Prestone Driveway Heat - safe to use to add CH?

[robrinker]

I need to add CH to my pool. The only source of Calcium Chloride I can seem to find locally is Prestone Driveway Heat.

I have attached a MSDS sheet for it that I found.

Is this acceptable to add to a pool?

Thanks,

Ron

 

[JasonLion]

The MSDS lists calcium chloride as the primary ingredient, which is good. They are a little vague about how pure it is, which is common on a MSDS, still it does say that it is at least 90% pure, which is also good. They go on to list the most common impurities and most of them are completely harmless (water and salt). I do wonder about the greater than 1% of strontium chloride however. I don't know for sure if that will be a problem or not.

 

[robrinker]

Thanks for the input. Hopefully someone else can weigh in on the strontium chloride.

 

[waskydiver]

Sorry to bump up an old thread.

Are there any new (or different) opinions to using Prestone Driveway Heat to add CH?

I have a replaster that is about 6 months old, and the contractor just replaced my inset steps, so the pool is freshly filled (if it matters).

Closet I could find to Dow Flakes in hardware store is Prestone Driveway Heat.

Should I go with the Driveway Heat, or "play it safe", and hit the pool store?

Thanks!

 

[chem geek]

This MSDS shows the following composition:

Calcium chloride ....... > 90 - < 92
Potassium chloride ...... > 2 - < 3
Water ........................... > 4 - < 6
Sodium chloride ........... > 1 - < 2
Calcium bromide ................ < 1

I don't see strontium chloride. The above seems OK to use and is consistent with other calcium chloride ice melt products.

 

[Melt In The Sun]

Based on that MSDS, is that not enough bromide to turn it into a bromine pool?

 

[chem geek]

If you were to add 300 ppm Calcium Hardness (CH) using that product and assuming 90% calcium chloride and 1% calcium bromide, then one gets about 3 ppm bromine equivalent. This is worst case since the calcium bromide content is less than 1%. That level of bromine will dissipate (outgas) over time. Peladow would be better though it too has 0.98% impurities beyond the listed chlorides.

 

[waskydiver]

Hmmmmm.... Thanks for the responses...

I'm a bit concerned now. I've creeped up CH up to about 150 now. I put about 9 pounds in a 15,000 gallon pool. And I've been pretty surprised at my Chlorine demand. Waters crystal clear, and really cold (about 45 degrees)

It's at least twice what it's been over the summer.

I've just been attributing it to rains, and I normally do not pay any attention to the water over the winter.

I really know nothing about bromide. Should I be concerned that my cholorine is getting converted to bromide and I have another refill in my future?

I guess I should test for bromides. At what level should I consider corrective action if I do have bromides?

Or am I just being paranoid?

Thanks!

 

[UnderWaterVanya]

I thought Cl converted to bromine shows up as cl in your tests. If i remember correctly the test can't tell the difference.


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[chem geek]

Chlorine will convert bromide to bromine, but as noted you cannot distinguish between chlorine and bromine in the standard test kits. There is a sneaky way to be able to test of it, however. If you take a pool water sample and add a small amount of ammonia to it (one drop of ordinary household ammonia in your 25 ml sample is way more than enough as this is enough for up to around 400 ppm chlorine or bromine), then chlorine will rapidly combine with it to form monochloramine while bromine will rapidly combine with it to form monobromamine (and be in equilibrium with monobromammonium ion). The monochloramine will show up as Combined Chlorine (CC) with no Free Chlorine (FC), but the monobromamine will show up as Free Chlorine (FC) with no Combined Chlorine (CC). So that is a way to distinguish between chlorine and bromine. If there is both, then the FC amount is the bromine amount while the CC amount is the chlorine amount.

I don't think you should worry about it. The initial higher chlorine demand you saw could just be from some initial impurities. See how the demand is after a few days and let us know (for our future reference). Note that in cold water, the demand will be based on breakdown from the UV in sunlight and is independent of temperature. If you want to get rid of the bromide/bromine faster, you can aerate the water.

 

[waskydiver]

Hi all...

Sorry for the late follow up.

Seems the prestone driveway heat worked fine.

My initial concerns about the high cholroine demand came from me not considered all the variables.

In the summer, following my resurface job, I was running my filter 24/7 with Trichlor pucks in my skimmer. It helped with the acid demand and got my CYA into the pool. Everything was fine.

A few months ago, when the pool company redrained to fix my steps, I was only running my filter 8 hours a day, so I put the pucks in a feeder.

So, I had the following going on:

Less Chlorine going in, because much lower water flow.

Less CYA being introduced because of above.

Much more rain, a lot more organics (debris... Worms)... getting into pool and staying there longer.

I largely ignored these factors, and considered that it was colder (so there would be less demand on chlorine from algea growth), plus shorter days = less UV = less chlorine demand.

Also, in the past, I just let the pool go to swamp in the winter, and never paid any attention to the chemistry.

Now, I have everything dialed in, and am starting to get a feel for the different pulse that the pool has in the winter, and everything is fine.

Prestone driveway heat got my CH from about 20 up to a nice happy 230ish. No ill effects. Only issues were my expectations needed to be adjusted for a few other variables that I didn't consider.