Central Valley SWCG w/ Low CL & High PH...

[aylad]

Make sure that you are maintaining chlorine in the pool while you're adjusting the TA and pH, though--if you allow an algae bloom, it will just throw off everything you're trying to do.

Janet

[nomar116]

Ok, not alot of success on my pools condition. Frankly I seem to have regressed...

The temps here have been dropping over the past couple of weeks and we've seen our first hour or two of rain this year here in California. Not sure if either of those have to do with my problems but here goes.

On Saturday I noticed a significant amount of algae collecting on the walls of the pool. I used the brush to stir up the pool and ran the pump for the next 24 hours. Turned the sanitizer's output on 24 hr max mode and also added one pack of chlorine shock (only rated for a 10,000lbs pool but it was all I had on hand).

On Sunday I bought some more chemicals and retested the water. Now Chlorine measured over 5 ppm and some of the green seemed to be reduced. However, total alkalinity hasn't really come down. I added two gallons of muriatic acid, one on Thursday and the second on Friday. I've made all my readings using the 10mL Taylor test. On Thursday total alkalinity was 11 drops =~ 275 ppm. On Saturday the pool had come down to 10 drops and after another gallon of acid, today the pool is measuring at 9/10 drops still which is =~ 250 ppm... So that doesn't seem right.

Theres actually some bugs swimming in the pool, too. So that's pretty gross! I bought CYA, some Algaecide/Clarifier and more shock. The clarifier says I need to wait til the Cl drops and today it is still ~ 4-5ppm and hasn't really fallen much. I'm running the pump 6 hours a day at this point and still havn't added any CYA since I'm trying to get the CL level to drop (?).

So what all am I doing wrong? :/

[waterbear]

If you post a full set of test results we can take you step by step to a perfect pool. However, we need to know where we are starting.

[aylad]

Ditto what Waterbear said--and don't add the clarifier--it's going to increase your problems, not help them...

Janet

[nomar116]

Ok, thanks again for the replies. As requested I took a total set of tests and here are the results:

Akalinity 225ppm (I've added a total of about 5 gallons of muriatic acid of the past month!)

Free CL - 1.0 ppm

Combined CL - No color change so zero?

PH - 7.1, doing a Base Demand test took 5 drops R-0006 to bring it to a 7.4.

Calcium Hardness - 50 ppm

CYA - 38 ppm

And from these numbers a SI of about -0.8 - 1.0 (I'm actually measuring water temp right now, my guess is somewhere around 65degF, its awful cold!)

Paul

[nomar116]

And total temp was 67degF. Any suggestions? Thanks a million

[aylad]

Hi nomar,

I'm so sorry this thread got overlooked!! I hope you're still around.

I know this is way, way late, but just looking at your numbers, I would say the following:

Check the instructions for your SWCG, but most of them want your CYA to be around 70-80 to make the cell work more efficiently. That alone may help your chlorine output.

When adding acid to lower total alk, it needs to be added all at one time. If you add a little at a time over several occurances, it will lower the pH but not do much for the alk. What you need to to according to these numbers is to either aerate the water or add Borax to raise your pH to7.6-7.8, then add enough muriatic acid to drop the pH back down to NO LOWER THAN 7.0. With this pH drop, your alk will also drop. Then aerate the water so that your pH rises again, but the alk will stay lowered. When the pH gets back up into the mid to high 7's again, then you can add more acid to drop it back down to 7.0, further lowering your alk. It's a ratcheting process and takes a little patience, but it will work. The good news is that pH rises in pools with SWCGs naturally, so hopefully it won't take too long to get the pH back up after the acid additions.

After you're finished with adjusting the pH/alk, then use bleach to shock the pool to get rid of any remaining algae. What is the total gallonage of your pool? And is it vinyl, gunite, plaster.....?

Generally when fighting an algae bloom, it's best to do that with bleach instead of depending on your SWCG to do it--it will wear out your SWCG too early--it's more made for maintaining chlorine than generating large quantities of it all at once. Once you get the alk where you want it, the CYA up higher, and the pool shocked, then you should be able to go back to chlorine maintenance with just the SWCG and be all ready to go for next year!

Janet