Chlorine and pH problems following missing stabilizer

[Cstaines]

Alright, just tested everything.

Water is clear with a very faint chlorine smell
Free chlorine 10.5 ppm
Combined chlorine 1.5 ppm
Cyanuric acid 300 ppm
pH 7.6
Alkalinity 320 ppm
Calcium Hardness 220 ppm

[PoolDoc]

Use muriatic acid to lower your pH to near 7.0, and just keep it there.
http://pool9.net/ma/

If you can aerate, that will not only help lower the TA, but will help remove some of the combined chlorine compounds that are forming.

Also, you need to add 6 gallon doses of PLAIN 8% bleach, each evening. With CYA = 300 ppm, a *normal* chlorine level is 15 ppm; 'shock' is 30 ppm or more. You'll need to get the chlorine level up above 20 ppm. Be sure to use the 10ml test sample with the K2006 (each drop = 0.5 ppm). Otherwise you'll use up your chlorine test drops too fast.

[Watermom]

You might hold the record for the highest CYA award. I can't remember another pool that we have had on here recently with a CYA level that high! Thank you, pool store!!

[Cstaines]

That sounds good. A question though, if the chlorine is well above 20 ppm in the evening, will we still have to add the 6 gallons of bleach that day?

[PoolDoc]

How much more chlorine you'll need to add, depends entirely on how much partially degraded CYA goo is left.

You can run a chlorine demand test to find you, if you like: http://pool9.net/bucket-demand/

[Cstaines]

Working on lowering the pH...about half way there. Getting some pretty foam with the aeration though. Should we be concerned about that? Chlorine seems to be holding high really well. Will try to fit a demand test in. Was still 27 ppm this morning.

Is it ok to start using our heater?

Is it ok to cover, or will the high chlorine eat the new solar cover?

Last, we were thinking about trying to start chipping away at the CYA with a 25% drain. We realize this will not have a profound immediate effect...but if we never start moving toward a healthier level, we may never get there. I would consider a larger drain, but I don't feel our pool could withstand it as we have a lot of ground water in our yard. I have yet to find an expert in this area of Pennsylvania who could help us. Thoughts?

[PoolDoc]

Getting some pretty foam with the aeration though. Should we be concerned about that?

It probably indicates some remaining unoxidized 'goo'; while this is the case, your water may be unpleasant to swim in. The solution to most of these issues is sustained high chlorine + sunlight.

Is it ok to start using our heater?

Not with these numbers:

pH 7.6
Alkalinity 320 ppm
Calcium Hardness 220 ppm

You'll scale up the inside of your heater core badly.

Is it ok to cover, or will the high chlorine eat the new solar cover?

No, you need the sunlight, to help break down the 'goo'. It won't hurt the pool to cover at night, or on rainy days. BUT, as that 'goo' is oxidized, it will tend to form volatile chlorinated by-products. These will evaporate . . . OR accumulated under the cover, if the pool is covered. These sorts of gases CAN damage plastics.

Last, we were thinking about trying to start chipping away at the CYA with a 25% drain.
I would consider a larger drain, but I don't feel our pool could withstand it as we have a lot of ground water in our yard.

I think you don't realize how many times you'd have to drain 1/4 of the pool in order to have an effect. The chart below shows the steps it would take to get below 300 ppm, draining in increments of 10% up to 25%:



However, if you want to go ahead and try, FIRST dig a post hole on the LOW side of the pool, as close to the pool as you can get. Dig it 1 foot deeper than you intend to drain the pool. (ie, drain 1ft; dig 2ft hole). Cover the hole and wait 24 hours. If it's dry, you're relatively safe. If not, don't!

Keep in mind that this does NOT guarantee that you won't damage your liner by draining!