough for the SLAM process with your current CYA.
Not even half way there. Shock level for 170 CYA would be 68 (40% of CYA)
suk111,
I do hope you take the time to read the links I posted. Information that is based on science, not opinions.
I'm concerned when you say "shocking out"........if you are adding a powdered chlorine, it most likely contains even more CYA.
Any chlorine in dry form is stabilized by something else. Most commonly calcium (calcium hypochlorite) or CYA (dichlor and Trichlor). Liquid chlorine doesn't add anything but the chlorine, water and small about of salt in the bottle. And bleach (plain unscented) is liquid chlorine, just a lower concentration than what the pool store sells.
We are happy to help you but it starts with basic understanding of what you are adding to your pool and why.
I do hope you take the time to read the links I posted. Information that is based on science, not opinions.
I'm concerned when you say "shocking out"........if you are adding a powdered chlorine, it most likely contains even more CYA.
Any chlorine in dry form is stabilized by something else. Most commonly calcium (calcium hypochlorite) or CYA (dichlor and Trichlor). Liquid chlorine doesn't add anything but the chlorine, water and small about of salt in the bottle. And bleach (plain unscented) is liquid chlorine, just a lower concentration than what the pool store sells.
We are happy to help you but it starts with basic understanding of what you are adding to your pool and why.
The current CYA reading is definitely beyond 100.
The test solution takes 1/3 the distance between the bottom of the tube to the 100 mark
when the dark dot at the bottom disappears. Is that 170?
I used to use calicum hypochlorite and it just went out.
Now, I am using HDX liquid chlorine from Home Depot.
OK. I will keep reading.....
The test solution takes 1/3 the distance between the bottom of the tube to the 100 mark
when the dark dot at the bottom disappears. Is that 170?
I used to use calicum hypochlorite and it just went out.
Now, I am using HDX liquid chlorine from Home Depot.
OK. I will keep reading.....
And, the cartridge filter doesn't have backwash.
How do I drain the pool?
Need to buy a pump, right?
And, is it safe to drain so much water at one time for a gunite pool?
Also, where should the water go?
There are a few deck pot drains near the pool but they are kind of clogged.
How do I drain the pool?
Need to buy a pump, right?
And, is it safe to drain so much water at one time for a gunite pool?
Also, where should the water go?
There are a few deck pot drains near the pool but they are kind of clogged.
You can do a diluted test with tap water for your home CYA test but really........clearly you need to drain a good bit of water. If you were using calcium hypochlorite to chlorinate, that wouldn't have contributed to this troublesome high CYA. But it would have added a lot of calcium.
Your CYA is so high that your minimum FC is kind of outrageous. The target, minimum and shock levels are all calculated as a percent of CYA. We don't really know exactly how high yours is because over 100, the margin of error increases. But let's pretend it is 170. Your minimum FC should be about 13 just to make the water safe. Shock level is sky high as mentioned above. If you want a detailed explanation check here. Chlorine/CYA Chart
I don't think you will really get ahead of algae without draining to reduce that CYA
Your CYA is so high that your minimum FC is kind of outrageous. The target, minimum and shock levels are all calculated as a percent of CYA. We don't really know exactly how high yours is because over 100, the margin of error increases. But let's pretend it is 170. Your minimum FC should be about 13 just to make the water safe. Shock level is sky high as mentioned above. If you want a detailed explanation check here. Chlorine/CYA Chart
I don't think you will really get ahead of algae without draining to reduce that CYA
Don't equate “just a little over" or “just a little under" to a number, the tube is not marked for such extrapolation.
So, 100 is the limit of the CYA test, so you have to do a diluted test. While the full instructions are in the Pool School, here is the short version. Mix 50% pool water with 50% tap water. Use this mixed sample as your test water. If still at a 100 you will need to dilute more. Here is a great chart by JamesW to explain dilution rates and what you multiply the results by to get an approximation of your CYA level.
Pool water......Tap or distilled water.........Multiply result by
....1...................1................................2
....1...................2................................3
....1...................4................................5
The problem is that when doing a diluted test not only do you multiply the rage of the test you multiply the error rate of the test, so results are a ballpark - not an absolute.
Forgot to mention that I also used 3" Chlorine tabs (Trichloro-s-trianzinetrione) for the past 12 months.
That probably is the cause for this high CYA.
I took off the floater 4 days ago after I learnt that it contains CYA.
Read the chart and understood the number....
So.... drain the water... need to search how...
That probably is the cause for this high CYA.
I took off the floater 4 days ago after I learnt that it contains CYA.
Read the chart and understood the number....
So.... drain the water... need to search how...
I'm not one who can help with the draining with a cartridge filter question. I'm not familiar with them as all.