Chlorine Demand Test

[Oakie311]

Hi everyone! I've been lurking for the last week or two, and decided to jump right in and join the forum. This a great community! I'm a new homeowner AND pool owner in GA. Unfortunately when we took possession of the house, the pool was not in the best of shape. The previous owner had a Crepe Myrtle planted in the yard that had such overgrowth that it was basically dipping. She also had neglected it for a couple of weeks when renting back from us.

We've got it pretty back to normal but I keep running into this low chlorine readings. I've shocked it twice (20,000 gallon pool and I used two 1 lb bags each time) and I've switched from granuals to tabs to maybe offer more consistency. PH was pretty high but I brought that back down to acceptable range. However,what baffles me is that after I shock it I get a healthy chlorine reading but then the day after it's basically at 0. I've been researching relentlessly and came across the topic of Chlorine Demand. I'm starting to feel it's probably the culprit. If I'm understanding correctly, it took too much abuse/neglect and accumulated too much bacteria which is basically running the show. So again if I understand correctly, I have to shock the heck out of it to kind of supercharge it to be able to have available FC...is that correct? (My head hurts!)

If this is accurate - My question is, how do I know how much to shock it to meet this demand. Is there a certain test I can purchase? From everything, I've read it's either an all or nothing process. You can't meet the demand gradually.

Thank you in advance for your guidance! loving the support and wisdom of this group already.

 

[jblizzle]

Welcome to TFP!

You still have algae in the pool consuming the chlorine.

We recommend what we call the SLAM Process process to eradicate whatever is in your pool using accurate testing and dosing to only add what your pool needs without concern for damaging it.

Perhaps review some of Pool School starting with the ABC article.

 

[mknauss]

Welcome to the forum!

This forum advocate’s pool owner water testing using a proper test kit. Order a TF100 test kit
The only other real option for a test kit is a Taylor K-2006-C. Be careful comparing prices because the K-2006 comes in sizes, designated by a letter. The basic K-2006 has .75oz bottles. You need to get the K-2006-C to get the larger bottles that you want. Even then it is a little short on the reagent & powder for the FAS/DPD test.

I also have the SpeedStir. It makes testing much easier.

While you are waiting on your test kit add liquid chlorine/bleach to put 5 ppm FC into your pool each evening.

Let us know when you get your test kit and post up the results.

 

[Oakie311]

Many thanks! I'll read up on it and have to commit some time to it this week.

- - - Updated - - -

will do. Thanks!