Looking for some help....waving the white flag in regards to Cl

May 6, 2014
14
redding, ca
Hello everyone.

I’m pretty new to this pool stuff, bought a house in November with a 13600 gal fiberglass pool. It is setup with a Pentair pump and filter system. Throughout the winter the pool was easy to maintain. Kept my eye on Cl and Ph and augmented as necessary. With the weather warming up I’m having some issues an am very frustrated, looking for some help.

Last week I noticed that I could not maintain chlorine in the pool. The previous owners and myself had been using the trichlor tablets, and augmenting with liquid chlorine as needed. Weather just starting to warm up here, and no matter what I did I could not hold chlorine. No evidence of algae at all, pool crystal clear. I finally broke down and went to the pool store to get a water test. 0 FC and TC, CH @ 150, CYA @ 50, TA @ 80, PH @ 7.4, 0 copper/Iron.

Pool store # 1 said I should add 15lbs of CH, and add 2 lbs of 73% Ca Hypo to shock the pool. Over the next 2 days I did as instructed. But chlorine continues to disappear rapidly. In addition, my water is somewhat cloudy, and the first couple days some brown dusty looking particles would be present in the bottom of the pool. I would manually vacuum these up (sometimes twice a day) and then proceed to manually clean the filters as so particles wouldn’t get washed back into the pool. I called the pool store and they said sometimes the cloudiness/particles are normal when adding CH and Ca Hypo and to continue to vaccum. The cloudiness is slowly improving, but the ability to hold chlorine is not. The shock pretty much burned up in 24hrs or less.

After starting in on some research I found your site. I purchased a TFT CYA and HAS/DPD chlorine test to go along with the Alk/Cl/Ph test I already had. While waiting for the tests to arrive I continually was adding liquid 10% chlorine to try and maintain Cl levels, but felt as if I was spinning my wheels. Decent levels (10-15ppm) in the morning, 0 chlorine by the evening..I also removed all the trichlor tabs.

Test arrived yesterday afternoon. I decided to perform an OCLT and the CYA test. I added an entire gallon of 10% chlorine at dark, ran the pump for an hour and than ran the two tests. CYA 70-80, and FC 9.5, CC .5.

Up at 6am, prior to the sun on the water and tested the Cl levels again. FC 7ppm, CC .5ppm. So I figured I lost roughly 2.5ppm overnight using the HAS/DPD test. I waited 4.5 hours and at 10:30 am tested again. FC 1.5, CC 0, a 5.5 drop in FC in about 4.5hrs.... Still no noticeable algae present, just a bit of cloudy water. But that is still improving. Again prior to adding CH and Ca Hypo 3 days ago the water was crystal clear.

Frustrated I opted to double check my reading at pool store # 2 and to get some more advice. I arrived at pool store # 2 at roughly 11:30 or an hour after my 10:30 am HAS/DPD test. They recorded CYA 75, TC .6, FC .6, Alk 91, CH 289, Ph 7.6 and no metals. This pool store requested I shock with 2lbs of bioguard smartshock sodium dichloro-s-tri…. 63.05%, available cl 39%. I inquired about cya levels and adding this shock (from all the reading I’ve been doing from you guys) Pool store said no cya in this shock (which again after all my reading seems to be false, correct?). They also blew off the cya deal, and told me to fill my floating chlorinator up with trichlor tablets and let her rip. This is basically the same advice the first pool store gave me, (shock and add trichlor back) and 24hours later shock burned up and chlorine disappearing fast when added during the following days.

I’m pretty much lost at this point. I opted to buy a couple bags of pool store #2 shock and give it a try, but it seems like after all the reading I’ve done about cya I’m just spinning my wheels again and am not accomplishing anything other than bringing up the cl for a short period of time and adding more cya to my water. I haven’t added this shock yet.

Would draining off 1/4 or so of pool water a couple times (have to be careful with the fiberglass pool, but not too worried about the water table with as dry as it is in California this year) and refilling be a smart move? I would hope to get the CYA down to 50ish, and bring the CH level down a bit as well (not that the CH matters all the much in a fiberglass pool, again from what I’ve read). I’m guessing you guys are going to say to jack the Cl levels way up and hold based on my CYA. For how long I don’t know. I really just don’t want to spend a fortune in Cl to accomplish this, and from what I’ve read draining and refilling at least some might help with that by lowering CYA and making the chlorine more effective??

I’m open to whatever at this point. Waving the white flag…..HELP!!!
 
First, stop trusting the pool store test results and stop listening to their advice. The "shock" they are selling you is just raising your CYA level, which makes it more difficult to solve the problem. Likewise they are telling you to use way less chlorine than you actually need to use, dragging the problem out, and tricking you into buying yet more stuff from them later. Not to mention telling you that dichlor does not contain CYA, which is just wrong.

Say your CYA is now around 75, that means you need to raise the FC level to around 30, and keep it there for a while, to make serious progress to cleaning up your pool. Alternatively, you can replace some water to get your CYA level down to something more reasonable, and use some somewhat lower FC target levels.

Your CH level is fine around 300. But CYA is now higher than recommended (because of the dichlor you have been adding, which contains CYA).

I recommend replacing some water to get CYA down to around 50 to 60 and then SLAMing your pool. See the section in Pool School in the How To section on SLAMing.
 
Ok, working on replacing some water now. Haven't added any, and won't add any dichlor. the only thing that I've added since last Friday is the CH and the Ca Hypo pool store # 1 suggested.

B/c of the fiberglass pool I plan on dropping somewhere around 1/4 of the water and replacing, as I don't want to add to much and have fiberglass problems. Rather be on the safe side. I plan to drop 1/4 today and refill and drop another 1/4 tomorrow and refill. That should get me in the realm of 50-60 CYA. I'll check CYA with my TFT CYA test kit.

With this replacing water regime going on for the next couple of day is it worth adding copious amounts of Cl at this point or should I wait, get my water replaced, balance ph/TA, and then start my chlorine regime?

Thanks for any help you guys can offer. Newbie at this. Reading past posts has armed me with knowledge to catch the pool guys in there own lies!! I inquisitive when they said the dichlor shock didn't have any CYA. Wouldn't have known that if it wasn't for the knowledge gained on here. Appreciative of that.

In dropping 2.5ppm over night, does that suggest a possible algae problem. Even though the pool has been crystal clear (except for after CH and Ca Hypo was added). Seem like my past post scouring might suggest that.

Then again seems like some past post suggest the cl process is nearing completion when you can hold a stable FC through the night. Don't think I've got the Cl levels up to 30ppm yet so maybe a 2.5ppm drop means nothing at this point??

Thanks!
 
You do want to maintain some chlorine in the pool, but I wouldn't try to add large amounts during the water replacement process.

Losing 2 ppm of chlorine overnight does suggest there is still a little algae somewhere, though there are a few other less likely possibilities. When you are slamming the pool, try to brush everywhere, making sure to get behind ladders, and into every corner, etc, just to make sure the high chlorine levels get everywhere and any biofilms that might exist are brushed off.
 
You sir are on the right path. Ignore the pool store - see the SLAM (Shock Level and Maintain) in Pool school. a 2.5ppm loss overnight means the CL was eating the algae. Keep at it, you will be doing the clear pool dance in no time.

Add the CL when you have the water down, that way you are keeping the algae at bay - good plan with doing small increments.

Yes - you can have a clear pool with an algae problem... as you are experiencing. given a week of neglect it would look like a pond.
 
If you have a light in your pool be sure and check for algae behind it as well. That is one of the places algae can hide.
Keep in mind it may take more than two 1/4 drain/refill cycles to get the CYA down to where you want it. When you add fresh water it will mix with the existing water, so the next 1/4 drain will have a lower concentration of CYA than the first 1/4 drain, so don't get discouraged if you are draining more water than you expected to bring down the CYA.
 
If your cya is 75, draining 1/4 will drop it to 56.25 draining a second 1/4 will drop it to 42.19. You want to be careful you don't lower it to much or you'll end up using that dichlor and unnecessarily spending too much on water.
 

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About done with my second draining of 20-25% of the pool water. Probably start slamming tomorrow. I read that you are suppose to get the Ph back to 7.2 -7.5. Can I do this the same day I start the slam? How long do I need to wait after adding ph up/down to adjust my ph to when I can check it again to make sure I'm within 7.2-7.5 and then start adding chlorine?

Is it also worth balancing TA prior to slamming as well?

Thanks!
 
Yep. Checked it this morning after the first drain. Down about to 60ish....on the 2nd 1/4 drain now. Refill tonight, check CYA in the morning using my TF kit, check the slam level I need to achieve based on the cl/CYA chart, balance ph between 7.2-7.5 and start dropping chlorine. Might try to crawl in the pool tomorrow and scrub light, ladder, etc prior to dropping CL.

Anything I'm missing???

Once I start slamming do I really need to run the pump 24/7, or will something along the line of 12-14hrs suffice? I know I need to check the cl levels multiple times during the day/night, sweep, and vacuum. Thanks.
 
Welcome!!! You can definitely adjust pH tonight, filter for a half hour or so and recheck. Also grab a sample for your CYA test and start the SLAM tonight. No reason to wait til morning and you'll get the most out of your chlorine doing it under the cover of darkness! Keep your pool running 24/7 during the SLAM. :goodjob:
 
Particularly during the first part of the SLAM process you will need to frequently check and boost your FC level, every hour or two is not inappropriate, as you go along you will see that the FC will tend to last longer and longer. Also we tend to suggest to use only liquid chlorine / bleach for the shock process, while your CH is probably low enough to safely use Cal-Hypo, there is an issue with Cal-Hypo causing the water to become cloudy which can confuse matters when your trying to clear up an algae bloom.

Ike
 
Well I'm on my way. Ended up draining the pool down 3 times at 20% each time. Got my CYA to between 45 and 35. Adjusted my ph from 7.6 to about 7.3 last night, and dumped 3.5 128oz bottles of 10% liquid chlorine, which should have brought my Fc from 0 to 25+(prolly a little overkill as with my CYA shock level should be about 16-20 but wanted to be safe to send er' off). Checked FC at 5:30 this am and down to 18. Added another 128oz bottle of 10% cl. just check it again (9:30) and stopped adding FAS/DPD drops once I hit 48 and the color was still pink (what's the point right, just saving solution).

So I guess I'm on my way!

Quick question. Since I'm sure my CH level is a bit low now, and I have about 4 1lb bags of 73% ca hypo on hand, would it be ok to supplement with these for liquid cl until they are used up? Thanks!
 

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