New pool owner, first test results... seeking advice


Active member
May 29, 2018
Sydney, Australia
Now that I look on bunnings website, I can see liquid chlorine available in 15L for way cheaper... good tip for next time
Welcome to the forum. Those 15L ones from Bunnings are the go, you bring in the old containers and swap them whilst you are eating the sausage sizzle. That way the price is further discounted.

I'm a new pool owner too. All a bit overwhelming at first but the folks on here and the pool school book will keep you on the right track.

Well I let FC drop to 10 over the past couple of days

However, still a very faint green section of algea. Even after daily scrubbing, it's still faintly there - how long does it normally take to eradicate it completely?

I've dropped in a little more bleach to return FC to 12, I'll keep up the SLAM a few more days.


LifeTime Supporter
TFP Guide
Jan 18, 2015
Bunbury, WA, Australia
It sounds like you have passed the OCLT when performing the SLAM but the re-appearance of the algae post-SLAM could mean a couple of things

Firstly, I would retest your CYA which you have been adding a few times- reconfirm that your CYA is still 30 and not a higher number which would effectively mean that your SLAM level of FC needs to be maintained at a higher level than 12.

Secondly, you need to brush specifically in places where algae likes to hide- classic spots are light niches (may need to pull the light out), around skimmer boxes, around return jets etc.

Given that you have recommenced the SLAM (good move by the way) then checking these two things might be a good start.

The successful completion of a SLAM should mean the total eradication of the algae.
ok, now I'm totally confused...

So pool guy comes around and I explain what I'm doing and why, all good... my plan is to take over maintenance, but retain them for a little longer until I'm comfortable.

I explained that I have a test kit, and my CYA reading was very low so added stabiliser to 30, then chlorine to 12 to shock the algae.

I had to go to a meeting, so I left him to it and asked him to let me know the numbers he got from his machine.

Here's what he texted me:

pH: 8.1 (!)
CYA: 55
TA: 125

So he drops in a bunch of acid, back-washes etc and on his way.

This was a bit of a shock, as my initial pH and CYA are way different, so this evening (probably 3-4 hours after he left), retested... my readings:

pH: 7.0
CYA: 28
CF/CC: 13/0

Before I started SLAM, pH was ~7.3 (1 week ago), and had not retested while SLAM was continuing.

So... who am I to believe? brand new Clear Labs Kit (which I baselined), or pool guy with his electronic test kit?

Wondering how I can confirm the numbers.. or does high CYA explain why my algae is persisting?


LifeTime Supporter
TFP Guide
Jan 18, 2015
Bunbury, WA, Australia
Mixing the pool guys testing with the CCL kit is sure to cause confusion and you'll find yourself constantly second guessing yourself. You've got one of the best kits -use it and trust your readings.

It sounds to me like he has dumped a pile of acid which could be causing the lower pH reading. However, with a reading of 13 FC this will be inaccurate as you can't reliably measure pH when your FC is greater than 10.

You now need to make sure the pool guy hasn't poured so much acid in that your pH has dropped below 7.0. Drop your FC below 10, retest your pH. If it's reading 7.0 (not 6.8) then your good to go. Take the FC up to 12(if your happy that your CYA is 30) and resume the SLAM and fire the pool guy.

Just another thought- that if he backwashed the pool you will have lost some CYA so your actual level could have been closer to 40 than 30 beforehand. We generally round up our CYA reading when the black dot disappears between the 2 multiples of 10- i.e. if your reading is between 30 and 40 then always round up to 40.
hmm... not sure I'm winning this battle

I initiated the SLAM about 3 weeks ago now. Initially, the algea was fairly prominent localised patch, and it did start to clean up over several days. But it never quite went away... the pool is pebblecrete and it seemed like algae was left hiding in the cracks of some of the pebbles.

Anyway, I've basically let the pool settle back down to FC of 9.5 over those three weeks (the SWG is running 6 hours per day, so CF very slowly lowered).

However, today I notice the algea start to return in more small spots around the shallow areas.

Current values
FC/CC: 9.5 / 0
pH: 7.6 (I think... I find it very hard to read tbh so I've attached an image).
TA: 30 (I re-measured this using the high sensitivity test)


So, looking for some advice on where to go from here? Or what I might be doing wrong?


Gold Supporter
TFP Guide
grab a handfull of ping pong balls and throw them in
sit back and watch the show. if they dont go anywhere near your algae area you may need to adjust the eyeballs
hopefully they all end up in the skimmer after an hour or two