Still don't understand CYA or filter problem?

[RH60]

Sorry post is so long but really appreciate any suggestions.
I have had a pool for about 20 years and always just used the pucks in a floater. Never really a problem. Then a couple of years ago seemed to always get a algae problem.
Received a lot of great advice here and bought the Taylor K2006 kit. Seemed most of my problem was with a high cya from the puck and so was not getting high enough to shock.
After last year I thought I had it under control and understood thing a little better.
This year water has been very clear so I was only keeping up with the FC and PH since it was clear.
Then after a few storms it was clear needed to be vacuumed. Maybe a total of a cup of dirt spread around the bottom. Wife just brushed it and it made it a cloudy. But always before it would clear up the next day.
Did a test with the Taylor kit. Shocked the pool and run pump 24 hrs instead of 8 hours a day. Also change my pump speed from ½ hp to the 1 hp on this new 2-speed pump.
Been a couple of days and just a little better. Below is the results BEFORE I shocked with bleach using pool calculator.

FC= 13
CC = 0
PH = 7.8
TA = 90
CH = 70
CYA = 100

Now I have been using a combination of 1 puck every 2 weeks and they rest bleach. With limited use of the pucks I thought would not get the CYA too high, but of course it is. End of last year I had it down to CYA 60.

But this is what I really don’t understand. Used only the pucks for years with no problem. About 2 a weeks but never tested my CYA.
My next-door neighbor has the same size AG pool and his stays very clear with none of the problems the past few years. He uses same pucks and just fills his floater once a month. So 4 pucks and twice as much as I use both it really stay clear. Only other difference is he has a 150 lb sand filter with a one HP pump on our 18 AG pools. I have a 20 year old 100 lb sand filter and have been running new pump on low speed.

So my questions.

I guess my problem again is high CYA?
But why not ever my neighbors and could I have some other reoccurring problem?
Did test a sample of his water and his CYA was 100 also and could not even get a reading for FC. He said he was due to put in more tablets. Could not believe it, and his was clear.

What do full service pool service companies use if not pucks or do they visit each day?
I am gone a week at a time sometimes.

Should I replace my 20 year old MFM17 Jacuzzi brand sand filter?
4 years ago I took it all apart to inspect and everything looked great. And this one just fits under the deck area and most I have seen are taller so would be a little problem.
Not sure if it could be a filter problem. Water just cloudy and not really green like last years problem.

Thanks again for any advice.

 

[Butterfly]

One of the problems with CYA of 100 is that no test can confirm if it is 100 or 200. It tests pretty good up to about 90, then :?

Try re-doing the CYA test using a 50/50 mix of pool and tap water, then double the result ... that will allow you to maybe get a better estimate, especially if it is > 100ppm.

So yes, the CYA appears to be your biggest problem.

btw, have you cleaned the sand filter?

 

[zea3]

Your neighbor may vacuum to waste, and backwash for longer periods of time or more frequently. If he does then he is replacing water more frequently and may be doing so often enough to keep CYA in check.

 

[RH60]

Your neighbor may vacuum to waste, and backwash for longer periods of time or more frequently. If he does then he is replacing water more frequently and may be doing so often enough to keep CYA in check.

No neighbor does not vac to waste and vacs a little less but I tested his CYA is 100 and pool stays clear.

I did just recheck the pool calculator. Sorry I did make a mistake on that. I add 96 oz of bleach instead of the 321 oz. Have just added more bleach a minute ago.
Would it be considered a waste to replace the 20 year old sand filter. Still looks good and seemed to operate good until this problem. May try to find the time tomorrow to pull the top off and at least check the sand level.

 

[Isaac-1]

As has been mentioned try rerunning the CYA tests with the samples diluted 50/50 with tap water, and you may find that his CYA level is much lower than yours (100 vs 150), also algae taking hold can be a combination of how consistent the chlorination is, what falls into the pools, how much sunlight the pool gets, etc. So even pools next door to each other may get different amounts of exposure, then of course there is the question of splash out, backwashing and other causes of water replacement that will dilute CYA, but in the end it may just be a matter of luck when pushing CYA levels to the edge.

 

[jblizzle]

The filter does not cause or prevent algae ... if the cloudiness is indeed due to algae. Since you have likely not had a high enough amount of FC for your CYA ... something is likely growing.

You should certainly inspect/clean your sand and settle the sand bed to be sure it is in good shape ... you should be doing that every year:
my-sand-is-channeled-how-to-fix-it-t7626.html#p60821

No telling why yours is cloudy and theirs is not ... maybe they are just lucky for now.

At this point you need to lower the CYA and follow the shock process.

 

[RH60]

Thanks for all the great advice. Still cloudy but does seem a little better. And the color is now more of a blue instead of a slight green.

I did go ahead and check my sand filter. Everything looks good inside. Was just going to inspect. But was not much more work with a wet/dry vac to go ahead and replace the sand.

The filter is 20 years old and is fine now. But sooner or later will need a new one. . Mine is under a deck with limit height since the AG pool is in the ground about 20". Diameter is no problem but I will have some problem with height. Hard to find this info on the web even from Manufactors websites.From what you have seen, who makes the shorest sand filter?

Thanks

 

[duraleigh]

Would it be considered a waste to replace the 20 year old sand filter. Still looks good and seemed to operate good until this problem. May try to find the time tomorrow to pull the top off and at least check the sand level.

Even though the filter is not related to the presence of algae, I think it is still a good idea to pop off the top and take a visual inspection of your sand bed and probably clean it if it has been more than a year since you last did so. Not to fix the algae issue but to make sure your system is optimal.

Secondly, I know you know this but it really doesn't matter why your neighbors pool is behaving differently.....he probably is simply lucky but there are too many variables to try to analyze his pool management.

What does matter is how to keep yours crystal clear so you can enjoy your pool. The biggest contributor to your problems certainly seems to be your very high CYA so I would fix that by getting your CYA down to around 50 ppm.