High CYA in new Pool

May 18, 2015
23
Lafayette Hill, PA
Hello everyone. I bought a new house a few months ago and I just opened the pool last week. The pool is 25K gallons, plaster liner, DE filter, and inline chlorinator.

After opening I took a water sample to leslies. The FC was at 4 PPM, PH was at 7.4. The only alert was CYA being high at 100.

One week later I took another water sample to leslies. Same PH, same CYA, however FC dropped to .5 PPM. I bought a bucket of calcium hypochlorite shock and added a pound. I waited and tested myself today with a home kit and it looks like the FC is at about 2 PPM. Leslies said its normal to shock once a week. That seems like it would be overkill but this is all new to me so I am not sure.

I am reading about high CYA and how it can lead to chlroine lock. Is this something I should worry about? Is there anything out there to lower CYA without draining?

Also I believe I read those pucks (http://www.lesliespool.com/leslies-3-inch-jumbo-tabs-chlorine-buckets/3-inch-jumbo-tabs.htm?suggest=chlorine%2520puck) can increase CYA as well. Are there any pucks out there not made of the Trichloro-s-trianzinetrione that I can buy to maybe help the problem?

Any thoughts or ideas? Just a note the pool water looks crystal clear.

Moderator Note: This is two interrelated threads merged together. - tim5055
 
liquid chlorine

Hello everyone I just opened the pool on my new home (first time ever dealing with a pool). After doing so I took the water to be tested at leslies and it had 4 PPM FC however CYA is at 100%.

I have a chlorinator that takes the hockey pucks which I read can increase CYA. I believe I read using liquid chlorine will not increase CYA. I was thinking of continuing to use the pucks and just turning down the cholorinator and a combo of liquid chlorine. Does this make sense to help keep the CYA from going even higher?

Also what is a good brand/type of liquid chlorine out there? And how much would be needed per dosage in a 25K pool?
 
liquid chlorine

Welcome to the forum.
Many smarter than I will come along and give lots of great info.

At first glance your CYA is 100, not 100%. Which for a non SWG pool is very high. Should be less than half that. Likely all of that cya has been introduced via the pucks. Get rid of the pucks, remove/bypass the auto chlorinator and read the pool school article on the BBB methodology.

Secondly, pick up one of the recommended test kits and avoid the pool store at all costs unless they have a really good price on liquid chlorine, which can be used instead of bleach in the BBB method.

You will likely need to drain out 50% of your water to get your cya under control or you will eat thru copious amounts of bleach/LC to keep algae at bay.

First things first. Get a proper test kit and confirm your levels, especially that cya.


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Thanks @bobodaclown.... This forum has been great so far (I just found it today)...

One thing I noticed on leslies printout is that they recommend 1-4 PPM FC...I guess they don't take into account if your CYA is high. After doing some research today (and checking out your links) also I think I am going to stock up on some jugs of concentrated bleach and use that as an alternative to the hockey pucks. Over the summer I am hoping with splash out /backwashing the water level will drop enough where the CYA dips. I would rather not drain and refill already.
 
Re: liquid chlorine

bdex & Isaac have given you great information. The amount of chlorine you need to keep in the pool is a ratio based on your stabilizer level. The higher the stabilizer, the more chlorine. You can see the entire list HERE.

We will pretend that you are only at 100 CYA (I also think it is much higher) your minimum level of chlorine you should d keep is 7 ppm. To account for loss to the UV rays of the sun, people swimming, organics blowing into the water and the like you should target 12 so it never goes below 7. I don't know where Lafayette Hill is, you didn't list a state but if its in Florida, Texas, Arizona or any other sunny area bump that target up a point or two.

At this point I would recommend at least a 33% water exchange to get the CYA down. For vinyl lined pools leave at least one foot of water in the shallow end to keep from floating the liner and all pool owners are cautioned that in areas with a high water table lowering the water too much can “float” the pool out of the ground.

How much Pool School have you read? Start with these:
ABCs of Water Chemistry
Recommended Pool Chemicals
How to Chlorinate Your Pool
 
@tim5055 thanks for the info. I updated my profile I am in PA. It is not to sunny yet but there is a TON of pollen right now getting blown in.

Ok it sounds like I should try to swap some water out. The previous owner had a sump pump on the cover we would turn on after heavy rain so I guess my best bet is just dropping that in the pool and letting it drain some and then refilling correct?

And like the others said I should stop the pucks (for now at least) and just go straight liquid chlorine/bleach to not make the CYA problem any worse.

I also now know to not trust the people at leslies... The guy seemed like 100 CYA was totally fine and that shocking once a week will be ok.

- - - Updated - - -

Thanks... can you point me to one of the recommended test kits that those on this forum use?
 
@tim5055 thanks for the info. I updated my profile I am in PA. It is not to sunny yet but there is a TON of pollen right now getting blown in.

Ok it sounds like I should try to swap some water out. The previous owner had a sump pump on the cover we would turn on after heavy rain so I guess my best bet is just dropping that in the pool and letting it drain some and then refilling correct?

And like the others said I should stop the pucks (for now at least) and just go straight liquid chlorine/bleach to not make the CYA problem any worse.

I also now know to not trust the people at leslies... The guy seemed like 100 CYA was totally fine and that shocking once a week will be ok.

- - - Updated - - -

Thanks... can you point me to one of the recommended test kits that those on this forum use?
100 CYA and shocking one a week is great for Leslie's - it continues their sales. Not so good for your pool.

I understand the pollen, it is finally slowing down here in SC.

Yes, no more pucks or any kind of solid chlorine like little bags of granular shock.

Where will you get your fill water from and are there any possible issues that you know of like wells may have iron.
 

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When I opened the pool a couple weeks ago it was a little low maybe an inch below the tile. I just dropped the hose in then to fill it. We have public water here so no well. I guess I am surprised the cya is still so high after the previous owner did drain it some last year before closing. It sounded like he just did whatever Leslie's told him to since he got the pool installed 4 years ago. I think he has just been using pucks and shocking once a week like they said he should letting the cya keep going up.

How are places like Leslie's allowed to do this to people?
 
The link for the TF-100 test kit is in my signature,

I have a better question for you, Why do people blindly take the advice of pool stores who make their money by selling as many chemicals as they can?
 
Hi, first post. Just spent last hour reading many posts on CYA. This looks like a good place to jump in.

I drained my pool last year mid June. Got CYA down to 30-50 (I got 30, Leslies got 45 & 50). Tested for FC, pH, Hardness, & alkalinity every couple of weeks with Taylor kit. Tested every couple of day for TC with an old OTO tester. Numbers always looked good (e.g. pH 7.4-7.6; hardness 200-250, alkalinity 50-80, FC usually 4-6, occasionally dropped to 2) and algae under control. Last test was late October, FC 3.5, pH 7.4, alkalinty 75, and hardness 275.

First test this spring was mid April (maybe a little late) FC 4.5 pH 7.2, alkalinity 40, harness 290. Algae being resistant, so I shocked with cal hypo to get to 10 ppm. Week later, FC at 13 and stayed high, got down to 5 a week later, but algae still a problem. Tested for CYA, it was off the charts. Took water to Leslie's (I'm out of CYA tester; yes I've ordered more) and they got 70. I knew that was not right. Took sample back a week later they said CYA was 120. I tested today (ok, i had a about 5 ml of solution, so I doctored up a test with 1:2 dilution and got about 100, so that is 200.

People at Leslie's said I had CYSA buildup in my pipes and when I refilled my pool it all leached back into the water. Has anyone heard of this? Anyway, that convinced me not to drain again but they sold me Bio active to reduce CYA. I put it in today, but my Cl is higher than it is supposed to be.

I think I need to drain again, but if I have build up of CYA in my pipes, I'll be right back in the same place. Has anyone had this problem after draining their pool. Back to over 200 CYA in less than a year?

Yes I am now convinced that trichlor tabs are an evil plot. I'm going to figure out how to use bleach from Sams.

Thanks for any insight.
 
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