Test! Test! Test!

[rmozer]

I have been dealing with what I believe to be an algae problem for the 2 months. It all started when I covered my pool with a solar cover in Sept. I have been battling green, cloudy water ever since. After a variety of pool store chem analysis and adding lots of chemicals to fix the problem, I just received my new chemistry kit from you guys and I now have the data to address the problem.
I have been running the pump almost 24/7.

My water chemistry as of today is as follows:

FC = 23
CC = 0
TC = 22
pH = 7.2
TA = 120
CYA = 40

The water is still very cloudy, but the green has turned to a milky color.

I think I'm headed in the right direction with the chemistry, but it may take more time for the sand filter to remove the particulates. Is there anything I can add that will help speed up the process? DE to the skimmers? I also have a powder product that is supposed to enhance the filtration effectiveness by adding it to the skimmer.
Can you advise? I really need to get this pool closed. I've been lucky so far that the leaves are just starting to fall.
Thanks.

 

[ping]

Re: cloudy water

Welcome to TFP!

With your proper test kit you are well on your way to clearing up the pool. Keep the FC above 16 until you pass the OCLT. Don't bother testing the OCLT until the pool is clearing up. I would leave the cover on for a day while at shock level then remove it for the rest of the process if you did not have it in the pool when you started shocking. Brush the pool everyday and keep the pump running 24/7.

Some basic questions:
What are you using for shocking?
What is the CH level? Need to know if you are using calhypo for shocking.
Type of pool? liner, plaster, fiberglass
When did you start shocking?
Have you read the TFP shock process?

To let you know, the pH measurement isn't accurate when the FC>10. For now you are in good shape with all your numbers and it will just take time for the pool to clear. Keep reading Pool School and other threads that people are trying to clear up their pools. For now you seem to be doing just fine.

 

[rmozer]

Thanks for the quick response. I really appreciate and I'm so pleased that I found you guys. I have a background in groundwater chemistry having worked in the environmental consulting business conducting contaminant investigations for 23 years. When I take my samples to the pool store, I'm never confident that some of these people know what they're talking about. Some of the are just kids that are just using some basic water chemistry tests, selling me some expensive chemicals and telling me to try this and see if it works.

Enough about that.

I'm not sure what the acronym OCLT means.
When I last added chlorine, I used liquid chlorine I bought from Leslie's last weekend. I added 4 gal over the course of 2 days. It was only then did I see the pool go from green to milky.
The liner is vinyl. Is there any concern for bleaching out the liner color? At what concentration of FC is this an issue, or is it not at all?
Also, how often should I backwash. I have a fairly brisk flow from the jets, but I'm concerned that there may be channeling going on in the filter bed. I will backwash it now, just to be sure I've got good filter access.
Thanks again.

Bob

 

[ping]

Read this article, pool-school/defeating_algae. The OCLT is the overnight chlorine loss test, pool-school/overnight_fc_test. This is one of the three requirements in the shock process. The other two are CC=<.5 and the pool is clear.

You will want to measure the FC frequently enough to make sure you are not falling below your pool's shock value, which is 16 for a CYA of 40. Liquid chlorine is the best chlorine to use as you do not want to add any more CYA to the water. If you do raise the FC too high it can fade the liner, I think you are fine for now, but target about 20 at most when boosting up the FC. Use the pool calculator, http://www.poolcalculator.com/, to adjust your chemicals. Enter how many gallons your pool holds, then add your measured and desired values. The calculator will then make the calculations for how much of each chemical to add.

We recommend backwashing when the pressure rises about 20% above the clean pressure. If you notice a decrease in the jet pressure, backwash.

 

[rmozer]

perfect...thanks again.
Bob