New plaster start up questions

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PoolCleanerMom

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Aug 26, 2009
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SF Bay Area (Lamorinda), CA
Our pool (about 18K rectangular IGP - previous homeowner had it fiberglassed about 15+ years ago but surface had become chipped and pool was leaking) has finally been replastered and filled, so now it's balancing time.

Current numbers:
FC 1ppm
pH ~ 8 (not sure exactly since 8 is the highest number on the watergram - I have the Taylor test kit)
TA 80
CH 80
(no CYA number yet - need to get more CYA reagent)

Have trichlor pucks in the dispenser and pump is running.

Brushed it once so far before testing water - didn't see any obvious dust getting kicked up (maybe b/c I'm used to seeing clouds of pollen dust that were in the pool before we had it drained and resurfaced) but there's the dust on the surface of the water - is this typical?

Is there a particular order in which I should be approaching the balancing - pH first? FC first? Calcium first?

And hubby is wondering how soon he can go swimming :)

Any other new-plaster-start-up advice welcome - thanks!

edited to add: PB doesn't do the chemistry, they provided a "Post Construction Pool Care" sheet that has fairly general guidelines (brush at least 2x/day until no longer visible plaster dust churned up, run filter at least 18 hrs/day for at least 1 week, make sure there's main drain suction to filter dust from suspension in water, monitor filter pressure and clean filter as needed, no swimming until there's no evidence of plaster dust in water and chemicals have been balanced)

I just checked the Pool School "new plaster start up" article - is the sequestrant necessary if we haven't had any prior metals issues with our municipal water supply?

Also - we had the main drain voided b/c of a leak somewhere in the line - will this cause a problem for filtering out the plaster dust? should we drop the manual vacuum hose into the deep end to get a bit of suction off the bottom of the pool in lieu of the main drain?
 
Well, I'd add the sequesterant. You don't want to take a chance with new plaster.

Your pH is too high. Test and adjust it back to the 7's each day, if necessary.

If you need to vac, use a vac head for a vinyl pool to prevent wheel marks.

The main things that need attention while the plaster is curing is to keep the PH under control and to brush the entire pool daily. Maintaining the pH normally requires adding acid daily.

Fresh plaster raises the pH, TA, and CH levels rapidly for the first three or four weeks, and then more slowly for up to a year. So, wait on adjusting. Using the trichlor pucks is perfect for now.
 
It really doesn't apply any time. The warning is to prevent you from lowering the pH too much.
If you're using the Pool Calc you can add pretty much as much as it says as long as you test and make sure you're not going too low on the pH. Of course, with a TA of 80, you'll need to keep an eye on the TA if you wind up adding a lot of acid.
 
Thanks, I *did* reset the muriatic conc. in PoolCalculator.

I added a total of one gallon of the 14.5% last night (about half of it at 7pm and then the other half at about 10 pm when I found the pH was still above 8) and this morning the pH was still above 8 (kinda magentaish) so I've added another half-gallon. Is there a general ballpark range of how many days I'll be needing to add large quantities of acid before the pH starts to stabilize?
 
thanks

one more question - starting to wonder if maybe my pH reagent needs to be replaced? I just tested our tap water with it and it's reading 8. I've had this test kit for about 1.5 years (bought it right after I joined the forum in Aug 2009) and still have the original pH reagents (have replaced the chlorine and CYA reagents several times but the rest are originals). Kit has been stored in the pool shed so it probably has on occasion exceeded the recommended 85F maximum storage temp.
 
Check to see if the reagent is staining the bottle it comes in. If it does stain the bottle then it is bad. I expect your PH to go up quickly, so nothing you have described suggests any problems with the PH test.
 

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JasonLion said:
Check to see if the reagent is staining the bottle it comes in. If it does stain the bottle then it is bad. I expect your PH to go up quickly, so nothing you have described suggests any problems with the PH test.
Click to expand...
Thanks for the tip. Bottle doesn't look stained and when I test water from the empty muriatic acid bottle floating in the pool, the result shows acidity so I think it's ok. Will try to get out to the pool store to get a new one within the next day or so though.

How soon after adding the acid should I test the water? I've been waiting at least an hour and so far every time I test, the result is still off-scale above 8 (so far have added 5 gallons of the 14.5% acid). I don't want to add too much acid too quickly - according to the pool calculator if my pH was around 8.2, I'd need 66 oz of 14.5% acid to bring it down to 7.5 and I'm adding almost twice that much at a time.

I expect that there's some variation in the amount of acid required to get a newly plastered pool into the target pH range, but it would be nice to have some ballpark idea of what's "normal" (if there is such a thing LOL) in terms of the number of gallons of acid one would expect to add over the first week or so that the plaster is curing
 
Re: New plaster start up questions - pH/TA balancing issues

additional question: I tested TA this morning and it's dropped to 50 so is this part of the reason I'm having difficulty getting the pH under control? And does that mean that I need to add baking soda first before adding more acid, or do I keep adding acid and then add baking soda? thanks!
 
There's no way to tell how much acid it's going to take because everybodies pool and fill water is different.

It's not unusual for it to take more acid then the Pool Calc says because pH is a hard calc to perform because so many things affect it. I.E. even low value borates affect it a lot. Just keep adjusting it and soon it'll start getting better.
 
Lower TA means the PH rises more quickly, but you don't need to use as much acid to get it back down. TA will rise along with the PH during the curing process, so I wouldn't raise TA very much if at all. Raising TA 10 or 20 won't hurt, however, it probably isn't important either.

Acid use varies a huge amount from pool to pool. One gallon a day is not unheard of, and that would be a gallon of full strength, which translates to over two gallons of the lower strength you are using.

You can measure the PH again half an hour with the pump running after adding acid.
 
Thanks for all the assistance

It's been exactly a week now since the pool was replastered and filling starte (filling was completed by midday friday). Been brushing daily and see a little bit of dust but it looks more like dirt dust (slightly gray-brown) than plaster dust. pH is about 8 when I check it first thing in the a.m. and then hovers around 7.6-7.8 after I add about 1/2 gal - 1 gal of the 14.5% MA (past few days have been adding 1/2 gal at a time instead of 1 gal at a time). TA is 60. FC is around 0.5-1.0 (still have just trichlor pucks in dispensers floating in the pool)

Weather is warm and hubby keeps asking when he can go swimming (water *looks* better than it ever has since we bought the house 5 years ago), so today's questions are:

1. based on what my pH values have been and not needing to add as much acid to get the pH under 8, am I close to being ready to let people into the pool?

2. do I need to add some bleach to up my FC or should I still be sticking to the "gradual addition by pucks" for the time being?

Thanks again!
 
Still need to test CYA - am out of CYA reagent and need to make a trip to friendly independent pool store. Have two puck dispensers in the pool now so any CYA is from them - would it be useful to put a few pucks in a skimmer sock directly in the skimmer too?

BTW some pics:
fresh plaster, view from shallow end
DSC_5689.jpg

fresh plaster - steps, new skimmer, equalizers, and vacuum port
DSC_5691.jpg

filled with sparkly new water
DSCF5007.jpg

new suction lines and 3 way valve - HUGE improvement over old line (http://i181.photobucket.com/albums/x232/chanjung4/swimming pool/DSCF3901.jpg ) and frozen ancient valve (http://i181.photobucket.com/albums/x232/chanjung4/swimming pool/DSCF4762.jpg )
DSCF5011.jpg


New suction line and skimmer seem to be having a very positive effect on overall circulation as well :goodjob:
 
Got test results from the independent pool supply store today when I went to pick up my CYA reagent. It's been about 10 days since the pool was filled. pH is stabilizing - requiring less acid to maintain below pH 8.
FC 0.7
pH 7.4
CYA 8
TA 27
CH 206

I added some bleach this evening and will start adding the CYA tomorrow. Should I start upping the TA now? It doesn't seem to be increasing a lot on its own.

(funny side note: I also bought a fresh bottle of FAS-DPD titrating reagent and one of the pool store employees commented "You've got the *serious* test kit - good for you!" TFP has been training me well :) )
 

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