Lowering pH, a constant battle

[JLTXPRO]

I'm in the process of lowering my TA using Pool School's "Lower Total Alkalinity" article, to get my pH under control, since this has been an ongoing battle for a while now.

So my pH reading this morning was about 8.2, but it seemed that it was actually higher than that, since it is hard to tell what your actual pH is, once it gets out of range.
The Pool Math app recommened to add 2 quarts of Muriatic Acid, 31.45%, and I've added each quart about 1 hour apart from each other. I did it in 2 doses bc of safety reasons, and I have a small bucket to dilute it.

My questions are:
Should I keep testing every hour and add acid until I get to pH 7.2 ?
Is there a maximum dosage limit of muriatic acid within a 24 hours cycle? How much is it too much to add?
Once I reach the desired pH, then aerate? I have a spa blower that I can run to help with the aeration process.

 

[mknauss]

I've added each quart about 1 hour apart from each other. I did it in 2 doses bc of safety reasons, and I have a small bucket to dilute it.

No reason for that. Add the acid in a pencil size stream at a return with the pump running. Brush the area after. Do not use a bucket to dilute it, that adds a step that can end up spilling the acid.

Should I keep testing every hour and add acid until I get to pH 7.2 ?

Yes. 30 minutes of the pump running should be sufficient.

Is there a maximum dosage limit of muriatic acid within a 24 hours cycle? How much is it too much to add?

No. Test the pH. Brush the pool to be sure it is well mixed.

Once I reach the desired pH, then aerate? I have a spa blower that I can run to help with the aeration process.

Sure. Swimming is also good aeration.

 

[JLTXPRO]

No reason for that. Add the acid in a pencil size stream at a return with the pump running. Brush the area after. Do not use a bucket to dilute it, that adds a step that can end up spilling the acid.

Yes. 30 minutes of the pump running should be sufficient.

No. Test the pH. Brush the pool to be sure it is well mixed.

Sure. Swimming is also good aeration.

Thanks for your expert tutelage : ) . I'm very happy I found this forum... your advice and experience is truly invaluable. I was going nowhere with the pool store tests, and their "recommendations"

 

[JLTXPRO]

I've just found out that my CYA is currently at 50 ppm. But I have not done anything to lower it on purpose, which usually involves draining some water from the pool. I've been trying to lower my TA by adding MA, and aerating. and that's it as far as chemicals go. Has anyone experienced anything similar? in which the CYA level goes down when lowering for TA ?

 

[Jimrahbe]

J,

CYA will go down on its own if you quit adding it. I doubt the MA had any effect.

The rate CYA will go down is dependent on how much rain your get, how much fresh fill water you add, how much splash out, etc.

Thanks,

Jim R.

 

[V___25]

How were you testing your CYA? Your logs for 72 and 75 - are those pool store numbers? The CYA test from the TF100 or K2006 shouldn't be interpolated between the lines so it would be 80 in that test. If you've been relying on pool store numbers, those are wildly inaccurate. If you started doing your own testing, CYA is often the hardest for people and leads to testing errors.

CYA only leaves the water through draining and refilling and through evaporation over time. Any heavy rainfall lately? Heavy swimmer loads with lots of splashout?

 

[JLTXPRO]

How were you testing your CYA? Your logs for 72 and 75 - are those pool store numbers? The CYA test from the TF100 or K2006 shouldn't be interpolated between the lines so it would be 80 in that test. If you've been relying on pool store numbers, those are wildly inaccurate. If you started doing your own testing, CYA is often the hardest for people and leads to testing errors.

CYA only leaves the water through draining and refilling and through evaporation over time. Any heavy rainfall lately? Heavy swimmer loads with lots of splashout?

I'm using the TF100 kit, I was "averaging" the numbers on the tube, but now I know that it is a logarithmic scale and i have to fill each level until the black dot disappears.
so yeah, those readings are probably 80. But today it is 50 for sure.
So yeah, we've been using the pool quite a lot the last week, so it could be heavy splashing ... no rain lately, but we sure need it..

I've been battling for a while with what appears to be "mustard" algae, I brush it off, just to see it come back after a week, and I've been wanting to SLAM my pool.
Is it recommended to SLAM with CYA 50 ? or should I wait until it gets a bit lower?

 

[V___25]

You can SLAM with 50. Your FC level would be 20. In the Texas sun, I don't know that many people really let it get below 50 or else you'll be burning FC like no one's business.

 

[JLTXPRO]

Thanks to all,
While in the SLAMing process, is it safe to get into the water ? Since the FC levels are so high.
I want to clean/ scrub the light niches, scrub the walls, etc...

 

[mknauss]

You can safely swim in a pool as long as the FC is above the minimum and at or below SLAM level based on your CYA. You must also be able to see the bottom of the pool in the deep end of the pool.

 

[V___25]

Yes, it's safe to be in the water, with FC up to SLAM levels

 

[JLTXPRO]

You can safely swim in a pool as long as the FC is above the minimum and at or below SLAM level based on your CYA. You must also be able to see the bottom of the pool in the deep end of the pool.

Thanks,
on the Pool Math app, when I select the SLAM target FC = 20 (which is what the table shows for CYA = 50), it gives me a warning "that the target is outside the recommended range! "
Has anyone had that message show up on the app while trying to calculate the quantity of sanitizer to be used for SLAMing ?

 

[mknauss]

it gives me a warning "that the target is outside the recommended range! "

Correct. You are above the target. You are doing a SLAM, so of course you are above the normal maintenance level target FC.

Has anyone had that message show up on the app while trying to calculate the quantity of sanitizer to be used for SLAMing ?

Every time if in the SLAM process.

 

[JLTXPRO]

this morning CYA was 50 (tested twice just to make sure, since I thought it was kind of low), then this afternoon I added the recommended MA to reduce the pH to 7.2 - 7.5 and start the SLAM.

I went ahead and tested the pool water 2 hours after adding the MA, and found out that the CYA is 70 now.
Any ideas why the CYA jumped?
Do I need to let the pump run some more and get the MA all mixed really good?

 

[mknauss]

CYA does not change that fast. Testing error is the difference. Be sure the test is done in full sun, back to the sun, vial waist high.