Damaging plaster in my pool?

[BurgDweller]

Hello all,

These are the numbers below I have been maintaining for the past several years in my pool. My first year maintaining the pool on my own using the trouble free method, I was in a constant battle to keep the TA within the recommended levels. I felt I was wasting a lot of $$ on baking soda and muriatic acid. I was constantly adding baking soda to increase the TA then adding MA to lower my pH. Out of exhaustion, I finally let my TA bottom out to 40 which it has been at for about 3 years now and I have not added any baking soda since. I usually add about 6-12 ounces of MA once a week. I have had no algae outbreak and my water is crystal clear blue. Am I causing serious damage to my plaster? It feels like my pool surface is getting more rough on the feet.

FC 8
CYA 40-50 range
pH 7.5
TA 40
CH 220

 

[jblizzle]

Yup, that would be damaging your plaster.

Enter all your numbers in PoolMath and check out the CSI calculated on the bottom.
You need to either increase your CH or your TA or your pH or some combination.

How are you adding chlorine? Usually the pH and TA will only drop if you are feeding the pool a diet of trichlor tablets or using dichlor powders.

 

[Richard320]

My vote is that you are etching the plaster

Plugging those numbers into PoolMath and calling the temperature 85 shows -.58 CSI. Put some salt into the equation (Bleach breaks down into salt) and it goes even further negative. When the pH climbs, you're still skating awful close to the edge. And you say it feels rough. Pitted, maybe? Because you probably are etching the plaster.

If you don't want to raise TA, then you'll need to raise CH. If you want to fix it fast, add Calcium Increaser. If you're more patient, chlorinate with Cal-hypo. Poolmath can tell you the dose just like it does with bleach.

 

[BurgDweller]

I am adding liquid chlorine. Never used tablets or dichlor powders. My pH rises in my pool. I have never had my pH lower on its own.

- - - Updated - - -

So raising the TA to 60 and the CH to 280 brings the CSI to -0.29. Is that a good place to be?

 

[triptyx]

That's much better, yes. But bear in mind water temperature also plays a role and you may end up in trouble when your pool cools down for the winter at the end of the season.

What is the pH, TA, and CH of your fill water?

 

[BurgDweller]

That's much better, yes. But bear in mind water temperature also plays a role and you may end up in trouble when your pool cools down for the winter at the end of the season.

What is the pH, TA, and CH of your fill water?

I can check the pH, TA and CH of my fill water tomorrow. That is something I never thought to check. Why would water temperature change in the winter cause trouble? Thanks!!!

 

[jblizzle]

Play with PoolMath and you can see how different parameters impact the CSI

 

[BurgDweller]

Thanks all for the assistance!! I got my CSI down to -0.01 by increasing the TA and CH. I will try to hang at that level for awhile and see how things go. Pool water always looked great but it looks even better now after the adjustments.