Tiny White Bumps on my Pool Plaster

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Connie0101

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Aug 16, 2016
7
Houston Texas
I have tiny white bumps on the sides and benches of my new pool built in Feb 2016. I started noticing them around June. They are the size and shape of a pencil point and I can scrape most of them off. My calcium has always been high although my fill water has a CH of 130. When the CH reached over 500 in July, I drained some of the water and refilled it, bring the CH to 300. The CH began to rise almost immediately and is now at 520 and little white bumps are just getting worse. I talked to the builder and he says the problem is my chemistry and the fact that I am using a swg. I test the water daily, sometimes twice a day and have kept a log of every result and action. Even with my acid feeder set to 100%, I've had to add acid frequently and at the beginning I was adding extra acid almost daily. I am at my wit's end and ready to switch to chlorine.

Today's results:
FC 4.8
pH 7.8
TA 80
CH 520
CYA 60
Salt 3800
water temp 76
air temp 75

According to Leslie's Pool, my phosphates are high at 1000.

My questions are:
What is causing the tiny white dots?
Where is the high calcium coming from?
What do I need to do?

Thanks in advance,
Connie
 
It's not the SWG. Your PB is entirely full of beans on that score.

PBs/plasterers will almost always blame water chemistry. They have no interest whatsoever in honoring a warranty claim and failure of plaster is usually from poor water chemistry. Deficiencies in their work are hard to detect and nearly impossible to prove.

There's two possibilities. The most likely is a bit of scale forming and you can avoid it by lowering your pH target to about 7.6 and TA to around 60 or 70. Lowering TA will also reduce the frequency of acid additions, and probably get you down to just needing the acid feeder. Both those steps can be done due to their other benefits for your pool, and may reduce or eliminate the bumps over time.

The other possibility is calcium nodules forming as calcium escapes from behind the plaster. This happens when there are voids behind the plaster and it's very uncommon. I would forget about that until you try the methods mentioned above for a while. I wouldn't even mention it except that you mentioned very fast CH rise. The CH is more likely just coming from your fill water (followed by evaporation which leaves the newly introduced calcium behind). But CH rise from fill water should be relatively gradual.

Take a look at CSI in PoolMath and read a bit about it. Try keeping CSI between -0.1 and -0.3 for a while and see if that stops the bumps from re-forming.

There will be better experts than me come along as well and correct or clarify anything I've said that's wrong or misleading. The other thing is to avoid your pool builder. His suggestions are unlikely to be helpful, and could even be harmful. His main interest now is gathering information that might help him avoid any cost related to your pool.
 
Hello and welcome to TFP! :wave: Needsajet's recommendations are solid. PH will rise in a new pool for quite some time, and when combined with an elevated TA and/or CH level, scale is not too far behind. Something else you might consider (if available) is replenishing evaporated water with soft water if possible. Of course a residential water softener is not designed to supply large amounts at once, but with subtle water additions, it will help keep you from adding elevated CH supply water to your already elevated pool's CH. That's what I've been doing for a couple years now and it helps. Between that and the occasional Texas rains, my CH has dropped quite a bit over the year.

Adjust that TA and keep the pH lower to help with your CSI as recommended and you should see improvements over time. Continue to brush as well. Nice to have you with us.
 
I have found that my pool liked to stay between 60-70 TA with the pH at 7.6, but the pool builder and Leslie's both cautioned me that this would hurt my pool. So I add acid, and then I have to add baking soda almost daily, to keep TA above 80 and the pH correct. I talked to the plaster rep and he said I should be using a product called "Orenda SC-1000 Scale and Metal Control" and that would help. He also seemed surprised that I wasn't already using it. So, I've ordered that. Also, Leslie's freaked at the high phosphates and chlorine.

What is your opinion on this product?
Do I need to work on the phosphate issue?

Thanks again for all your advice.
 
Welcome to TFP!

There have been extensive discussions about whether or not to try to control phosphates. So far it has been a pretty resounding no. There are many, many folks here maintaining a successful pool who have never tested for phosphates, myself included. And many more with known high phosphates who also maintain their pools with no issues.

No need for scale and metal control at this point. What you were doing was the right thing to do. TA between 60 and 70 and pH between 7.5 and 7.8 is great. TA as low as 50 is fine in the majority of pools. If your pH starts bouncing around then you know your TA is too low and you need to raise it by 10 ppm.

Go back to what you were doing and your pool should settle in to a nice pH and TA balance around 50-60 TA and pH 7.6-7.8.
 
It can be confusing mixing pool $tore recommendations with TFPC so we recommend that you don't do so, because it usually doesn't work out well.

The most important problem arises because the pool industry doesn't recognize the importance of CYA. I believe this is intentional because the chem companies love selling trichlor and dichlor which contain CYA and cause pools to slide out of control, which leads to even more chemical sales. The CYA-FC relationship has been well understood for around 40 years, which is why I think the chem companies are doing this intentionally. At any rate, stick to TFPC recommendations and your pool will be safe both with respect to enough chlorine to prevent disease transfer and with the vast majority of the chlorine buffered by CYA so it's gentle on the skin and equipment. The levels are shown here: Pool School - Chlorine / CYA Chart

Pool $tores will tend to also either ignore the CH number, or expect your pool to be at the lower end of the safe pH range, which is why they think you need to raise TA. They're entirely wrong on that score. Scaling will be avoided and your plaster will last the longest using TFPC recommendations. In addition, the high CH will be less bothersome for you. Pool $tores expect pH to be lower because of the many people they have using pucks, tabs or powder for chlorine, which drive pH down, requiring pH raising chemical additions. Most people here almost never need to raise pH.

There's some excellent reference info here, but one that a lot of people find interesting is this one: Certified Pool Operator (CPO) training -- What is not taught
 
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