Draining for CYA Dilution

[fldon]

I've been trying to bring down my CYA level from approx 130 per the pool store. I've drained about one foot on four occasions. My level is still high at 100. I just noticed on the The Pool Calculator this Note: It can take solid stabilizer up to a week to dissolve. It will also lower your pH.
Does this mean that I should wait at least one week after draining each time (I did not)?

 

[Butterfly]

No, the PoolCalculator is just letting you know that it can take up to a week for the CYA to register on a test AFTER you ADD it to your pool. You are removing it, not adding it.

Welcome to the forum

 

[fldon]

Thanks for the speedy reply. Draining is sure getting old, fast - this CYA problem is a PITA!

 

[Butterfly]

Thanks for the speedy reply. Draining is sure getting old, fast - this CYA problem is a PITA!

You're welcome and, Yep, having an overstabilized pool is the reason lots of folks hit the net and find TFP!

If you'd like more info, post the full set of water test results and tell us about your pool.

Is your fill water well or municipal?

What CYA level are your shooting for?

Is your pool in the sun all day long?

 

[jblizzle]

It takes more small water replacements to get down to the same level as 1 large water replacement since each subsequent replacement is removing water at a lower CYA level.

The quickest and least water method is one large change, but one needs to be careful of ground water level and liner concerns.

Keep at it and you will get there ... and now have learned the dangers of CYA.

 

[fldon]

About a month ago, I noticed the algae was out of control, water murky green. I turned the tablet chlorinator on full which I have never done before. It couldn't even keep the pool chlorinated. After many dry cal-hypo shocks (at least 12 bags), Yellow Out, Green to Clean, I still had a problem. The water got clearer but the algae kept coming right back and I couldn't keep the chlorine level steady for more than a day or two. I had been told in the past that the CYA level was a problem (130) but I didn't want to drain the pool. I finally decided that I had no choice, so I drained a foot at a time, for a total of four times. Twelve (2.5gal) jugs later, the water is clear but it still eats up chorine fast. I just had the water tested - I added 2.5 gallons immediately.

FAC 0
TAC 0
CYA 100
CH 370
TA 110
Ph 7.6
Metals 0
TDS 1200
Phosphate 1500
Gal 15,000

 

[jblizzle]

Why did you choose to add 2.5 gallons? Did you calculate that was the appropriate dosage to reach your shock FC level?

Just curious if you are doing the shock process correctly or just dumping stuff into the pool on occasion.

If you are loosing FC quickly with a CYA of 100, you need to follow the Shocking Your Pool process outlined in Pool School.

However, it is going to be very difficult to accomplish this with a CYA up around 100. I would recommend a 50% water change to get to a manageable CYA level and then follow the article above.

It is also clear that you are currently relying on the pool store to do your testing. You will be much better off buying your own good Test Kit and doing the testing yourself to understand what your pool NEEDS and not what the pool store wants to sell you.

EDIT to add a link to a current test comparison between pool store and TF100 for reference:
my-test-vs-pool-store-test-t42519.html

 

[fldon]

I was just trying to keep it chlorinated ...

 

[jblizzle]

I did not intend to come off harsh, if I did.

We believe in proper testing and only putting into the pool what is required ... with the goal of having a clear pool and saving money. Odds are that the chlorine you added was not enough to get to shock level, let alone keep it there.

We would be happy to help you to do this, but it will take a little work from you to learn. You can start by reading ABC's of Pool Water Chemistry and additional articles in Pool School.

You can also help us by telling us about your pool (size type etc) and your equipment by adding it to your signature.

 

[duraleigh]

Adding to the good advice already given, bite the bullet and drain around 50% of your pool attempting to get the CYA down to 50ppm. Your pool will thank you and you will be able to keep it crystal clear the rest of the summer.

 

[fldon]

OK, more draining. I sure hope this will do the trick - I've never seen a pool eat chlorine like this before!