Helping friend with a SLAM

[BigRobRN]

I'll try to be brief.
A fried of mine let their pool go over the winter. I'm picking up after some bad advice from the pool store that was given to them.
They have already shocked twice with stabilized shock, and are still running their SWCG.

18,000 gallon vinyl liner pool.
Sand filter.
So today we began with 10% Pool Chlorinating Liquid and got the FC level up to 28.
Turned off the SWCG. Brushed and vacuumed the pool. Backwashed the filter. Most of the green algae is gone, water is still terribly cloudy.

I know with such a high FC level, other results will be skewed so I don't know what they were prior.
Today I got a low pH off the chart low. Definitely way less than 7.0
Alkalinity of 50.
CYA of 70.

Should I wait until the SLAM is complete to adjust the pH or alkalinity?

 

[bobandsherry]

I'll try to be brief.
A fried of mine let their pool go over the winter. I'm picking up after some bad advice from the pool store that was given to them.
They have already shocked twice with stabilized shock, and are still running their SWCG.

18,000 gallon vinyl liner pool.
So today we began with 10% Pool Chlorinating Liquid and got the FC level up to 28.
Turned off the SWCG. Brushed and vacuumed the pool. Backwashed the filter. Most of the green algae is gone, water is still terribly cloudy.

I know with such a high FC level, other number will be skewed so I don't know what they were prior.
Today I got a low pH off the chart low. Definitely way less than 7.0
Alkalinity of 50.
CYA of 70.

Should I wait until the SLAM is complete to adjust the pH or alkalinity?

One of the first steps when starting SLAM is to bring pH to apporiate level. The reason is once you start SLAM and FC gets above 10, that test and other chemical tests are no longer reliable. You'll have to wait until FC is 10 or less to test your pH.

FYI, you don't need to turn off the SWG. It's only important to turn it off at night when doing OCLT.

Good luck...

 

[Richard320]

With a lot of circulation and a few backwashes, the pH is going to be different when you're done anyway, so why bother trying to fix it now only to have to redo it again in a couple days?

I doubt if it's acidic enough to etch the pump or the heater in a couple days, and if the liner is vinyl, there's no plaster to damage.

Maintain FC up there and keep the pool owner busy with the brush

By the way, this is priceless. It's so understated yet it says so much: "...after some bad advice from the pool store that was given to them." It wasn't given to them. They probably paid handsomely for that bad advice!

 

[Texas Splash]

Today I got a low pH off the chart low. Definitely way less than 7.0
Alkalinity of 50.

An elevated FC level should result in a higher pH level. In your case it's low, even with the bleach. You might consider adjusting the pH up a little in stages just so that you know it's back to the 7.0 (light orange) area. Not sure what equipment your friend has, but it makes me uncomfortable knowing the water is that acidic. Pool School - Recommended Pool Chemicals

SECOND THOUGHT - Richard believes it's okay, so let's go with that for now. Just monitor.

The TA can wait. Then simply make sure they follow the SLAM guidance. Good luck!

 

[BigRobRN]

With a lot of circulation and a few backwashes, the pH is going to be different when you're done anyway, so why bother trying to fix it now only to have to redo it again in a couple days?

I doubt if it's acidic enough to etch the pump or the heater in a couple days, and if the liner is vinyl, there's no plaster to damage.

Maintain FC up there and keep the pool owner busy with the brush

By the way, this is priceless. It's so understated yet it says so much: "...after some bad advice from the pool store that was given to them." It wasn't given to them. They probably paid handsomely for that bad advice!

Correct. She couldn't believe that 10% pool chlorinating liquid could do what all this other expensive stuff they are spending money on. And its been a good bit.

- - - Updated - - -

One of the first steps when starting SLAM is to bring pH to apporiate level. The reason is once you start SLAM and FC gets above 10, that test and other chemical tests are no longer reliable. You'll have to wait until FC is 10 or less to test your pH.

FYI, you don't need to turn off the SWG. It's only important to turn it off at night when doing OCLT.

Good luck...

Yes. I understand. I was introduced into this situation after corrective measures were taken.

- - - Updated - - -

An elevated FC level should result in a higher pH level. In your case it's low, even with the bleach. You might consider adjusting the pH up a little in stages just so that you know it's back to the 7.0 (light orange) area. Not sure what equipment your friend has, but it makes me uncomfortable knowing the water is that acidic. Pool School - Recommended Pool Chemicals

SECOND THOUGHT - Richard believes it's okay, so let's go with that for now. Just monitor.

The TA can wait. Then simply make sure they follow the SLAM guidance. Good luck!

Part of me really wants to get the pH up a little bit. I have some soda ash I keep on hand. The pH test is currently BRIGHT yellow.