Not using as much chlorine as I expect?

[superuser]

For some reason my pool doesn't seem to be using the amount of chlorine I'd expect for being in SE Texas, with the visible issues I am fighting. We bought the house last fall, and I've been steadily working to clean the pool up to TFP norms. It wasn't green when we bought it, but you could see it needed help. Much of the pool is clean and clear, but parts are most definitely not. Case in point, I have visible dark algae stains on the bottom (verified with a trichlor tablet), light brown stains on the walls (already did an AA and got a lot of it though), have already scrubbed off a bunch of black algae spots along the tile line, and today's project was cleaning the light. That one had a ton of algae on the chrome bezel, which I scrubbed away today, and I still need to pull it out of the niche and see what slimy monster awaits. I finally worked on the green in the skimmer throats a bit too. Every time I brush, and I brush usually daily (I WILL get this pool completely clean!), I get little poofs.

Despite all this, I can keep my FC at ~5ppm with ease and I can never detect a color change when I add R-0003. Yes, I need to order the reagents so I can switch to FAS-DPD testing, but I honestly expected to see the drop tests to show. I let my CYA drop all the way down to 20 from the heavy rains just to see what happened, and while I consumed a little more chlorine it wasn't a dramatic increase. So I did bring my CYA up a bit (between 50 and 60, lets call it 60) and today since I was loosening up more gunk I threw in a couple pounds of trichlor the previous owner left me. The drop test is ... purple ... and I'm sitting here curious how long it'll take to come back into the comparator block's range. It should be at SLAM level or close by Pool Math, but I'm not looking to seriously track a slam just yet until I get the cleaning jobs fully tackled. Just trying to keep moving forward.

So my question, is there a reason given all this that I'm not using a ton of chlorine daily?

 

[Texas Splash]

So my question, is there a reason given all this that I'm not using a ton of chlorine daily?

I'm not sure I'm following, so I better ask in case I'm not the only one confused. The overall theme of your question is that based on the current condition of your pool, you would expect to see more of an FC loss over a 24 hr period correct? That makes sense. But in your 2nd para you mention needing to switch to the FAS-DPD for accurate testing, so I assume you are using the OTO viewer right? But then you state adding the R-0003 drops which are to be used to detect CCs. For the OTO viewer block, we use the R-0600. Are you using the correct drops for the tes you are performing, or am I confused?

 

[superuser]

You're tracking, but I don't use R-0600. I'm using the K-2005, so 5 drops of R-0001, 5 drops of R-0002, read the block to get free chlorine, then 5 drops of R-0003 to get total. I never see the color change when adding R-0003, which is also surprising. FWIW, I've been (previous to switching to the SWG) adding roughly 20-30 oz. of 12.5% liquid chlorine per day to maintain between 2-5 ppm with CYA at 40.

I'm going to order R-0870 and R-0871 in a minute, because I'm going to need it to do a slam eventually and I'd like a bit more accuracy while I prepare.

 

[Texas Splash]

I see. So the fact that there is no change after adding the R-0003 means you have very little to no combined chlorine which is a good thing. (TC = FC + CC). But once you get your FAS-DPD you'll find the drop testing much more accurate that the visual comparator. Our area has been getting a lot of rain and cloud cover which may also be helping to save you some chlorine each day.

 

[superuser]

Yep, more rain this week too. Fun fun