Mystery Material Found after spring start up

JLFinATX · Mar 6, 2017

We are in Austin and the weather has been unseasonably warm, so I decided to warm the pool a bit a start the swim season. After doing a filter clean and testing chems (nothing was needed; all in great shape) I cranked up the run time to 12 hours a day. After a few days, this mysterious white stuff was found in the hot tub and on the tanning ledge by the bubbler. Not salt (yes I tasted it). It's flaky and doesn't dissolve. Calcium Hardness test was 220ppm. Any ideas? Should I be concerned? Thank you as always!

triptyx · Mar 6, 2017

Do you have a full set of test results to go along with the photo? A complete set will let us help you better.

samt · Mar 6, 2017

That looks like the same sediment that came out of my hot water heater when I flushed it. I thought it was calcium or lime.

YippeeSkippy · Mar 7, 2017

Grab some and pour a tiny bit of muriatic acid on it. If it bubbles it sounds like calcium.

Yippee :flower:

pooldv · Mar 7, 2017

My money is on calcium scale. If it is then we can work on that. Your water is probably similar to ours in that it has high scale potential and the alkalinity can run high, especially during drought when the water sits in the lakes and soaks it up. It isn't only high CH that contributes to scale. It is the combo of CH, TA and pH. In the right mix it can easily scale with CH at 220.

PoolMath will calculate your CSI after you enter all of your test results. Borate, salt, CYA and temp also impact the number. Keep your CSI between -0.3 and 0 to prevent scale in the pool and in your SWG cell. More here, Pool School - Calcium Scaling

JLFinATX · Mar 20, 2017

thank you for the great replies! We have been traveling so please pardon my delay in responding. Here are the stats from that day:
75 degrees outside
water heated to 77 degrees
salt 3300 (not sure why it's higher than when we left it in the fall - usually sits around 2950-3000)
output set to 50% for pool and 30% for spa on intellichlor
FC - almost zero - again not sure why with salt at 3300
cc - 0.2
pH - 7.6 - I was shocked - I feel like I have to add acid every time I test (every few weeks)
TA - 110
CH - 220
CYA - 80

I have backwashed the filter twice and am still getting the mineral deposits in the spa mostly but the Polaris is picking up some too. We've kept the water warm (around 85), except for last week when we turned off the heater while we were gone. Been running for about 10 hours a day, off at night. We've had mineral deposits on this one spot for months and it was always a mystery to me as no water touches this part of the pool wall.

An just now we noticed that the minerals seems to be leeching through the hairline cracks in the back wall of the pool

Please tell me that this is normal? Pool is right at a year old.

YippeeSkippy · Mar 20, 2017

You have efflorescence. That happens when water gets behind or into the wall and pushes the calcium or carbonate (whatever!) out and it dries on the surface. Do a search on it here and you'll find lots of threads discussing this and how to manage it. You may need to seal the walls better.

Yip :flower:

JLFinATX · Mar 20, 2017

My CSI is -0.26 and all is showing "balanced" with nothing needed.

pooldv said:
My money is on calcium scale. If it is then we can work on that. Your water is probably similar to ours in that it has high scale potential and the alkalinity can run high, especially during drought when the water sits in the lakes and soaks it up. It isn't only high CH that contributes to scale. It is the combo of CH, TA and pH. In the right mix it can easily scale with CH at 220.

PoolMath will calculate your CSI after you enter all of your test results. Borate, salt, CYA and temp also impact the number. Keep your CSI between -0.3 and 0 to prevent scale in the pool and in your SWG cell. More here, Pool School - Calcium Scaling

- - - Updated - - -

JLFinATX · Mar 20, 2017

OK - did some searching. The first picture I posted is the wall of the spa so water would be on the other side of the wall - although I don't like the idea of it seeping through - there is finished surfaces on both sides of that wall! Should I be worried?

The second picture is of the back wall of the pool. It doesn't have water on the other side, but does have pipes in the wall that lead to waterfalls that we never turn on. Again - should I be concerned that these are leaking inside the wall???? We did not finish our stone or the concrete wall with any type of sealer - guess that would help...

The main solution I am reading is to add diluted MA and wash it off. But I know for a fact that MA will damage concrete and I worry about my stone and grout. Has anyone tried it on these surfaces and what dilution would you recommend?

YippeeSkippy said:
You have efflorescence. That happens when water gets behind or into the wall and pushes the calcium or carbonate (whatever!) out and it dries on the surface. Do a search on it here and you'll find lots of threads discussing this and how to manage it. You may need to seal the walls better.

Yip