White flakes blowing into pool from inflow pipes?!

[tomcolette]

We're new pool owners with a salt chorinator system. For the past few days I've noticed white flakes shooting from the inflow pipes when the filter starts. They're fragile and thin, like egg shell, shiney, and don't taste like salt. We've had low temps for our area at night lately, maybe in the 40s. Haven't used heater since Thanksgiving.

Ideas?

 

[JasonLion]

Welcome to TFP!

Those sound like calcium flakes coming off the SWG plates. The chemistry inside the SWG cell is a bit more extreme than the chemistry in the pool and that can often cause calcium scaling on the plates of the cell. Most SWGs reverse the current at regular intervals, which causes a thin layer of calcium to come off of one plate and new calcium to start accumulating on the other plate of each pair of plates.

This would be a good time to check your calcium saturation index. A few models of SWG will have calcium flakes even when the pool is balanced but they are far more common when the water is somewhat over-saturated with calcium. Measuring calcium saturation requires knowing all of your water test numbers and plugging them into a saturation index calculator. My Pool Calculator, see the link in my signature, has a CSI (calcium saturation index) calculation.

 

[LeeD]

Check your PH as well. Salt chlorinators tend to increase the PH, and high PH can add to the calcium flaking effect. If your chlorinator has been in use for over a couple months, it might be a good idea to clean the cell.

 

[josta]

I have a similar problem; but the flakes are yellowish and also thin and flaky. It happens only when the heater is on, (when using the spa) and the last time I had the water tested the calcium levels were on the high side. I plan to drain the pool/spa this winter and refill, but what about the flakes that are probably coming from inside of the heater? Should I have the tubes cleaned/replaced or will it just play itself out eventually?

John

 

[polyvue]

I have a similar problem; but the flakes are yellowish and also thin and flaky. It happens only when the heater is on, (when using the spa) and the last time I had the water tested the calcium levels were on the high side. I plan to drain the pool/spa this winter and refill, but what about the flakes that are probably coming from inside of the heater? Should I have the tubes cleaned/replaced or will it just play itself out eventually?

Welcome to TFP, John... :-D

The most important thing in analyzing potential problems with heater and/or SWG is documenting the chemical composition of your pool water. I suggest reading through Pool School, acquiring a good test kit if you don't already have one and posting back the test results. Recommendations based on those test results will be more on target.

 

[josta]

Thanks for your response; I went to the "Pool School" and added info to my sig. I also did a search on this topic before posting my question originally.

I just got back from Leslie's after having the water tested:

FAC=2
pH 7.4
Calcium Hardness=500

(he stopped the rest of the testing and dumped the water out after he asked me if I was going to drain and refill the pool, and I said "yes")

Pool water is about 4 years old and 55 degrees, if that makes any difference....

I'd also like to note that a well-meaning friend who says he used to work in a pool service company acid-washed our spa early last summer. The plaster is about 6 years old, and he used pure acid to do the wash, then rinsed it off as I watched. For the next several months, the white plaster in the spa kept flaking off and finally stopped flaking off a couple of weeks ago.

I don't know if that would have anything to do with the flakes now coming out of the pipes. I never had these flakes coming out of the pipes om the spa until a couple of months ago. I wonder if what is coming out now (only when the heater is on) is residual? The size of the yellowish flakes vary from a little larger than a grain of sand to about 1/4"-3/8" in diameter.

 

[polyvue]

FAC=2
pH 7.4
Calcium Hardness=500

([Leslie's] stopped the rest of the testing and dumped the water out after he asked me if I was going to drain and refill the pool, and I said "yes")

Well, I don't think they did you any favors here! :lol: Wonder why they thought that the rest of the numbers wouldn't make a difference in how you treat your water (despite the fact that you're planning to drain?) The pH, as you probably know already, is OK. The Calcium Hardness is high, so that suggests that your pool water is already saturated with calcium. It would be nice (for you) to know the other numbers: Combined Chlorine (CC), Total Alkalinity (TA) and Cyanuric Acid (CYA). Leslie's may or may not be a reliable source for these. Perhaps you should consider getting your own test kit prior to opening in the spring so you can test the water in your newly drained/filled pool.

Pool water is about 4 years old and 55 degrees, if that makes any difference....

I'd also like to note that a well-meaning friend who says he used to work in a pool service company acid-washed our spa early last summer. The plaster is about 6 years old, and he used pure acid to do the wash, then rinsed it off as I watched. For the next several months, the white plaster in the spa kept flaking off and finally stopped flaking off a couple of weeks ago.

I don't know if that would have anything to do with the flakes now coming out of the pipes. I never had these flakes coming out of the pipes om the spa until a couple of months ago. I wonder if what is coming out now (only when the heater is on) is residual?

I've never acid-washed my own pool and can't assess whether this was the proper method (other members may have something to say to this) but since you report a recent history of flaking, perhaps what you see now is indeed residual from the acid wash.

The size of the yellowish flakes vary from a little larger than a grain of sand to about 1/4"-3/8" in diameter.

 

[josta]

Hope you guys had a good Christmas!

Ok, here are the test results with more information:

FAC 4.75
pH 7.8
TA 60
CH 390
CYA 46
Salt 2700

So, should I drain and refill the pool, and what should I do about the flakes coming out only when the heater is running?

 

[PoolGuyNJ]

Test you fill water too. Trying to drop the calcium level with more hard water is of little use.

Drop the pH to 7.3 and the calcium will better stay in solution. Add the acid slowly, 1 hour time periods work well to prevent the Alk from taking a hit.

Salt is low. Bring it up to 3K.

Alk is a little low. Add some after dropping the pH. This will likely raise the pH a point of so to 7.4 which is where you want to be.

Scott

 

[josta]

Thanks, Scott!

I should also mention that the flakes; especially the larger ones, are yellowish/brown on one side only. I wonder if it's from the calcium flakes from the acid-washed spa that somehow made it past the cartridge filters (yes I maintain the cartridges well) and accumulated on the heat exchanger, "cooked" there (hence the yellowish/brown on one side only) then flaked off and into the jacuzzi?

 

[PoolGuyNJ]

Sometimes stuff falls onto the return plumbing when removing cartridges but it sounds like the one sided flakes are coming off the header of the heater. The heater has a cast header, right? Check the bond wire on the heater too. You'll be looking for a low DC voltage from the bond to ground. It should be 0 volts for a good bond. A bad bond wire can contribute to scale formation. It won't cause it, just make it an attractive surface.

Scott

 

[Jaimel]

Had my salt pool for 2 months and had the white flake problem. Lowered my ph/ alkalinity with muratiac acid and dropped the water down so the skimmer could work properly. If your water level is too high it won't filter well. I added the acid on a daily basis( low and slow). No more flakes. It took me approx. 9 days of testing and adding the acid. Days were in the low 70's...nights 40 ish. Hope this helps