Help with balancing after new plaster

unsrek1

Member
Jul 14, 2010
22
Reno, Nevada
My 25K in-ground pool was re-plastered with Pebble Fina last Friday, and I'm having trouble balancing the water. Plus I saw in one topic here that a freshly plastered pool might require different recommended levels? At any rate my first obstacle is the high PH. I've added 1.5 gallons of muriatic acid over the course of the last several days, and PH is still off the chart. (I used the 'green' muriatic acid first, and now I'm using the nasty full-strength stuff.) Tough to gauge how much more to put in when every reading is too high to measure. Any suggestions?
Next I'm going to need some CYA for this weekend's pool party, but I see that the solid should be added when back-flushing isn't necessary. But my fresh plaster requires constant brushing and back-flushing. How do I get around those conflicting requirements?
At first reading my TA was 60, and I was going to boost that once I get PH under control. Calcium is also low - about 50 - so I was going to start adding that too. I've been using a combination of bleach and tri-chlor tablets for chlorination - partly to get the CYA up a little with the tablets because the pool is exposed to direct sunlight much of the day.
Any advice appreciated.
 

svenpup

LifeTime Supporter
Nov 18, 2009
835
Sacramento, CA
unsrek1 said:
Tough to gauge how much more to put in when every reading is too high to measure. Any suggestions?
Figure how much you need to get from max for your test to target, and repeat as necessary. Don't worry if it seems like you are adding too much. Its isn't like all this acid is "building up" and causing "acid water". All the acid you add is offset by the high pH from the plaster.


unsrek1 said:
Next I'm going to need some CYA for this weekend's pool party, but I see that the solid should be added when back-flushing isn't necessary. But my fresh plaster requires constant brushing and back-flushing. How do I get around those conflicting requirements?
Add the CYA in an old sock in front of a return (as opposed to in the skimmer). This way you aren't losing as much when you backwash.


unsrek1 said:
Calcium is also low - about 50 - so I was going to start adding that too.
From another post:
JasonLion said:
With fresh plaster, you don't want to adjust the CH level for the first three or four weeks. PH, TA, and CH will all be rising rapidly during the first month. If you raise CH too early, it will go up further and end up too high.
 

benavidescj

LifeTime Supporter
Apr 27, 2010
431
Fleming Island, FL
The easiest way to determine how much acid to add is to use the acid demand in a titration test kit. If you are using the K-2006 (the TF100 does not have it), you add acid demand drops into the pH solution and count the number of drops it took to get to the desired pH. The you look up how many drops vs the size of your pool and the manual will tell you how much muriatic acid to add. You should try to get this under control because a high pH is not good for the plaster especially a fresh, still curing one.
 

unsrek1

Member
Jul 14, 2010
22
Reno, Nevada
Thanks for the rapid responses. Sounds like I should not mess with TA or Calcium for the time being as they will be rising by themselves as the plaster cures.
I'll look into a titration test kit to determine my acid demand. Would it be easier, better, safer to use dry acid from the pool store rather than muriatic acid since I may be doing this a lot for a while?
 

svenpup

LifeTime Supporter
Nov 18, 2009
835
Sacramento, CA
unsrek1 said:
...Would it be easier, better, safer to use dry acid from the pool store rather than muriatic acid since I may be doing this a lot for a while?
Easier-maybe, better-nope, safer-maybe. Dry acid adds sulpher, which you don't really want, and is more expensive.

Muriatic acid is fine, as long as you take a little precaution. Wear eye protection when you use it. Pour slowly in front of a return with the pump on, or better yet dilute it into a 5 gallon pail 3/4 full of water before adding it to the pool (also in front of a return with the pump on).
 

unsrek1

Member
Jul 14, 2010
22
Reno, Nevada
How about if I put the sock with the CYA in it into the debris net on my Polaris sweep? The acid wouldn't damage the net, would it? (Just haven't figured out the logistics of hanging a sock in front of a return.)
 

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