Acid demand on new Pebble Tec plaster

Olga

Active member
Mar 24, 2016
30
Phoenix
Since our pool was built a few months ago, the techs have been coming by dumping jugs of acid into it every few days because the pH was rising unrelentingly. We installed an Intellichem system that is now working correctly. Our problem is that the acid tank is getting used up every two days trying to keep up with the acid demand of the pool.

The pH rises VERY quickly even when the pool is not running. For example, in 7 hours, with the pool NOT being used and NOT running, the pH went from 7.4 to 7.7. Because nothing was running, I'm surmising that the Pebble Tec surface must be leaching something that is driving up the pH. The pool builder says this is normal. Is it? Any ideas?

Second questions is, I read the startup instructions on this website, Pool Start Up Instructions for Pebble Tec and Pebble Sheen Pools - Modern Method Gunite - Houston Swimming Pool Services including Gunite, Pebble Tec, and Boulder Creation. They recommend pH 7.0-7.2 for the first month. What is the purpose of this? What happens if you don't do it?
 

pooldv

TFP Expert
Platinum Supporter
LifeTime Supporter
Moderator Emeritus
Aug 10, 2012
25,412
FL panhandle
PH rise is normal in new plaster pools. It takes about a year for new plaster to fully cure and PH rise to slow down. If you have waterfalls, bubblers or other water features they will also cause PH rise. Run them less to reduce PH rise. What is your TA? Lower TA, 60-80, will help slow down the PH rise. If your TA is high you can lower it following this process, Pool School - Lower Total Alkalinity

On that website, there are different methodologies for starting up new plaster. Where you hold your PH depends on the start up method your builder uses. More here, Pool School - Start-up New Plaster
 

dradam

LifeTime Supporter
Mar 10, 2013
214
Maryland
Pool Size
19000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-60
Not an expert, Just feeling your pain. Six weeks into a luna quartz wet edge finish and also using a lot of muriatic acid. My PB too says this is normal. I also have the intellichem system. I dilute the acid a little less, about 2 to 1 and I have set my system to dispense with a shorter mixing time, every 30 minutes 100ml. I find it easier to dial in using ml rather than ounces. I set my ph to 7.5. My pb did an acid start up for the first two weeks simply to expose the aggregate. My TA is about 110, will let it lower on its own with backwashes. I like the feel of borates and have found them helpful in softening ph swings as an added buffer, but if you add these now the PH will rise and need to be compensated. From what I see on this site the ph rise in fresh plaster is just part of the deal. Having the intellichem is making it much easier to manage for me.

Hope this helps.
 

Ocgasman

Bronze Supporter
Jun 10, 2015
150
Orange County, CA
I have a new pool also, about a couple months old. I also have a SWG and a negative edge wall which causes a fair amount of aeration. I'm also battling rising pH and have to add acid at least every 2-3 of days. Been using TFP method from day one. What has helped me was to lower TA to 60-80. This slowed my pH rise. Once my chemistry was dialed in, I added boric acid which helped a little. I'm being patient as I know the plaster is still curing and I have a SWG plus tons of aeration with the negative edge and laminars, not to mention kids splashing around. I think new plaster + SWG will just naturally increase pH at the beginning but hopefully the pool will eventually settle into a steady state. Good luck, I feel your pain.
 
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