Question on Calcium Hardness with rock in the water/weeping waterfall

[SirMoose]

We have 2 rock weeping waterfalls that cross the waterline and sit in the water, each abouy 4 feet wide. pool is 1.5 years old and we are starting to see some white lines on the rock at or actually just above the waterline. Our calcium hardness is typically around 300-350. our fill water is quite hard. We've had lots of rain the past couple of weeks and calcium harness has dropped to 280.

Does anyone have insights into if the desired calcium hardness level should be shifted higher or lower based on having these rock weeping walls which sit in the water? Or on if having these rocks in the water makes the pool more sensitie to calcium levels? Or it could also be PH levels? we've alsp fought PH creep to 8.0-8.2 this summer with the heat, kids running the waterfall (have a plunge/waterfall section they like to use a lot as well), and being away from the pool this summer more than last year.

FA 2.5. FC 2.6. PH 7.8. TA 76. CYA 66. CH 279.

Yes, CYA is high. We've been moving that down since firing our pool guy who relied on too many tabs for sanitization.

Thanks!

 

[mknauss]

Welcome to the forum!
Most critical item is your low FC. Raise it now and follow the FC/CYA Levels. How are you testing your pool water chemistry?

The calcium scale you mention is likely the nature of the design you have. Evaporite scale is not possible to stop. You can just remove it occasionally.
I suggest you read through Pool Care Basics - Trouble Free Pool and even look at a few of our videos TFP-TV - Trouble Free Pool

 

[JoyfulNoise]

Natural stones are much more sensitive to calcium scale just by their nature. Many have significant amounts of calcium bearing minerals in them to begin with. Just look at the current state of Lake Powell or Lake Mead to see how water can deposit scale on natural stone

Simply scrape off what is loose and leave the rest. The pool water is going to change the color and texture of the submerged portion of the stone over time so there will always be the appearance of a distinct water line on the stone. My stone waterfall is going on 10 years old and it has alway had a line at the water level.

 

[Flying Tivo]

You can try to seal the stone but its a never ending story.

 

[SirMoose]

Welcome to the forum!
Most critical item is your low FC. Raise it now and follow the FC/CYA Levels. How are you testing your pool water chemistry?

The calcium scale you mention is likely the nature of the design you have. Evaporite scale is not possible to stop. You can just remove it occasionally.
I suggest you read through Pool Care Basics - Trouble Free Pool and even look at a few of our videos TFP-TV - Trouble Free Pool

Thanks, yes been reading the articles and trying to keep FC up. FC does seem to jump down quickly at times - either due to heavy rainfall or limitation of the FC dropper test i have (unlike Spinal Tap this one only goes to 3).

For testing, have been using up the last of the pool company dropper test and supplementing with a test at Leslie's 1x/week. Only been adding liquid Chlorine, Muriatic Acid, and a bit of Sodium Bicarb here and there since June - been trouble free aside from dumping water to lower CYa.

Was worried about the dropper fluids being old but seems to track quite well with Leslie's. Just recieved my TF-100 on Thu, looking forward to breaking that out this weekend.

Thanks for taking the time to respond and help out. Much appreciated!

 

[mknauss]

Use the TF100. Post results from that.

 

[SirMoose]

You can try to seal the stone but its a never ending story.

Yes our contractor said the same - fought it onn his own pool for a while before giving up.

Use the TF100. Post results from that.

I ran the TF tests a couple of times, got the same results (which are a bit different than Leslies for TA, CH, and CYA):

FC 1.5. CC 0 TC 1.5
TA 90. CH 325-350. CYA ~50.
PH was 8.2, maybe a bit higher. is there a test to get a more accurate reading for this - or just add muriatic, retest, and go from there? is there a maximum of muriatic to add at any one time? added 28 oz (pool math says that will drop it 0.4 for our pool)

Pool water is clear, no algae or anything when brushing the walls. got another inch of rain today. it is a chlorine pool, 18.5 kGal, pebble tech/plaster.

Thanks again for the insight/ guidance!

 

[mknauss]

is there a test to get a more accurate reading for this - or just add muriatic, retest, and go from there?

Exactly. You can get a pH probe. But in reality, you only need to know that the pH is between 7.2 and 7.8.

is there a maximum of muriatic to add at any one time? added 28 oz (pool math says that will drop it 0.4 for our pool)

pH adjustments should be in 0.3 to 0.4 amounts. So whatever amount of acid that takes, is good. Add, circulate pool for 30 minutes, test pH again, and adjust if necessary.

Your FC is very low. See FC/CYA Levels

 

[SirMoose]

Exactly. You can get a pH probe. But in reality, you only need to know that the pH is between 7.2 and 7.8.

pH adjustments should be in 0.3 to 0.4 amounts. So whatever amount of acid that takes, is good. Add, circulate pool for 30 minutes, test pH again, and adjust if necessary.

Your FC is very low. See FC/CYA Levels

yep copy. fc is much too low. was looking to get ph down first then take care of that this evening. that's the right order or does it not matter much?

looking at CSI in pool math, it's at 0.64 with the tf100 numbers above, but if i bring the ph down that should nip it. wonder how long I've had higher than thought ph. neither here nor there, got the tf kit now!

thanks for the help!

 

[mknauss]

does it not matter much?

Does not matter. Add them a few minutes apart at a return with the pump running.