New pool owner

[poolguy2025]

Hello all,

We purchased a home with a below ground, 20k gal, textured/plaster pool + spa. For the last month or so I've been using a 5-way pool test kit and Leslie's to get all our measurements, but after getting a couple readings from Leslie's that seemed way off we ended up getting a Taylor K-2006 test kit. Our first test results show:

CYA 60
CH 625
TA 100 (80 if adjusting with 1/3 of CYA)
PH 7.8 (honestly, my color matching skills are pretty poor...3 or 4 drops of acid demand got me close to 7.2/7.3)
FC 7.2
CC 0

I was a bit surprised by CC levels. We've been seeing some discoloration on the sides of the pool and small amounts of what we are thinking is algae (i.e. quarter-sized) in the pool after having a house warming party about two weeks back. We shocked the pool with cal-hypo (Power Powder Plus - 2 1lb bags), and saw the discoloration clear up in a day, but never get crystal clear clean, so I figured our FC was still getting eaten up and was expecting to see *something* in the CC, or maybe very low FC.

Anyway - I'm looking at the ideal levels as suggested by TFP, and I'm seeing 350-550 CH and 40-50 CYA. I tested our tap and we're at 200 CH. I think draining a bit less than 1/3 of the pool and filling with that should give us the CYA of around 40 and CH around 500, which puts us into the "ideal" range for those, and then I can SLAM in an attempt to kill any algae that might be in there. After that I'd re-measure the TA and try to get to a decent CSI?

Thoughts? I'm mostly looking for some sort of verification before I do something stupid... =)

Oh, also, when people/tools mention the TA measurement, (e.g. "ideal" level in TFB being 60-80), is this the "adjusted" measurement where we remove the 1/3rd CYA? Or would the ideal be an "unadjusted" measurement of 60-80 in the presence of 40-50 CYA?

Thank you!

 

[PoolStored]

Welcome to TFP!!!

but after getting a couple readings from Leslie's that seemed way off

Welcome to #TeamPoolStored.

First, great job on the test kit.

CC is only one indicator of something being off.
Another indicator is the consumption of FC in in absence of UV. Great test/tool to confirm algae...Link-->Overnight Chlorine Loss Test
If you see visible algae, fail OCLT, or CC >=1, then SLAM. Link-->SLAM Process

A partial water exchange will lower your CH and CYA. With a CH that high, you might consider a larger exchange. With input water of 200, and evaporation, your CH will be a constant issue. It's a pay me now, pay me later type thing. You might also consider putting your fill water on a water softener. 200 isn't horrible, we have some members in the SW with CH fill water north of 300.
Check out "No Drain Water Exchange" here:

Draining - Further Reading

www.troublefreepool.com

TA is TA. No need to adjust for CYA. Raw TA # is just fine. In general, no need to "manage" TA. Just keep your pH in the 7s and TA should take care of itself.

Managing pH and Total Alkalinity - Further Reading

www.troublefreepool.com

PH TA Relationship - Further Reading

www.troublefreepool.com

In SD, you may find that a CYA of 60 will work very nicely to reduce your FC consumption. Staying at or below 60 will make the SLAM easier.
When you chlorinate, always follow this...Link-->FC/CYA Levels

Here's looking to your future pool! Link-->How Clear is TFP Clear?

 

[poolguy2025]

Thank you for the reply!
I took a look at the "Draining - Further Reading" to learn more about the "No Drain Water Exchange". It has a formula that determines whether we want to extract at the surface, or at the bottom of the pool, based on temperatures and TDS. I don't see an explanation of how to get the TDS numbers though, either in that article or on the pool math. Is there anything comprehensive to look to for determining TDS?

 

[PoolStored]

Most muni water supply is 500.
Typical pool is 1000 or so.
If you have an SWG then use the most recent salt reading.