Help for Beginner with old pool

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M

Misha T

0
Oct 16, 2014
12
Fresno/California
Hello,

Summers are sunny here in Fresno California, hot both night & day
Pool water stays really warm
Just now beginning to cool

Pool 30,000 gallon
IG oval
about 25 years old
used to be plaster, resurfaced with Pebbletech 10 yr ago
Chlorine system
Pentair 420 cartridge filter
1 hp pump
¾ hp booster pump
Letro Legend pool sweep

double-tested with new Taylor TF-100

pH > 8.2

FC 2.5 ppm
CC 1.0 ppm
TC 3.5 ppm

CH 625

TA 240

CYA >>100 (150?)

Your recommendations respectfully requested.
 
Welcome to the forum. Bad news is, being in Cali, the first recommendation is to replace half your water then retest your cya level. Then your PH needs to drop into the mid 7 range. The fresh refill may take care of part of that. You're still in need of Slamming the pool with a CC of 1.0 and the FC level has been maintianed FAAAAAAAAAAR too low for the cya level. See the chlorine/cya chart in pool school after replacing the water.

What exactly do you mean by a "chlorine system"?
 
Welcome to TFP !
If you do a dilution test for your CYA you'll get a better handle on where its at. Use half tap water, half pool water for the test. Then take your result X2. If your diluted test is say 80 then your CYA level is 160. You can then use Pool Math to see how much water needs to be replaced to lower your CYA level.
How does your water look ? ?
 
Woody has addressed the primary thing you need to worry about, getting the chlorine level up With 100+ CYA you need a lot more chlorine int he pool. Don't believe the pool stores when they tell you to keep it between 2 - 5. Believe the FC/CYA chart.

As Jeff said a diluted test is the way to go. 100 is the limit of the CYA test, so you have to do a diluted test. While the full instructions are in the Pool School, here is the short version. Mix 50% pool water with 50% tap water. Use this mixed sample as your test water. If still at a 100 you will need to dilute more. Here is a great chart by JamesW to explain dilution rates and what you multiply the results by to get an approximation of your CYA level.

Pool water......Tap or distilled water.........Multiply result by

....1...................1................................2
....1...................2................................3
....1...................4................................5

You need muratic acid to get that pH down.
 
Thanks to woodyp, pwrstrk, and tim5055 for your prompt and expert guidance.

woodyp asked "What exactly do you mean by a 'chlorine system?'" -- sorry to be unclear: I meant we use chlorine rather than salt (but it's all done manually, no automatic chlorinator etc.).

I will replace half the water and give results the dilution CYA test after refill.

Thanks and best!
 
Your should do the dilution test before you replace water. Right now your at the limit of the CYA test. The dilution test is for when your initial CYA test reads 100. It will give a better idea as to where the CYA level is and how much water needs to be replaced. ?
 
Misha T said:
woodyp asked "What exactly do you mean by a 'chlorine system?'" -- sorry to be unclear: I meant we use chlorine rather than salt (but it's all done manually, no automatic chlorinator etc.).

Thanks and best!
Click to expand...

There are many forms of chlorine. Are you using tabs, pucks, powder or liquid bleach? Solid forms of chlorine (tabs, pucks and powder) always add something that can build up to a level that is too high. Solid forms of chlorine add either stabilizer (aka CYA) or calcuim (which will rise CH).
 
Misha T said:
Also I forgot to answer your question, "How does your water look ?"
Answer: it looks cloudy.
Click to expand...
Cloudy water is generally a symptom of improper chemicals. In your case I'm betting the low chlorine levels are letting things begin to grow in the water. You need to get the chlorine level up now or you will not only be fighting high CYA but a full blown algae bloom.

Assuming your FC is still 2.5 you need to add over 4 bottles (121oz) of 8.25% bleach to get it up to at least 14. Great Value from WalMart will work. Aslo, please remember that chlorine is a consumable item and must be tested and added daily to keep it at the target level for your CYA level.

You also need about 50oz 31% muratic acid. You will find it in the paint department at Lowes, blue label (not green label "low fume")

Muratic Acid has a strong vapor and is not really good for the lungs so avoid holding the open bottle where you are going to breath the fumes. Here is how I add it: Pick a spot over a return in the deep end of the pool; kneel down there so you are stable; Splash water on teh pool deck and set the bottle on this spot; Open the bottle and partially submerge the bottle in the pool; tilt the bottle and pour acid into pool slowly; Recap bottle while it is still in the water and then use pool water to clear any drips off the side of the bottle. I never "measure" my acid, but guesstimate from the amount needed to what I add. if I needed 50oz and it was a 100oz bottle i know to add about half. In my mind measuring is just an additional step where you can have an accident.

Chlorine I add while walking around the pool trying to pour in front of the returns to mix it as quickly as possible. It is not a race, so pour slowly to avoid splashing.

With the pump running add one of them and wait at leas 30 minutes before adding the other.

Once you get the pH and chlorine stable - it is time to attack the CYA.
 
Wow! Such great and well-informed help!!

In answer to kindc: I will be using liquid chlorine (previously followed bum advice from L***** ' * and was using tabs & powder building up the CYA and CH).

Did the PoolMath and plan to re-fill about 3/4 of the pool with fresh water tomorrow because the CYA is so outrageous and the CH is also high.

Sound about right?
 

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Yep. Use pool math to figure out how much liquid chlorine to add so you get some chlorine in there. This is going to go green if you don't get your FC up. Your on the verge now. Also get your PH down into the low 7's. I would do this first then add your chlorine. Then do your water replacement. Did you do your dilution test yet and what are the results ?
Keep us posted on how things are going. ?
 
my values a few days ago were

date pH FC CC TC CH TA CYA
10/18 >8.2 1.0 0.5 1.5 650 220 140



To lower the CYA I intended to drain about 75% of the water,

but I fell asleep and drained about 85%.

Even with the refill the CYA remained incredibly high (carefully measured over and over, including dilution tests, because I couldn’t believe the results):

date pH FC CC TC CH TA CYA
10/21 >8.2 0.5 0.5 1.0 150 70 95

Because the water here in Fresno can be weird (instead of a river, aquaduct or river it comes from a bunch of pumped groundwater wells) I tested the tap water.

date pH FC CC TC CH TA CYA
10/21 >>8.2 1.5 0.5 2.0 25 30 0 tapwater

I cannot figure out how come the CYA would remain so high with the almost total refill.

I decided to at least lower the pH so I added one gallon Muriatic Acid (14.5%).

about 4 hours later I added 2 gallons liquid Chlorine (10%).

and unfortunately I mistook a bottle of Muriatic Acid for liquid Chlorine and added another gallon of Muriatic Acid (2 gallons total) and lowered my pH too far

today I added one more gallon liquid Chlorine and today my values are

date pH FC CC TC CH TA CYA
10/23 7.0 4 .5 4.5 175 60 90

Do I need to start over with the refill?
 
Could you please list your test results like this with a space in between the parameter and the result. That's very hard to read the way you have it set up. Honestly I only tried to read the the first set of test results. This way it's easier for everybody to see your results. Thanks ! ?
FC
CC
PH
TA
CH
CYA
 
Not hardly possible that your CYA is still at 90 with an 85% drain. I'm suspecting a testing error here. You didn't do the dilution test after draining and refilling and then double the result did you?
 
Replaced 85% and cya still at 95 huh.
Several thoughts

First I suspect your cya was well over 140 to start. With your cya and ch so high I suspect there have been years of using whatever tab was on sale that month.


What to do now?

If you can I'd drain about 60%. In Fresno you want cya of around 40. Maybe 50 or 60 if you have no shade at all on the pool. I would aim for 40 and after next summer increase it if you Burn too much chlorine

You can then retest and balance the water.

If you can 't drain you can manage a pool with cya of 90 but it is difficult and requires large amounts of chlorine.
 
Thanks to all for your help so far. I have changed my signature to give the important information and I am trying to format the data better.

I decided to wipe the slate clean and I did a total drain and refill, just completed.

Here is where the water is right now:

FC 0.0
CC 0.0
pH 7.6
TA 130
CH 125
CYA 0

What's next please?
 
Add some CYA and bleach.

I'd bring the Ph down closer to 7.2 first.
Shoot for a CYA of 30 or 40 starting out unless you know others in your area are running more.
Add the correct amount of bleach for the TARGET CYA level you are shooting for even though you won't be able to test it for a week.
 

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