CYN too high

Jun 26, 2014
9
Natalia
I am a new pool owner, pool was put in Aug 2012 end of month.
Fiberglass IG 14x32
cartridge filter ( cleaned every sunday)

I have not had any problems until this pass month. My CYN is over 100 and I am showing NO chlorine in pool. So that has caused me to have some areas of small spots of algae. (pool is crystal clear)
I went to pool store and they told me too drain about a ft of water then refill with fresh water. I did this yesterday. Still showing no chlorine... Oh I use 3" tablets in a floater.
I am so frustrated not knowing what else to do... also I want to know that while I am trying to lower this CYN should I still have the tablets floating in the pool??

It all started with having the yellow algae due to a lot of rain ( before all this chlorine was fine) So the pool store told me to get ph level adjusted, then put this yellow out in pool to kill algae, then shock the pool.. Then next morning my pool was bright green , so they told me to shock a second time. Well it cleared the algae but now I am battling this CYN level and no chlorine UGGGG.
 
Welcome to TFP, You've found an excellent forum with loads of helpful people. Many of which are experts in water chemistry.

http://www.troublefreepool.com/content/123-abc-of-pool-water-chemistry

Check out that link. The tabs that you are using add Chlorine and CYA....CYA doesn't go away unless you drain water off. Due to this most here either use liquid chlorine/bleach to chlorinate their pool or use a SWG.

What kind of test kit are you using to test your water?

If you want to adopt the methods that the majority of users on this forum use, I'd strongly suggest you start buying bleach, and read everything in the "Pool School" tab. If you don't have a good test kit (see "recommended test kits" in pool school). I'd strongly suggest you get one of those. The TF100 would be your best value overall.

If you're wondering, once your pool is clean again you won't use much bleach daily, but during the "SLAM" process you will add quite a bit.

Based on the experiences of thousands of users who have been exactly where you are, I can without a doubt say there are no magic potions. The best way to eliminate the issues you are seeing is to stop visiting the pool store, and start taking care of your pool the most efficient way.

To answer the questions you have proposed. Do you have a full set of test results? If so please post those and notate what kind of test kit was used or if they are pool store results.
 
Welcome to TFP!

Getting the CYA level down should be your first priority. You need to lower CYA to around 50 or 60, which will likely take several rounds of water replacement. Once you have done that you will need to SLAM the pool to get rid of the algae.

You may also want to think about stopping using the tricolor tablets. They constantly add CYA, which is how you got into this situation.
 
Speaking from personal experience in the identical situation ...unfortunately the only solution is to dump water (lots of water) to lower the CYN to an acceptable level. I'd suggest dumping about 3/4 of your entire volume of water; i know that's sounds like a drastic step but it will do the trick. From that point forward be very liberal with weekly backwashing of your sand filter, or simply removing 2"-4" of pool water on a regular basis and replacing with fresh water. You should never have the CYN buildup this high again and should always have a good strong chlorine reading.
 
I did a 100 percent drain and fill a few months ago. 16,000 gallons only cost me about 150 dollars. Check your water and sewer rates. I then raised my CYA to 60ppm immediately.

The problem is you don't know how high above 100 your CYA is. Why drain half to only find out your levels are still too high?
 
Test where done at pool supply
FAC 0
TAC 0
CA 190
CYA they put 300
TA 60

I don't know what to do I am in a panic ... pool turning cloudy by the minute and green dusk appearing !! I know I sound dumb but what do I do . I replaced 1-2 ft of water yesterday . I am not at all good at chemistry and using simple kit for chlorine and ph. I have a fiberglass pool how much can I drain at a time and do I remove the tablets???
 
Thats what the pool company put, but I went to another location (same co) and she said they can't read past 100 she doesn't understand why they put 300. Do I take the chlorine tablets out while Im doing this or leave them in. I think this happen because they had me shock 3 times with a shock that has stabilizer in it and combination with my tablets. Im sorry i sound a little dumb, I just have a hard time with this kind of stuff. My first 2 years with this pool I had no problems and never had to shock. Pool is in full sun most of the day. The tf100 is the best? I will not have trouble understanding it or is it user friendly.
 
The pool store and trichlor got you in to this mess. Do not rely on them for test results, especially with CYA. You absolutely have to get yourself a good test kit. If I were you I would order a test kit. Then while you're waiting for it to arrive, you can start partial drains and refills to lower your CYA. Then when your test kit arrives you can mount a proper attack. Right now, I don't think you (or the pool store) has any real idea of your CYA level, so you really can't SLAM effectively, especially if it is at 300 like the pool store says. That's how I'd approach it if it were my pool. rder your kit, start draining and refilling til your kit arrives.

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Get rid of the tablets. That's what caused your issue in the first place. You said you had no problems the first 2 years. But the 2 years of tablet use have built your CYA up to an unmanageable level. Yes, the TF-100 is the best value, and easy to use. If you want people to tell you what to do, then I'll start. Get the TF-100.

Thats what the pool company put, but I went to another location (same co) and she said they can't read past 100 she doesn't understand why they put 300. Do I take the chlorine tablets out while Im doing this or leave them in. I think this happen because they had me shock 3 times with a shock that has stabilizer in it and combination with my tablets. Im sorry i sound a little dumb, I just have a hard time with this kind of stuff. My first 2 years with this pool I had no problems and never had to shock. Pool is in full sun most of the day. The tf100 is the best? I will not have trouble understanding it or is it user friendly.
 
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srenee, I am in the same boat as you. Pool stores were telling me to add their cholorine and tabs (all with stabilizer), never mentioning that my CYA was going up. Two store readings said CYA was 100. I bought my own kit and readings were over 200. I drained my 15K gal pool first time maybe 5K gals. Reading was 180. I drained another 10K this past weekend. My reading is now 80. Even though that is high, I'm working to get cholorine levels where they need to be (guys here will help you when you are ready for that). Then I will refill 50% again later. My pool was also clear...but there are lots of germs and contaminants in there that you cannot see. I would just go ahead and drain all but a foot of water with CYA that high. Otherwise, it'll take longer. Just my opinion.
Good Luck! This does work!
 
I am draining right now, my pool is approx 16,000 gal Only did 1-2 ft last drain may need to do more, just wondering if you can drain a fiberglass pool a lot or only and few feet at a time? Been told you can and cannot ... just trying to figure what is the right answer


srenee, I am in the same boat as you. Pool stores were telling me to add their cholorine and tabs (all with stabilizer), never mentioning that my CYA was going up. Two store readings said CYA was 100. I bought my own kit and readings were over 200. I drained my 15K gal pool first time maybe 5K gals. Reading was 180. I drained another 10K this past weekend. My reading is now 80. Even though that is high, I'm working to get cholorine levels where they need to be (guys here will help you when you are ready for that). Then I will refill 50% again later. My pool was also clear...but there are lots of germs and contaminants in there that you cannot see. I would just go ahead and drain all but a foot of water with CYA that high. Otherwise, it'll take longer. Just my opinion.
Good Luck! This does work!
 
You can probably drain 50% safely, but it depends on your water table. Someone with more knowledge of fiberglass inground pools will chime in soon I'm sure. Regardless, start draining, and stick with a 2 foot drain for now.

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How are you draining? Gravity flow through a hose? Drain through filter? Sump pump?
 

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