Massive scale problem last spring. What to do this fall?

[Bart]

This is my second full year of having a new pool. The first spring everything went fine and looked good when the pool was opened. The second spring (7 months ago) I had a massive scale problem on the walls and bottom. I was able to knock it back with two no-drain acid washes, but I want to eliminate a repeat performace this year.

The pool builder has done all the openings and closings and I suspect they screwed up on the closing last fall which led to my scale problem.

What do I need to have done during this closing to prevent another scale build up? Is it just a simple matter of ensuring they actually put scale inhibitor in the water this year?

THANKS!

PS - gunite pool, SWG, solar heat

 

[Bama Rambler]

Re: Massive scale problem last spring. What to do this fall

The best thing you can do is post a full set of test results.
Once you have a full set you can adjust the levels to help prevent scaling over the winter.
You should also check the levels a couple times over the winter just to make sure something hasn't gotten completely out of whack.

 

[Richard320]

Re: Massive scale problem last spring. What to do this fall

I agree. Test results would tell us a lot.

If, for instance, your CH is into 4 digits, some water replacement is called for. Likewise, super high TA is going to cause pH to rise, which will encourage scale formation.

Your location also helps. Where I live, it never freezes. We hardly even see frost. So, while the water is too cold to swim, it still gets maintained year round.

 

[Bart]

Re: Massive scale problem last spring. What to do this fall

Here you go:

FC 2.5
ph 7.5
T/A 100
CH 540
CYA 65

I'm in northern Virginia and in my location, we get down into the single digits every year and have weeks of temps below freezing.

Thanks!

 

[Richard320]

Re: Massive scale problem last spring. What to do this fall

Here you go:

FC 2.5
ph 7.5
T/A 100
CH 540
CYA 65

I'm in northern Virginia and in my location, we get down into the single digits every year and have weeks of temps below freezing.

Thanks!

It looks like CSI is neutral. You could lower TA a little and push pH down to 7.2/7.3 to get it slightly negative. That should give you a little insurance.

Also note FC is too low for your CYA.

Your pool is almost like a living thing; if it's at peak health it can withstand a lot more stress and infection than one that's only marginal.

 

[duraleigh]

Re: Massive scale problem last spring. What to do this fall

Adding a bit, I agree to keep your pH below 7.5 (7.2 would be nice) right up until the time you close.

A contributor to you scaling issue is CH is a bit high @ 540 but I suspect you have had pH over 8.0 for extended periods of time in the past........keep your pH low.

What is the CH of your fill water? YOu could perhaps benefit from a partial drain to lower the CH in your pool if your fill water is low.

 

[Bama Rambler]

Re: Massive scale problem last spring. What to do this fall

Just agreeing with the rest. I'd knock that TA down to about 80 ppm, and if your fill water is low in CH I might consider replacing enough water to get the CH to about 500 or a little less.

 

[Bart]

Re: Massive scale problem last spring. What to do this fall

Thanks folks! I try to keep my ph down at 7.2 to combat the regular bit of scale that I see during the year. That 7.5 number was before adding Muriatic Acid to keep it low.

Should the pool company be adding some chemicals like a scale inhibitor?

 

[duraleigh]

Re: Massive scale problem last spring. What to do this fall

Should the pool company be adding some chemicals like a scale inhibitor?

There's no need if you follow the guidelines above and in pool school. Additionally, it maqy not work if you let your parameters get away from you.

In short, control scale by controlling pH, CH and TA and you will have no need to rely on something that may or may not work.

 

[Bart]

Re: Massive scale problem last spring. What to do this fall

Thanks again folks!

I have about 3 weeks to bring my t/A down before the closing. Should I shoot for the lower end of the scale?

 

[Bama Rambler]

Re: Massive scale problem last spring. What to do this fall

Given that you've had a scaling issue in the past I'd would shoot for a TA of about 70. You might even go to 60 but you don't want to get too low.

 

[Bart]

Re: Massive scale problem last spring. What to do this fall

Excellent, thanks!!!