Help pool gine green with a lot of rain!

squibcakes

Well-known member
Sep 20, 2015
55
QLD Australia
I've been away for 2 weeks and ensured my pool balance was correct before I left. Pool clarity was excellent!

However I have come back to a very green pool. I did a quick test FC test last night and it was over 10. I was expecting it to be like 1 or zero... in any case i threw in 2 litres of bleach, upped the swg to 100% and let run over night.

This morning I did a thorough test.
FC 12
CC about 1
pH 7.7
TA 70
CYA 65

Threw in remainder of bleach about another 1 lt, and 2kg Bicarb and turned acid feeder to max.

I always shoot for FC of 6, but have noticed this year due to a lot of pollen i have had to run FC quite higher to keep things clear. Occasionally I have had a pool store test which shows i have very high Phosphates and have found that using a phos clear and clarify does indeed clear things up but not the route cause.

My goal today after work is to lower ph and start a slam. Any other recommendations?
 

YippeeSkippy

Mod Squad
LifeTime Supporter
Jan 17, 2012
12,021
Evans, Georgia
Squibcakes, I'm confused as to why you added any bicarb? Your TA is fine. Your pH isn't accurate if your FC is over 10.

After adding the 2 L of bleach (what concentration?) did you retest to see how high you got it?

If your pool is green you need to perform a SLAM --> SLAM Process <--instructions

You need to take your pH down to about 7.2, because once you start the SLAM your pH tests are skewed.

I don't think the rain was the root cause of your green, but at this point all you need to do is SLAM.

We don't recommend the use of phosphate removers or clarifiers if you're keeping your FC up to snuff with your CYA level. See this--> [FC/CYA][/FC/CYA]

Maddie :flower:
 

AusJohn

Active member
Hi Squibcakes,

Are you in the part of QLD that's been getting the sort of rain that drowns you if you look up ? Has the pool been overflowing or had a lot of debris washed in? If not, the pool going green with those numbers would indicate that there may be an issue with the test.

Since you're in Oz, whose test kit are you using for the CYA test ? I know of at least one commercially available kit here that has been having issues with CYA reagents. The reagents have been reading low. I suspect that this is an issue with biological degradation of the reagent and standard, both CYA (standard solution) and Melamine (detection reagent) make excellent bug food and these dilute solutions would have to be stabilised either by sterilisation or addition of a biocide and preferably both. If your reagents have gone off, you may have more CYA in the pool than you think resulting in a low FC to CYA ratio.

If you have a local pool shop who use the Waterlink Spin photometers, I have found their CYA test to be very reliable and operator independent, ie the lighting, mixing, mixing time and operator variability are pretty much eliminated. I think Poolwerx in Australia use these units nationwide if that's any help. I would suggest verifying your CYA level before starting a SLAM as you may need to dump water and top up.
 

squibcakes

Well-known member
Sep 20, 2015
55
QLD Australia
I use CCL test kit. The powder is a bit old, but the titration agent is new. So the change point is not so clearly defined.

i just checked my FC and it is now 13.5. Ph is 7.2 after adding 1lt of acid.

The liquid chlorine is 12.5%.

i found the cya tests I do are very close to what pool shop using photo tester shows and it was 59 a few weeks ago.

im in sth qld getting all the rain, and have an overflow pipe in skimmer so all surface water does drain away and I don’t get any flooding from garden etc.

i will do slam and see hope for best
 

AusJohn

Active member
That's good,

I've had two sets of reagents from them for CYA and have never hit a result of greater than 30. Thing is I just refilled the pool before getting the kit, know exactly how much stabiliser I added and the photometer test matched within a few ppm. Not only that but some back of the envelope calcs on water losses to filter cleaning tracked the CYA concentration changes near perfectly. The CCL test is giving me a result less than half of what is actually there, which is why I thought I'd check. I've raised this with them and they were aware of it and have been very good communicating and replacing reagents. They're good to deal with but it's a little frustrating when the chemistry doesn't work.
 

squibcakes

Well-known member
Sep 20, 2015
55
QLD Australia
Been SLAMing last couple of days and so surprised how quickly the water has gone from dark green to murky green, murky, to cloudy.

Over night FC test appears to have past although quite difficult using older dpd powder.

Just want to know at what FC level is it safe to throw my robot into the pool and at what FC level can i retest the ph and other readings?
 

YippeeSkippy

Mod Squad
LifeTime Supporter
Jan 17, 2012
12,021
Evans, Georgia
No need to do an OCLT if the water is still green. Save that (and the reagents) for when the water is clear again and you just need confirmation all is gone.

You can put the robot in again. FC doesn't seem to affect them that I'm aware?

Maddie :flower:
 

Teald024

TFP Guide
The FC level should be fine for your robot. The relative FC isn't all that high at +/-20% of CYA.

If the water is still cloudy, there is no point in doing an OCLT, but its good to know that FC consumption is fairly low at this point and most of the heavy algae is dead.

The pH test requires the FC to be below 10ppm to work properly. The other tests aren't sensitive to FC at your levels. Don't worry about your other readings at this point. Just work on the SLAM until the water is clear. Then you can work on balancing the other stuff, if needed.