Why are there white form at water line ?

[Kevindong]

Any cause to that ?

number
FC 4.5
cc 0
PH 8+. It has been raining for couple days
TA 100
CH 300
CyA 25
added 20 oz acid to bring down ph. To 7.5
but what caused it ? Ph was 7.6 two days ago and there was already white form like that

 

[Patrick_B]

The 8+ pH, 100 TA, and 300 CH are enough to contribute to some waterline scale..which is what it looks like. How long have these numbers been true, and how often do you find the pH above 8.0? A little rain or even quite a bit should not increase your pH all that much. This is less likely to happen when pH, and TA are kept lower consistently. Without knowing more, those are my thoughts.

 

[JoyfulNoise]

A heavy duty sponge or tampico brush and some dilute muriatic acid (wear gloves and eye protection!!) will take that right off. Patrick_B is quite right, that's standard waterline scale and it can develop even in balanced water because there is constant evaporation at the tile/water interface that changes the chemistry slightly in that region. Pools that fill up and drain down a lot with rain will also see that happen because the evaporating water line leaves behind a film of salts and calcium. That's why it is always important to maintain a consistent water level or else you will get the "bath tub ring".

 

[Kevindong]

Ph has been raising consistently. And I had to add acid to bring it down last two week. And it has been stable at 7.6 for almost a week last week and heavy rain hit two days ago and stop today. So I did some text right after the back. And ph raised to 8+. Is my TA too high at 100 so. Ph is kind of hard to maintain ? And what about CH ? Acorrding to pool school info. My CH is at the range.

 

[Texas Splash]

Your CH is in a good range. Your TA is not that bad either at 100, although you could lower it a little more (i.e. 60-70) by following the TFP Pool School - Lower Total Alkalinity page. Lowering the TA a little might help keep the pH from rising too fast. Most important right now is keeping the pH below 7.8. Ideal pH would be right around 7.5-7.6. Remember that pH has a tendency to rise in new pools (new plaster), pools with high TA levels, and aeration. If your spa has a spillover and runs a lot, you might consider reducing the amount of time the spa spills-over. Not sure why your pH decide to climb recently, but continue to watch the pH carefully and consistently to ensure pH stays below 7.8 and you should do fine with calcium/scale control.

 

[Kevindong]

Thanks. I will just lower the TA and watch carefully with ph.

 

[Kevindong]

Your CH is in a good range. Your TA is not that bad either at 100, although you could lower it a little more (i.e. 60-70) by following the TFP Pool School - Lower Total Alkalinity page. Lowering the TA a little might help keep the pH from rising too fast. Most important right now is keeping the pH below 7.8. Ideal pH would be right around 7.5-7.6. Remember that pH has a tendency to rise in new pools (new plaster), pools with high TA levels, and aeration. If your spa has a spillover and runs a lot, you might consider reducing the amount of time the spa spills-over. Not sure why your pH decide to climb recently, but continue to watch the pH carefully and consistently to ensure pH stays below 7.8 and you should do fine with calcium/scale control.

One more question though. How do I add liquid Murcia acid ? What I have done was get a bucket of the water from pool and add acid to that and pool that mixture around the pool ? Or do I just pour that directly to the pool ? And my pool is kind of spill over from spa. And main return are from the spa. So should I just pour acid directly to that middle of the spa ?

 

[Texas Splash]

You can pour acid directly to the pool. Always best to do it with the pump on high to ensure good water movement as you "slowly" pour the MA near a return jet(s). Be aware of the wind direction to avoid fumes to the nose & eyes. Not so sure I'd pour into the spa (shallow) or try to get too close to the spillover since you don't want the MA to have any chance of splashing back onto you. Usually we're only talking about a cup or two of acid at a time, so if you have no returns at all (other than the spillover) maybe pour slowly in the deep end and brush that area right away to ensure the acid is diluted and moved around. Regardless of which method you end-up trying, the key points are avoiding fumes/direct skin contact, and not letting the acid accumulate in any one area out of concern for the pool surface. Once the acid gets moving in the water though, you're in good shape.

 

[Kevindong]

You can pour acid directly to the pool. Always best to do it with the pump on high to ensure good water movement as you "slowly" pour the MA near a return jet(s). Be aware of the wind direction to avoid fumes to the nose & eyes. Not so sure I'd pour into the spa (shallow) or try to get too close to the spillover since you don't want the MA to have any chance of splashing back onto you. Usually we're only talking about a cup or two of acid at a time, so if you have no returns at all (other than the spillover) maybe pour slowly in the deep end and brush that area right away to ensure the acid is diluted and moved around. Regardless of which method you end-up trying, the key points are avoiding fumes/direct skin contact, and not letting the acid accumulate in any one area out of concern for the pool surface. Once the acid gets moving in the water though, you're in good shape.

Still need to play around with this new VS pump I just got. Maybe I need to turn that pump on high for vacuumed and adding chemical as well.. And I will turn on the pool return more for that. I don't know why though my TA is still 100 since I have been adding quit a bit of acid to the pool lately.? Judging by the size of my pool I was actually expecting at least 10 pm drop on TA. But it actually holding up still 100 since I have been using one gallon of acid in two weeks.
I heard people said. In order to drop the TA. I have to pour acid in one spot. Like in front of the return jet at deep end. Pouring mixture acid around the pool is for Lowing down Ph only ?

 

[YippeeSkippy]

No, the Muriatic Acid (MA) will lower the pH and TA. if all you want to do is lower your TA you can take the pH down to about 7.2 and it will drag the TA down too. And then use aeration to bring just the pH back up.

If your TA remains high it will contribute to your pH staying or returning up higher again too.

Have you read this: Pool School - Lower Total Alkalinity
and this- ABCs of Pool Water Chemistry These two articles may help you understand better

Yippee

 

[Kevindong]

Okay. I have read that. So ph has to go down till 7.2 in order to drag the TA down I got it now. Thanks