Chemical Reaction?

[bennieboy]

ok, so a fresh pool has just been installed and i needed to get the alkalinity right before adjusting the PH, so i added the desired amount of baking soda, this obviously raises ph too and did so to a very high level - off the scale. a couple of hours later i added dry acid to lower the PH, but within minutes off adding this the water started to change color to a brown/yellow type.

I know not to add huge amounts of acid at a time so its not that, any ideas?

Thanks

 

[duraleigh]

You need to help us a little and tell us just how much (quantity) of baking soda and dry acid you added and to what size pool.

It will also be helpful if you tell us your test results prior to the additions and the test results now.

Baking soda would typically have very little affect on your pH.......more information will help us get to the issue.

 

[bennieboy]

ok the test results before were:

Calcium Hardness 0
Total Alkalinity 0
pH 8.2
Total Chlorine 10
Free Chlorine 10
CYA 0

I added around 3kg of baking soda to raise the Alkalinity, tested a couple of hours later, Alkalinity was 80, so i then added 500g of dry acid to lower the pH, within minutes the pool discolored. Not sure if this helps but the pipes have been full of dirty water for a few years prior to the pool just being fitted.

When the pool was first run though a back wash was performed to pull this dirt out of the drain and pipes.

Thanks for your quick response.

 

[bennieboy]

and its 12,000 gallon pool

 

[bennieboy]

sorry, it was not baking soda i added, it was soda ash!!

 

[Richard320]

sorry, it was not baking soda i added, it was soda ash!!

As you discovered, there is a big difference between them.

Strange colors can be dissolved metals in the water; you've been making the pH go up and down like a yo-yo, which can dissolve metals or precipitate them out. Or it could just be mud.

At this point, I'd let it circulate for an hour or two to mix well. Brushing would also help circulate water in the dead spots. Then recheck pH and see what you need to get that right. Get that dosed, let it mix, then shut it down overnight and see if the stuff settles out where you can vacuum it out.

Then go back and do a full set of tests and post it here. And tell us what the water looks like, too.

 

[PoolGuyNJ]

Also wait till the FC drops some. It can cause a high reading too.

Scott