Slamming/high CYA

[mswarny]

Newbie here and I promise I'll fill in my pool particulars as soon as my pucker factor is lower.

20,000gal plaster pool
Sand filter
Recently moved in
Pool built in 85, previous owners not to keen on maintenance
Did the pool store stuff, shocked, algae fighter, HTH shock and swim, clarifier, just to have a couple of good swimming days with company. Ready to get to work, the TFP way.

This morning, Removed about 8" of water, added about 6", but CYA and CH no real change. Not enough, but man I feel guilty about watering my yard holding that huge blue backwash hose in my front yard for an hour.

Followed slam - added 12 gallons 8.75% bleach (Hence the pucker factor)

Measurements this morning before SLAM
pH 7.2
FC 9.5
CC 0.0
TA 190
CH 875
CYA 100 Checked multiple times, won't reach bottom of scale, verified at pool store

Followed SLAM - added 12 gallons 8.75% bleach (Hence the pucker factor)

6 hours later:
FC 47
CC 1.0

Added 2 more gallons of bleach to get to 56ppm an hour ago. Green is slowly turning to white as it should.

Now the questions:

1) If my CYA is high, it will retain the chlorine longer. If I kill the algae quickly, lets say at 40 ppm ( no reduction overnight - stays at 40 from pm to am), will it take forever for the chlorine to get to normal levels?
2) Since my CYA is high, I will not spend any more money on bleach (except for slam levels) that if it were at normal CYA and chlorine levels, correct?
3) So there is no real issue with a high CYA, as long as the chlorine is kept at 7-10 ppm ( as I recall)
4) I understand that the CH level is doable at 875, as long as I keep the pH in the 7.2 range correct?

I do plan on doing a lot of backwashing and adding of water to get both the CYA and CH levels down, but I can live with both, correct?

Lots of questions, but I love the site.

Thanks- Mark

 

[jblizzle]

Welcome to TFP!!!

If you never reached the 100ppm line for the CYA test, then your CYA is likely WAY over 100ppm. Do the CYA test again starting at 50/50 mix of pool and tap water, then regent, then double the results.

If the CYA is way above 100, then your FC levels are not going to be high enough to clear up the pool. Plus, when the FC > 10ppm, realize that your pH test is not valid.

To specifically answer your questions:
1. Doubtful that 40ppm is enough FC, but if somehow this worked, you can safely swim up to SLAM levels so does not matter much how long it takes to drop.
2. At higher CYA levels, you should actually need less bleach for maintenance, but you are going to suffer through the SLAM and be using up a LOT of reagents
3. IF your CYA is 100ppm, the you would need to keep the FC above 7ppm at all times and the pool should stay clean. Again note the pH test warning.
4. You will likely need to use a lot of acid to keep the pH that low, but that should keep calcium scaling at bay.

With the high CH and CYA, I would urge you to replace a lot of water and make you life much easier.

 

[mswarny]

Jason- thanks for the quick reply. I should have thought of that. You are correct, the CYA is more like 160-180. Off the charts.

I guess it's time to call the water company and get some sort of pool exemption on my sewer bill for 10,000 gallons.

 

[Casey]

Do something! It is outrageous to even consider dumping all of that chlorine to SLAM the pool. Once you get a series of drain/refills in and check after each one, we can help you take control. The CYA is just off the charts ridiculous. Welcome to TFP.

 

[duraleigh]

and get some sort of pool exemption on my sewer bill for 10,000 gallons

most places around the country charge 5-10 bucks /1000 gallons

 

[JVTrain]

most places around the country charge 5-10 bucks /1000 gallons

If I call my city office and tell them the water is going in the pool the $6 sewage charge per 1000 gallons gets waived and then the cost is $1.60 per 1000 gallons...

At that rate, I could switch to trichlor pucks... but I won't.

 

[Kiss4aFrog]

Welcome to the forum.
Suggest adding information about your pool and related equipment in your signature. By doing this, it will automatically appear in all your posts so you do not have to re-enter it each time. If you have a SWG, please include those letters in your signature so it stands out as the advice for SWG vs. non-SWG is often different
1. The size of your pool in gallons
2. If your pool is an AG (above ground) or IG (in ground)
3. If it's IG, tell us if it's vinyl, plaster/pebble, or fiberglass
4. The type of filter you have (sand, DE, cartridge) and, if you know, the size, model number or flow rate of the filter.
5. If you know, please tell us the size pump in HP. Also mention if is it a two speed or variable speed pump.
6. Date of pool build/install, particularly important if less then a year old.
7. Other significant accessories or options, such as a spa , SWG, or cleaner