New Member / New Pool Owner - CYA and CH really high!

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petemoney

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Jun 25, 2013
9
Phoenix, AZ
Hi everyone,

New to the forum... bought a home here in Phoenix in November (my first pool ever - no knowledge of pool care...) and the pool water was really clear at the time, so all I did was add a chlorine tablet (neighbor's advice) once a week over the winter and kept the leaves out. That kept the pool water clear... until temperature started getting into the 90s consistently, then I had a yellow algae bloom! Called the local pool guy and he said to add 6 bags of shock, which seemed to make the yellow/brown clouds on the sides/bottom of the pool go away (hooray!). Water temp was in the low- to mid-70s at the time. About a month ago, looked like I had some yellow algae coming back, not as bad as first time, but didn't want it to get that bad again... so I called the local pool guy and he said it might be good to add some copper algaecide and throw in a bunch of shock again (in the reverse order). That cleared up the problem again, and for the last month the water has been clear. Now I'm doing maintenance dosage on algaecide 1x/week (although switched away from copper over to InTheSwim's Algaecide 60). Local pool guy also said I needed to keep more chlorine tablets in the floating dispenser, so now I have 4 tablets at a time in the floater, adding on average 1 more per day to keep 4 in there at a time. My kids swim every day for at least an hour or two during the summer. I've also been adding 1 bag of Aqua-Chem (from Costco) shock every 2-3 days to keep some chlorine in the pool... it seems to burn right through the chlorine. In trying to figure out why it's burning through so much chlorine, I started to research pool chemistry and came across the forum a couple weeks ago... so ordered my test kit and got my results last night:

FC = 1ppm
CC = 1ppm
pH = 7.2
TA = 180
CH = >820 (I put in 82 drops and the test tube still hadn't turned blue... my back was getting tired, so I gave up at 820... realizing this was probably off the charts on the high end and would require fixing anyhow...)
CYA = >100 (the black dot disappeared well below the 100 line on the test tube... if I had to guess, I'd say 140-150 based on the intervals between 80-90-100 further up the tube)

I shocked the pool (w bag of shock from Costco) on Sunday, and did the maintenance dosage (2 oz) of Algaecide 60 on Saturday. Test results are from Monday night (last night). I've also had to add some soda ash over the past month to keep pH up to 7.2, it has dropped to 7.0 a couple of times lately. TA is very high at 180... I added a little bit of muriatic acid to lower it about a week ago, but didn't seem to help for more than a couple of days.

With CH and CYA levels as high as they are, I'm guessing I need to drain the pool and start fresh? Like I said, I bought the house in November, and not sure when the water was last replaced...

Help?

Thanks in advance!
-Pete
 
Yes, the only way to lower CYA/CH is by draining the pool. They recommend doing partial drains here.

Start reading Pool School (button in the top right corner), and read the forums - I've learned so much by reading the threads here. You don't need and shouldn't use aglaecides - they can add unnecessary and unwanted chemicals to your water. As long as you keep your chlorine levels up, that will keep the algae in check. People here use regular household bleach for both chlorination and shocking. It's very effective and cost efficient. Don't use pucks. Those add calcium or CYA to your pool, eventually causing it to become out of whack, as you've experienced. The more CYA you add, the more chlorine you need. That's why you're burning through chlorine so fast.

Since owning my pool, I've only used bleach for chlorination, with some occasional acid, and my pool has been crystal clear from day one. I test regularly.
 
Adding those bags of shock will continue to add to your CYA problem too.

Dilute your pool water by 1/2 before doing your CYA measurement, then double your result to see a little better where you are.
 
Thanks for the responses! I have a bunch of chemicals still (bought some in bulk at Costco... learning that was a bad idea), but thinking maybe I'll burn through the rest of those and they may get me through to the end of summer... then drain/refill at that time and make the switch to the BBB method after summer swimming is done. Would I be creating any problems if I do that? Not sure I have a couple of days to drain/refill the pool during summer with the kids swimming every day. Also hate to throw away a bunch of pool chemicals unused... but if I'm creating problems by doing this that won't be taken care of with a drain/refill after summer, then I'll just make the kids go without the pool for a couple of days (I can hear the whining now...).

What do you think?
 
:wave: Welcome to TFP!!! :wave:

You are going to have a crappy summer if you do not take care of the CYA issue now ... better to lose a couple days swimming now to allow for the drain and refill than to lose weeks later WHEN your pool turns green.

The chemicals (solid chlorine) you have will last for years and once you get the CYA under control you can use them for vacations or bumping the CYA when you need it. Trying to "save money" by making your problem worse is ultimately NOT going to save you any money and likely cost you a lot of swim time.

Recheck the CYA using the diluted method to find out how high it really is. FYI, if you CYA is around 150ppm (likely higher), you would need to keep the FC > 11ppm at ALL times in order to hope to prevent algae from starting. Your pool is currently a ticking time bomb if it has not turned green already.
 
Thanks, Jason.

Diluted method = mix 1/2 pool water + 1/2 tap water, then do the CYA test and double the result?

I think we'll begin the drain/refill process asap... looks like the pool calculator says I'll need to drain around 2/3 of the pool.
 
That is correct for the diluted method.

It may seem like a lot of work now ... but seriously I think you would be heading for a disaster by not getting the CYA in check.
 
Ok, so using the diluted test method, it turns out my CYA level was 220!!!. I plugged in my numbers to the Pool Calc and it said to replace 77% of the water. So last night I drained about 75-80% of the water. This morning I have a hose starting the refill process. I'm anticipating the following steps once the pool is full and I can run the pump again:
1. Test water w TF-100 kit, then if CYA level is around 50 as I'm hoping, will likely need to do the following:
2. Balance pH (using either baking soda or muriatic acid to raise/lower)
3. Add liquid bleach to bring FC level up
4. Possible adjustment for TA level (it was 180 prior to drain/refill)

My question is, given that I had yellow algae recently, once my CYA level is around 50, do I need to bring FC up to Target level or Shock level?
 
It wouldn't hurt to bring it up to shock level and do and overnight chlorine loss test. If it loses less than 1 ppm chlorine, has less than .5 cc and looks clear then let the FC drop to target level and swim. If it doesn't meet those criteria then continue the shock process until it does.
 

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After a couple of drain/refills, finally got my CYA lowered.

Last night I tested it again, and the CYA is down between 40-50 (perfect!). So in the evening just after the sun went down, I dumped in what I thought would be enough liquid bleach to bring it up to shock level. Tested about 2 hours later before going to bed, and the FC was at 25ppm. I thought this would be high enough to kill off whatever algae was in the pool... apparently not! This morning before the sun came up, I tested again and FC was only 18ppm. I'm guessing that I need to raise FC level even higher??? Or am I missing something? 25ppm was even higher than the Chlorine/CYA chart indicates for my CYA level of approx 45 (even with CYA of 50, FC for shock is only 20...). Not sure how algae could have survived my FC at 25ppm???
 
The fact that the FC drops shows that it was killing something off. This proves there is something in the water.

You need to maintain the shock FC level consistently to ensure that all the algae is eradicated following the Shocking Your Pool PROCESS. This is not the same as the pool stores recommend by adding a TON of chlorine once and hoping to kill everything off without damaging your pool and equipment. The process works if you follow it.

You should NOT have blindly adding FC up to 25+ppm when you should have known that the shock level was only 20ppm.
 
petemoney said:
After a couple of drain/refills, finally got my CYA lowered.

Last night I tested it again, and the CYA is down between 40-50 (perfect!). So in the evening just after the sun went down, I dumped in what I thought would be enough liquid bleach to bring it up to shock level. Tested about 2 hours later before going to bed, and the FC was at 25ppm. I thought this would be high enough to kill off whatever algae was in the pool... apparently not! This morning before the sun came up, I tested again and FC was only 18ppm. I'm guessing that I need to raise FC level even higher??? Or am I missing something? 25ppm was even higher than the Chlorine/CYA chart indicates for my CYA level of approx 45 (even with CYA of 50, FC for shock is only 20...). Not sure how algae could have survived my FC at 25ppm???
Click to expand...
It can take several days. You raise it to shock level, retest and raise FC again every few hours, again and again until you meet the three criteria that say you're done. Hint: they're in The Shock Process. Note it is a process. Many steps. Not a one-time mega-dose of some miraculous shock powder the pool store will foist on you.


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Got it - I need to keep FC at that level for the duration of the process. Thanks for your patience... I'm new at this.

Thought I had seen a post somewhere in the site (can't find it right now), about yellow algae having a higher FC shock level... is there another Chlorine/CYA chart for yellow algae?
 
petemoney said:
Got it - I need to keep FC at that level for the duration of the process. Thanks for your patience... I'm new at this.

Thought I had seen a post somewhere in the site (can't find it right now), about yellow algae having a higher FC shock level... is there another Chlorine/CYA chart for yellow algae?
Click to expand...
It's in the pool calculator. But first you get rid of the green stuff. Most of the time, that's the end of it, you don't need to go up to mustard shock level.
 
petemoney said:
Ok, so using the diluted test method, it turns out my CYA level was 220!!!. I plugged in my numbers to the Pool Calc and it said to replace 77% of the water. So last night I drained about 75-80% of the water. This morning I have a hose starting the refill process. I'm anticipating the following steps once the pool is full and I can run the pump again:
1. Test water w TF-100 kit, then if CYA level is around 50 as I'm hoping, will likely need to do the following:
2. Balance pH (using either baking soda or muriatic acid to raise/lower)
3. Add liquid bleach to bring FC level up
4. Possible adjustment for TA level (it was 180 prior to drain/refill)

My question is, given that I had yellow algae recently, once my CYA level is around 50, do I need to bring FC up to Target level or Shock level?
Click to expand...

:goodjob:

You sir are going to have a successful summer.
 
Last night, I took the FC up to 25ppm, then tested at 5am this morning and it was down to 18ppm. I was out of bleach though, so couldn't get back up to shock level until tonight. Just re-performed the CYA test and believe it's between 45-50, so I'm going with 50. As we have had mustard algae over the course of the past couple of months, I'm taking it up to mustard shock level tonight. Will re-test FC in the morning and add more bleach if needed. The water is (and has been) clear. Although when I sweep, there are brown/orange clouds coming off the sides and bottom (smaller than previously, but still there... at least they are not big enough to cloud up the pool), so I believe the mustard algae is still present. As Jason indicated, the algae ate up a lot of chlorine overnight last night (from 25 -> 18). CC is 0.5ppm, so that seems ok. Just need it to keep it at a high enough FC level for long enough to finish off this punk algae.

Let me know if it seems like I'm missing something! Thanks again for the help!

Pete
 
Ok - two nights ago took FC up to 29 (mustard shock level... after re-reading the mustard algae shock article, I realize I only needed to go to 20ppm...) and made sure it stayed above 20 (normal shock level for CYA 50) all day and overnight for a couple of days. Tried to keep it above 20 each time I reloaded it with bleach, because I was gone at work all day and wouldn't have chance to test or add more during the day. Anyhow, took it up to 29 last night, retested this morning and it passed the OCLT this morning, staying at exact same level overnight (woohoo!). Which should mean my algae is gone.

Before swimming in it, the FC needs to be below shock level, correct? That would be normal shock level (20ppm), not mustard shock level (29ppm), right?

Thanks for all the help! I know I sort of stumbled through the process, but it looks like it worked.

Pete
 

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