High CYA, TA, Normal ph and Fc--still have algae

[Zdruiz11]

So I just recently took over cleaning my pool-I have a genera idea of how things work. I am a hazmat technician/engineer for a fire dept, so pumps and chemicals I understand, but some of this pool Chem is a little different!

Plaster pool, 20,000 gallons 36 sqft DE filter (working really well, just cleaned grids and fresh DE. Running at only 4 psi)

FC 3
TC 3
CH 500
CYA 150
TA 140
Ph 7.4


I know that I need to drain the pool to fix CH and CYA, but I have to wait till winter. It's 105degrees and up now. The problem I'm having is that I think that the CYA is too high to combat algae-even though my FC is in a good range. The FC/CYA ratio won't work, because my CYA Is way too high to achieve a FC or more than 9.

Also-I know my TA is a little too high-I just don't know what to do first.

Any help, thanks!!!

Zack

 

[AimeeH]

Hello there and welcome to TFP

we can get you on the right path of pool chemistry management if you want to learn

Can you tell us.......how are you testing to get those results?

And how are you chlorinating?

 

[kabutotx]

Get a good test kit like the Taylor 2006 or TF100 if you don't have one. Others and the pool stores are pretty bad.

Your FC is always dependent on your CYA. See the Chlorine/CYA chart in Pool School.

Too hot to drain so just try to keep your FC at least at 12 or higher. I had the same high CYA last summer 9and high CH) until I drained the pool and kept it at that range with no problems..

 

[tim5055]

Yup, your CYA is not in a good range - unless you listen to the pool store. For a CYA of 150 your FC should never drop below 12.

 

[aussieta]

from memory you need to maintain FC at least 7.5% of cya
to combat algae slam at 20% of cya
so for 150cya you need minimun 10fc and to slam 30fc
you could use the tarp method for a partial drain
Reducing CYA, the Tarp method

 

[Zdruiz11]

Hey! Thanks for the response. The above test was done after bringing my water to Leslie's and they tested it. I have a test kit, but it's a generic 4 way test kit. It doesn't test FC (or CC for that matter) above 3 ppm. Ill have to get a better test kit. Leslie's told me my FC was fine, but I quickly realized that it was too low because my CYA was so high. I'm trying to see how I can raise my FC without also raising my CYA.

 

[Holydoc]

ZD,

You can raise you FC using liquid Chlorine. You can purchase this at Leslies or Walmart. Anything containing solid chlorine (powdered shock and pucks) contain a stabilizer which basically either adds CH or CYA. Both of these you do NOT need more of in your pool. Only use liquid chlorine/bleach.

 

[Zdruiz11]

Holydoc,
Thanks! how do I know how much liquid chlorine to use? I know if I follow SLAM, I just monitor, correct, until I reach the right FC?

thanks

 

[Holydoc]

ZD,

First off I am assuming you have a test kit like the one from TFTestkits.net:

TFTestkits.net

If you do not, you need to buy one now! Everything is based on your testing and your use and understanding of the tests from this kit.

For the SLAM, you would use the web based Pool Math:

http://www.troublefreepool.com/calc.html

Or the app PoolMath which is created by TFP, or even the web based app PoolLogger:

Pool Logger - Pool Chemical Log App and Pool Calculator

which was created by a user of the TFP methodology.

I would also recommend getting a CYA Standard sample for TFTestkits.net:

TFTestkits.net

The standard solution will show you exactly what the end results of the CYA test should be so that you know you are calculating the right end results. That was how I discovered that I was reading my results incorrectly.

That should get you started and set for a perfect pool.

 

[Holydoc]

Oh and for full disclosure, I am a USER and BELIEVER of the TFP methodology. I am not a moderator, developer of programs, or affiliated with any of the companies represented here on the forum. All I can tell you are from my experiences.

However The moderators here have years of experience that far surpasses my knowledge. Don't be afraid to contact them directly for help. The program developers of PoolMath and PoolLogger and super responsive and have incredible talent. Finally the owners of TFTestkits.net are active members/moderators of this board and are some of the nicest, customer oriented people I have ever purchased from. In other words, you are in good hands here.

 

[domct203]

from memory you need to maintain FC at least 7.5% of cya
to combat algae slam at 20% of cya
so for 150cya you need minimun 10fc and to slam 30fc
you could use the tarp method for a partial drain
Reducing CYA, the Tarp method

SLAM level FC is 40% of CYA, daily FC target is 12-15% of CYA, and never ever let your FC fall to, or below 7.5% of CYA.