Need some Advice

[James Curtis]

Hello, I'm new to the pool thing and just bought a house with a pool. It's about 25-30K gallon pool with Plaster. When I first got it, it had a CYA of 200!!! The pool wouldn't hold chlorine, and previous owner used and kemtech shock packs and 3" puck tablets in a floating chlorinator. I had brown algee growth after 1 day of not using the chlorine pucks. I knew enough to read about it and drained the pool and got CYA down to about 70. I also want to stop using the pucks. Here are my current readings:

CL .5
PH 7.5
Alk 80
Calcium 150
CyA 70

Because I just drained the pool to ge the CYA down to this level, I want to try to work with it before I do anymore. We threw in 2 gallons of liquid chlorine 12.5% to shock it and it raised the chlorine up to 5-10ppm.

I'm in Northern CA where I'm currently getting about 12 hrs of sun a day on the pool, temps are in the 70's -80's right now, and will get up to 100's in summer. My question is what should I keep my CL level. I'm going to try adding just liquid chlorine (bleach) and want to stop using the pucks. I was told by a pool professional who helped me with the CyA issue to keep it at .5-1.5 but everything I read here says to get the chlorine up to 5ppm for a pool with 70 CyA in it. The pool is crystal clear at the moment.

 

[jblizzle]

Welcome to TFP!!!

First, what test kit are you using? Is it one of the Recommended Test Kits? The FAS-DPD chlorine test is an absolute must.

Second, a FC of 10-12 is no where near high enough to "shock" the pool. You need to follow the SLAM Process and according to the FC/CYA Chart, you need to be maintaining a FC level of 28ppm based on your CYA of 70ppm.

Once you pass the 3 criteria to stop the SLAMing, then you will need to maintain the FC above 5ppm at all times. So you would dose up to about 8ppm everyday to ensure it never dropped below 5ppm.

 

[James Curtis]

Thanks for the reply jblizzle. Here is some more info. I bought a Taylor K-1004 trouble shooter which lets me read FC, PH and Alk. I have been getting my other readings from my pool inspection company (they don't own a pool store so don't sell me nefarious chemicals, etc and have not incentive to do so). I can certainly buy one of the other kits as soon as I get a better handle on what I'm doing to test the other components myself.

I just tested again a few min ago and here is what my kit gave me:
Fc 1-2
Tc 2-4
Cc1-2
Ph7.5
Alk100
Do I need to even do a slam, as it stands right now the pool is very clear. I'm trying to stop using the pucks and go directly to liquid chlorine, and haven't done this before. So I am trying to figure out if I can just maintain at this point, i.e. just add liquid daily based on my current readings, and if so how much.

 

[Smykowski]

Do I need to even do a slam, as it stands right now the pool is very clear. I'm trying to stop using the pucks and go directly to liquid chlorine, and haven't done this before. So I am trying to figure out if I can just maintain at this point, i.e. just add liquid daily based on my current readings, and if so how much.

The only way to determine definitively if you need to SLAM (or not) is to do an overnight chlorine loss test.

If you're going to maintain, use PoolMath to determine how much to use.

See Pool School for more info.

 

[Richard320]

Welcome!

You do need to SLAM, if the CC reading is to be believed. And that will be difficult with CYA of 70.

If you decide to leave CYA at 70, you'll also need to maintain FC above 5 all the time, which is the limit of most colr matching test kits. So you Won't know if you added enough to get to 8, or if you're at 10, or what. All you'll know is when you went too low.

Best value is a TF100. You can get it at http://tftestkits.net or through http://www.poolsupplyworld.com/TFTestkits-TF-100-TFTestkit-FAS-DPD-Test-Kit/TF-100.htm