New Owner Question

[Edd]

I'm somewhat new here. I've searched through the forums but it seems the best results come from posting pool type, size, equipment, etc. with current chem numbers so here it goes.

Dallas/Fort Worth area
(will add to signature later)
30,000 gallon in-ground pool
Pentair FNS Plus filter
The pump make/model has been worn off but seems to be working great
AquaRite SWG and Turbo Cell (not currently in use)

We moved into this house about six months ago. For two months I just hired a pool service (same one previous owner used) to open up and maintain the pool until I could take over myself. Turns out, the pool has been running as a non-saltwater pool for five or so years now. The SWG controller seems to be working fine and there is no scaling on the cell. Salt is how I'd like to run it and am now starting the process of doing it that way.

My question is this, how much salt should I add to begin with and what should my settings on the controller be?

Also, (and this may be best responded to in the algae forum) there is some slight algae buildup (nothing that can't be brushed off it seems) around the bottom of the pool. I've attached photos….I think.

My numbers are below. I am happy to use the pool math section but am unsure of what my target numbers should be.

Any help is appreciated.

FC 4.6
PH 7.3
TA 60
CH 270
CYA 70

 

[jblizzle]

Please put your details in your signature as described HERE as it will help us help you.

With algae in the pool, you need to follow the ShockLevelAndMAINTAIN Process before you worry about the SWG. To do this correctly, you will need to invest in one of the Recommended Test Kits.

Get the kit (or do you have one already?) and we can get your straightened out.

For the SWG, you ware going to want to test your salt level to figure out how much additional salt you need to add.

Have you discovered Pool School yet? Start with these:
ABCs of Water Chemistry
Recommended Pool Chemicals
How to Chlorinate Your Pool
Water Balance for SWGs

 

[Edd]

I bought the Taylor K-2006 test kit. That's where I got the numbers above. Will that kit work? The algae is not bad…just the couple of spots you can see in the pictures.

 

[Edd]

Do I need to SLAM if the water is relatively clear?

 

[jblizzle]

OK good!!!!

Any visible algae = SLAM process.

Your pH is good, so you just need to boost the FC up to shock level (28ppm for your CYA of 70ppm) and maintain it there until you pass the 3 criteria to stop.

BTW, use a 10ml water sample when doing the FAS-DPD chlorine test so each drop is 0.5ppm and you will not run out of reagent as fast ... BUT ... you should order FAS-DPD and CYA reagent refills now since the K-2006 is so stingy (which is why we generally prefer the TF-100 )

 

[Edd]

I noticed the CYA of 70 is not recommended. Should I do something to lower that?

 

[jblizzle]

Well that is a bit of a conundrum ....

It is easier to SLAM at a lower CYA level ... But ... for a SWG you want the CYA up at 70-80ppm.

So you either have to pay to replace 50% of the water, SLAM at the lower FC level, then buy more CYA to raise it back up
Or
You just can SLAM at the higher FC level (which really should not use that much more chlorine over the process), but will require more reagent.

I would opt for the later.

 

[Edd]

Yeah, saw the chart for the SWG pool after I posted…too quick.

Really appreciate the help.

- - - Updated - - -

Okay, one more newbie question: if I'm using liquid chlorine, how do I know how much to add at a time?

 

[jblizzle]

Simple ... PoolMath calculates it for you based on your current FC and your desired FC level.

 

[pooldv]

Welcome to TFP!

Once your SLAM is finished you can use Poolmath to calculate how much salt to add. Do NOT assume that starting salt level is 0, there are lots of things that add salt to pools over time. It would not be surprising if you have 300-500 ppm or more of salt right now. You will need a salt test. Tftestkits.net sells them.

Here is the Water Balance for SWG Pools
And here are Recommended Pool Chemicals and how to add them.