FAS-DPD Delayed Pink Results

[LandCruiser]

I have a 12*22 oval Bestway vinyl pool (approx 6k gallons) that I've been running with a SWG since April (I have the smaller SWG, I know, mistake I should have gotten the bigger one but nothing was in stock earlier this year so it is what it is now). Pool gets a lot of direct sunlight basically all day and ambient temps have been over 100F for several weeks with pool water frequently at 89F. Being new to pool maintenance I'm struggling with several things.

Lately I've been struggling to get detectable FC levels using a FAS-DPD test and my pool water is getting cloudy and I can see some algae growing on the walls. I tried to get my CYA up to about 75ppm to follow TFP advice but things seemed to go south when I did. That's when I can't get any pink when I add the 2 dippers of R-870 powder. If I then try to test for CC, typically I won't get much if any pink when I add the 5 drops of R-003 but if I leave my Taylor SpeedStir running while I log my test results, I finally turns pink. If I add the 871 test reagent, the water turns clear again. If I leave the SpeedStir running, it will again turn pink, I can add another drop of 871 and it will clear. I give up after about 3 repetitions of this meaning I'm either at .6 CC or 1.5 CC depending if I'm testing at .2 or .5 FC.

What does this mean? Do I have more CYA than I think I do and the CYA slows down the test results? Should I just do the test once until it clears and stop letting it continue to stir after I'm done?

When I test CYA using my Taylor 2006 kit I'm trying to make the dot totally disappear. I have good vision so it takes a lot of test liquid for the dot to become obscured. There is a point where the dot gets harder to see and stays about the same until I really fill to get it to disappear. Is this first "harder to see" the limit I should stop at? I confirmed my results by doing a 50/50 mix of pool water and filtered tap water and got within 10ppm (80 with just pool water and 70 with 50/50 mix). Filled the pool and tested again and now I'm testing at 50 CYA.

Anyway, I am trying to SLAM now to clear the water, I added 1 gallon of HDX Liquid Chlorinator (10% chlorine) and I waited about an hour or two to let the water circulate and tested with FAS-DPD and that's when I registered 4.5 FC. The "effects of adding" in the app makes me believe that my FC should be above 17PPM with the addition of bleach.

Help, what am I doing wrong? If it was algae bloom wouldn't I see a lot of CC? Or is the fact that my liquid keeps turning pink indicative of high CC? Why the delay on turning pink after adding the R-003 drops?

Perhaps I don't have as much CYA as I think I do? When I first added CYA and got it to 30ppm, the SWG was more effective and I was frequently testing 3ppm FC (before the extreme temps though).

 

[Texas Splash]

Welcome to TFP! So let's go over a few things:
- Don't add anymore stabilizer. Go to the FC/CYA Levels (SLAM tab), find your CYA and that's the FC you should be at.
- Be sure you lowered the pH to about 7.2 before increasing the FC to SLAM level.
- Then follow the SLAM Process page until you pass all 3 SLAM criteria. That's key to removing algae.
- Yes, the dot should disappear. Don't squint or force yourself to see the dot. There's a little flexibility in the testing results, so just be sure at a glance you don't see it.
- Liquid chlorine is good, the best for maintaining the SLAM level.
- Disregard the water sample going back to pink. Once you do your FC test, record it and move on. If you wait, it will do that,

Let us know if you have more questions. Good luck!

 

[LandCruiser]

Hey awesome. I didn't know if my post event went through, I couldn't find it (must be post approval for new members!).

Well, I didn't lower PH first, oops on my part. Is that an issue?

I added 1 gallon of 10% Liquor Chlorinator the first day Saturday, 1 gallon the second day Sunday when I had very little FC in the morning and this time I validated 30 mins later that my FAS-DPD showed 19.5 FC.

Tested last night and had FC at 5 and this morning and I had FC at 2, CC at .5. water is looking pretty good but decided to continue with the SLAM so I added 3qt, 1 cup of Liquid Chlorine targeting 17 FC per Pool Math.

Decided today I might turn the SWG on to try to keep the FC in SLAM territory but after a few seconds, the Intex SWG gives me a low salt error.

Head is spinning a bit now, is it because of the high FC throwing off the SWG? Water tests at 3200PPM from Taylor K- 2006-SALT (and double checked with Chlorox salt test strip).

Is my SWG cell dead after 2 months? Did I finish it off for dead by cleaning with vinegar (the plates looked fine but the low FC had me wondering if they were working optimally so followed the Intex manual to clean).

I know I should probably wait to see when I'm done slamming but the 150000 gallon SWG is finally in stock and maybe this means I should just get it and move on from my 7000 gallon model even though I just got it!

 

[LandCruiser]

Update, I just tested FC now after adding chlorine early this morning at 7am and my FC is 9.5 so it's not THAT high given it should have started at 17. Drop almost half within 6.5 hours?

Still worried about the SWG, I overpaid for it because nothing was in stock originally.

 

[Texas Splash]

Drop almost half within 6.5 hours?

That's quite a drop. You definitely have something going on in that water. Do your best to keep it elevated and maintained properly with liquid chlorine. We'll come back to the SWG soon, but you might consider contacting who you purchased it from. It might still be under warranty.

 

[LandCruiser]

Direct sun basically all day with ambient temps over 90-100F for weeks on end? That's why I'm wondering if I need more CYA (after SLAM obviously).

SWG worked without low salt error before attempting to clean as directed in manual with vinegar yesterday. I only cleaned wondering if the output of chlorine was reduced which led to algae problem. I can't imagine I'm going to have great luck contacting Intex for warranty support but I can try.

 

[Texas Splash]

That's why I'm wondering if I need more CYA (after SLAM obviously).

Right, so let's be sure to get that cloudiness to go away as well as any residual algae you saw earlier on the walls. Then we'll see what results you get from the OCLT as the final step. I agree, once you get past all of those issues a proper CYA is in order. Totally understand the heat and sun. My pool is full sun without a lick of shade. HOT.

 

[LandCruiser]

FC ended at 5ppm when I tested at sunset. Added 82oz liquid chlorine to SLAM to 16, tested at 22. Bit higher than I was expecting but ok? Water looks crystal clear.

Still sweating the SWG...I flipped the polarity on the titanium (triple plate) plug and it runs without the 91 Low Salt alarm. I thought the Intex flips polarity every 6 / 10 / 14 hours to self clean. My calcium is super low so I had it set to 14.

Why would flipping the electrode plug resolve my low salt issue? Assume it's ok to leave it this way?

 

[LandCruiser]

Checked the water at 6am today, 10.5 FC and still brown/gray algae on the walls (barely noticeable btw, never has been noticeable until you brush the walls and a brown cloud appears in the water. Water has never been green or anything, just cloudy was the worst it got. It's crystal clear still now, smells like a public pool.

I've added nearly 4 gallons of 10% bleach since Saturday. That's $20 in bleach. How much longer can I possibly keep this up?

Am I supposed to be checking FC every couple hours and adding chlorine? To keep it at 16? I've been checking morning, afternoon and evening but have only been adding in the morning so far until last night when I added after sun down.

 

[Texas Splash]

Yes, so your last CYA if I'm reading everything correctly was 50, so your FC SLAM level needs to be maintained at 20. That chlorine smell is most likely the chloramines being oxidized from the pool by the chlorine. Basically it's doing its job. You should find a good time pattern of how often to test to maintain the FC of 20 relatively well. It may be more frequent at first but should eventually spread out.

Why would flipping the electrode plug resolve my low salt issue?

I'll have to ask someone like @JamesW for that one.

 

[Texas Splash]

I'm a bit concerned about the brown you are seeing though. Are you on a well? Is there any staining around the pool? Can you post a pic?

 

[JamesW]

I'll have to ask someone like @JamesW for that one.

Not sure what is going on there.

 

[LandCruiser]

I'm a bit concerned about the brown you are seeing though. Are you on a well? Is there any staining around the pool? Can you post a pic?

Not on well water and my city water here is actually very good with TDS around 40ppm (I was a bit of a water geek before new pool ownership, I have a reverse osmosis water filtration system for drinking water and brewing).

As for the brown, it's hard to describe. As I said, you can barely even detect it on the walls until you brush and see tan clouds (maybe tan is more accurate).

BUT, perhaps the one thing I have not mentioned, my liner has a bit of material overlap at the bottom seam and this collects junk and is very hard to get a brush into the flap. There was definitely reddish/brown "growth" beneath the flap around the bottom outer edge of the pool that I've also been trying hard to brush.

Oh, and my CYA is closer to 40ppm so I'm targeting 16 FC for my SLAM. My earlier statement being 50 was before I added some fill water and I've also read on here about more consistent test methods that I've put into practice.

 

[LandCruiser]

Here are some pics, I just noticed the corrugated hose has visible "something". It's honestly tough to know if this isn't just dirt blowing in? I'm going to run out of FAS-DPD test reagents soon trying to keep this up.

Forgot to mention too, the reversed plug on the SWG was short lived, today it showed low salt again. Really appreciate the help and advice so far!

 

[Texas Splash]

Humm, it does look like there's something on or in that hose.

 

[LandCruiser]

Thanks for the help @Texas Splash , I came out the other side after 4 gallons of 10% bleach and panic haha. My water is crystal clear again. My FC is usually 1-1.5ppm in the morning now and I am adding bleach to reach 3ppm until I figure out why my SWG isn't working. Based on the sequence of events, seems like the cell is defective and I got algae in the first place due to this. Cleaning it probably finished it off and now it reports low salt.

I may make a new post for this. Thanks again for the hand holding during my SLAM!