Question about Water Clarity

Jump to latest Follow Reply
R

Ratboy

0
Nov 28, 2015
14
Hunters Hill, Sydney, Australia
Hi All,

I've searched around a bit but can't seem to find anything in Pool School in regard to the causes of (slightly) cloudy water.

My issue is that my pool, whilst relatively clear, doesn't seem to be as "crystal clear" as it used to be and I was just wondering what potential causes might be. Obviously filter issues are one, but given my cartridge filter is a new install, I doubt that's the issue. What are the potential other causes? CYA/FC ratio?

My latest results are:

FC: 4.5
CC: 0
TA: 75
CH: 350
pH: 7.6
CYA: 75
Salt: 7000

Any suggestions welcome!
 
So I've figured something out... On a retest this morning my FC level is way down (0.8), and I'm hoping it's because I turned the salt cell down, and not some other reason. I loaded the pool up with chlorine to get FC back towards 5. The pool is looking clearer already. Once I've got a steady chlorine level I'll do an OCLT.

Another interesting thing I discovered is that with FC at 0.8, CYA increased from a previous test of 75 to a result this morning of 90 - or is that just test variation?

Jim R - I used to have a sand filter (that spat most of the sand into my pool :cool:) - the differences with clarity have all been with the new cartridge filter, so it's not a filter change issue.
 
I'd just try and get your FC level up to about 10 and then perform the OCLT, the sooner you can confirm the clearer your next plan of attack should be. I'm sort of assuming if you have a reading of 0.8 which is is quite low from possibly 5ish taken late yesterday then algae could be it.

Your higher CYA reading is likely from a testing variation - it is around +/- 15 error range when you take the reading.
 

Enjoying this content?

Support TFP with a donation.

Give Support
You are now exhibiting two classic symptoms of an algae bloom. Lower than expected chlorine and cloudy water. Algae is likely consuming your chlorine which can be confirmed by OCLT. But that must be done with the SWG off. We recently revised the process to not require raising FC to 10 ppm prior to beginning the test. FC of 3 ppm or greater is sufficient. What is most important is accuracy of the test sample size and making sure to hold the bottle vertically and form good drops. Consistency from test to test is also an important aspect.

More here, Pool School - Perform the Overnight FC Loss Test (OCLT)
 
Unfortunately, if a bloom is in the making, a short burst of FC won't resolve the problem. Algae is just that stubborn. Performing the OLCT would be your best approach as noted by pooldv. The results of that OLCT will confirm whether you have algae or not.
 
So.....the OCLT results are in. Last night at 8pm FC=6.2ppm, this morning at 6am FC=5.2. That's a loss of 1.0 - and according to the test that means I should be OK.....just! Or is it too close, and I should be worried?

wjr75 - in terms of clarifier, is that just a pool shop purchase, or is there a cheaper alternative? Is this just for new cartridges? Mine is about 4 months old.

Again - thanks heaps for all the advice here!
 
Last edited:
There is generally no need, or even benefit, from adding clarifier. Not to dispute the good luck wjr75 has had with them, but the anecdotal evidence of "seems to help get the filters going" is not the type of science based advice the forum generally follows.

Clean cartridge filters alone, with properly maintained water, will be plenty sufficient to obtain/maintain sparkly water. If it has gone off of sparkly, a SLAM will return it to that state.
 
I was just pointing out that it had helped me in the beginning of the season not that I use it all the time. I'm an Engineer and after reading a lot about other scientific stuff over the years a clarifier that is a coagulant helps clump finer particles together which may help in filtering. I have my pool power washed every spring so this seems to help getting rid of any plaster residue. I have also heard people add some DE powder to both a cartridge filter and also a sand filter to get similar results. I have not tried this out ever on my cartridge filter.
 
Fair enough. After all, understanding what goes in and why/what it does +/- is the key.

Does seem like a SLAM is in order in this case before trying a clarifier though, as OP is on the edge of not passing the OCLT (with a loss of 1.0), AND has cloudy water.
 

Enjoying this content?

Support TFP with a donation.

Give Support
You must log in or register to reply here.
Thread Status
Hello , This thread has been inactive for over 60 days. New postings here are unlikely to be seen or responded to by other members. For better visibility, consider Starting A New Thread.
Top Bottom
Back
Jump to latest Follow Reply