Cloudy pool - test results

Apr 22, 2008
7
Cape Carteret, NC
I opened my pool two weeks ago and the water was crystal clear until this past weekend. Algae started to takeover, so I brought the chlorine up to around 10. The pool turned green until about two days ago, now it appears to be slowly clearing up. I ordered the TF-100 kit and did my first test last night. Here are the results:

FC 12.5
CC .5
TC 13
pH 7.3
T/A 130
CYA > 100
Temp 71 F

I keep my Borates at around 50.

Here is an image from this morning. I would appreciate any insight into my readings. I have family in town this weekend and although the pool looks better than it did earlier this week, I am frustrated! I have this problem every year, but usually not until July/August - when the water temp gets above 90.



Thanks,
Shannon
 

duraleigh

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Apr 1, 2007
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Hi, Shannon,

Welcome. Your's is a common issue. YOu have too much CYA in your pool.

As a result, you must keep your chlorine levels up very, very high to prevent algae. I would bring the chlorine up to 25ppm and HOLD IT THERE until your pool is completely clear.

Then, because of that high CYA, you must keep your FC around the 10ppm level for the rest of the summer. If you do not, it will turn green again.

The cure is to drain a good portion of your pool water to dilute the CYA.

PS - You're close on getting it clean. If you'll get the chlorine up, I think another 24-48 hours and it'll be perfect.

It's fine to swim in with high chlorine because the high CYA in your pool reduces the chlorines effectiveness.
 

IkeRay

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May 20, 2007
154
Houston, Tx
The "difference" between FC and TC is the CC (combine chlorimites). You want to raise FC, but you also want TC and FC to be as close as possible, a CC level (or TC-FC) of >1 typically means you need to shock.

curious, what kind of chlorine are you using? also, specs on the pool (size, salt water generator?, filter type, you know the pool things)?
 
Apr 22, 2008
7
Cape Carteret, NC
I am using just Wal-Mart brand liquid bleach (6%). The pool is 16.5 x 32.5 - 8 feet at the deep end - about 20,000 gallons (if I recall correctly). I am using a 22 Hayward sand filter, one hp Hayward pump, and an Ultra Pure Ozonator.

I am getting ready to head out to add a few more gallons of bleach. Sounds like I need to drain about half the water out of my pool at the end of the season :roll: ? Thanks for the advice!
 

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looks like a nice pool though, and it also looks like your dolphin was just shot and he keeled over:lol:
 

duraleigh

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Shannon,

In the clearing process you're going through, keep an eye on your pressure guage on the filter. If it goes up by 30% or more from normal, be sure to backwash (clean) to remove the dead algae.

Another Carolinian! We're gaining on those Texans!!
 

IkeRay

Well-known member
May 20, 2007
154
Houston, Tx
shannonadams68 said:
I am using just Wal-Mart brand liquid bleach (6%). The pool is 16.5 x 32.5 - 8 feet at the deep end - about 20,000 gallons (if I recall correctly). I am using a 22 Hayward sand filter, one hp Hayward pump, and an Ultra Pure Ozonator.

I am getting ready to head out to add a few more gallons of bleach. Sounds like I need to drain about half the water out of my pool at the end of the season :roll: ? Thanks for the advice!

from a cost perspective, it might be more convenient to do the CYA drop now before the season seriously starts. call your MUD district or water source (city?), many will give significant discounts if you are filling a pool since you don't have to pay sewage.
 

chem geek

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Mar 28, 2007
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San Rafael, CA USA
shannonadams68 said:
I am using just Wal-Mart brand liquid bleach (6%). The pool is 16.5 x 32.5 - 8 feet at the deep end - about 20,000 gallons (if I recall correctly). I am using a 22 Hayward sand filter, one hp Hayward pump, and an Ultra Pure Ozonator.

I am getting ready to head out to add a few more gallons of bleach. Sounds like I need to drain about half the water out of my pool at the end of the season :roll: ? Thanks for the advice!
Do you have any idea how the Cyanuric Acid (CYA) level got to be so high? Was that a carryover from a previous season where Trichlor pucks/tabs were used or Dichlor for shocking or was too much Cyanuric Acid added directly at some point?

The CYA level is probably pretty high -- probably 150 ppm or more -- since even the Borates and the ozonator weren't able to keep the algae at bay when the chlorine level was presumably lower. Anyway, I agree with the advice that it might be cheaper for you to deal with the partial drain/refill now, even if that just results in a CYA of 70-80 which would still be manageable keeping the chlorine around 7-8 ppm FC.

You say you usually get algae every year in July/August. Hopefully, with the help of those on this forum, that won't happen this year.

Richard
 
Apr 22, 2008
7
Cape Carteret, NC
Ok, two days later...here are the readings and how the pool looks. It is much better, but still a bit murky. I have added about three to four gallons of liquid bleach since Friday and probably should add a few more gallons?

FC 15.5
CC 0
TC 15.5
CYA > 100
Temp 75



Although I really dread it, it sounds like I need to drain a portion of my pool. I am going to hold off a bit for now, but will probably since start draining about 10% and refill every week or so starting next week.

I used the 3" Tri-Chlor tablets for two and half seasons and switched to liquid bleach and high Borates in the middle of last Summer. So, that would explains the super high CYA. Any thoughts on the latest readings?

Thanks to everyone!
 

JasonLion

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May 7, 2007
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It looks like you are doing well. Keep the FC above 15, as you have it now, and keep an eye on the filter pressure and backwash/clean the filter as needed and things should continue to improve.
 

sevver

Well-known member
Mar 27, 2007
477
Morris, IL
I would think that if you drain about 10% a week, it would use more water to reach a desired CYA level than if you just drained 50% and got it over with. You can drain it using several garden hoses so long as you have some place lower in your yard than the midpoint of the pool, which it looks like it could be over next to the trampoline...