Would high PH cause sudden algae/combined chlorine?

[uraceulose]

Added a SWCG 3-4 weeks ago and it was maintaining chlorine levels great. After reading that the cell would shut off at a water temp of 52* and that cold water reduced the life of the cell..I shut it off and put it on the shelf at about 56* pool water temp.

CYA was at 80 the last time I had checked the week of installing the SWCG.

My PH was steady and CSI looked good with the warmer water temps while I was running the PH from about 7.2 to 7.8 and water was 75-85 degrees.

As the water temp dropped below 60*, I started to reduce my testing regimen as the SWCG was maintaining and actually raising the FC levels as the water temp came down even as I backed the SWCG from 60 to 40 to 20 to 10/8/6/4...never got below 5.5 and as the water really dropped below 60*...it would pop back up to 8-10.5ish FC in a day if I left it without backing down the SWCG %. First few weeks owning it so I figured dialing it in was part of the learning process.

Meanwhile...CSI was wanting me to run the PH closer to 7.8 or 7.9 in order to stay below - .30 so I let it and it seemed to really be stable at 7.8-7.9 with no acid required for about a week and a half just staying in that range (checking PH every other day at this point).

Last week on Thursday...I got to 6 PPM FC...I added 3 gallons if memory serves of 10% liquid chlorine...came out the next evening and it was at 6 or 7 FC...overcast day and 55* water temps...I knew something was off so I tested CC right then and for the first time in months I had pink water and tested at 1.5 CC.

At that point I assumed I was at 80 CYA and had about 15 gallons of chlorine on hand but I DID NOT check PH and assumed it was at 7.8ish as it had been for the prior few weeks. I dumped in 10 gallons and expected it to help.

Since then I've added 30 more gallons and even had it at 50 PPM FC late last night finally showed 0.0 CC

This morning I had to get out of here super early for work and could not test. Got home today at 3 pm and am already back down to 32 PPM FC and up to 2.5 PPM CC. There are no signs of visible algae, scrubbed pretty good with a mr clean magic eraser in skimmers (keeping very clean), running robot vacuum every day and keeping leaves skimmed.

I re tested my CYA this afternoon after all of this and it is actually at 70 CYA. My thinking is that this should have made it "easier" to SLAM?

Did I just really mess up by not KNOWING the PH before initiating the SLAM? It's my first SLAM sorry guys.

Filter pressure is very low and has not moved in psi, pump rpm, watt draw.

Any ideas or should I just continue to maintain minimum SLAM levels for the 70 CYA and be patient?

 

[mknauss]

You are not following the SLAM Process. The higher than necessary FC levels are messing with you.
Follow the process.

 

[uraceulose]

I ran it at 25-30 ppm FC for the first 3-4 days per the SLAM guidelines.

It’s was up to the 50 for about 12 hours I guess due to a miscalculation on my end.

 

[uraceulose]

It had a tough time getting to 31 ppm FC assuming I was at the 80 CYA.

I added based on pool math (which is always been very accurate) and my pool size and it would seem to stay at 26, 28, 29, 27, 26.5 etc after checking after pump running pretty good for an hour then checking another hour or two after that.

Then I tested today at 70 CYA (had 5-6 inches of rain the last 30 days) so the FC levels I was at should have been SLAM levels.

 

[uraceulose]

I was at 22 ppm FC added 4 gallons and ended up at 50 ppm so one of the tests I must have way off counted the drops or something I don’t know

 

[Mdragger88]

Clean your test cylinder with alcohol.
A dirty cylinder can make it show cc’s on the test.

 

[mknauss]

It also is very difficult to SLAM at elevated CYA levels. Best to drain off some water and refill to get CYA to 50 or less.

 

[uraceulose]

Thx, it could be that test cylinder. Really hoping to not drain but will if I need to. We've got 6 inches of rain coming the next few days.

 

[mknauss]

Then drain down 6 or 7 inches and fill with the rain.
Even better is if you can harvest some rain water from a nearby downspout.

 

[uraceulose]

I'll send a picture here in a bit but the pool looks crystal clear...FC was down to 19 ppm last night. CC was still measuring at 3.5 ppm. CYA still @ 70. We had a pretty big storm come through and ended up with 10-11" of rain so it was tough to get out there and test but there's zero leaves...scrubbed backs of weirs, skimmers, cleaned baskets..filter pressure is almost zero and water temp is down to 49* now.
Is this the type of thing where I am potentially chasing a piece of algae the size of half a dime or something? It's hard to get every single nook and cranny in the skimmers for example up behind the weir doors but I can see pretty good there is no visible algae and I've definitely scrubbed what I could with a magic eraser

 

[Mdragger88]

Just trying to cover all bases here,
Have you added anything else to the pool lately? Like non chlorine shock or some kind of stain/scale product?
Also, are you doing the cc test immediately after the fc test and doing the drops consecutively? If you let it sit it will become pink and cause you to add more drops resulting in a falsely high cc calculation.

 

[uraceulose]

Thank you.

Nothing other than the salt (which ran fine for 2-3 weeks), maybe a half gallon of muriatic acid, liquid chlorine.

All CC tests done immediately (within 30 seconds) of the completion of the FC test.

 

[Mdragger88]

Have you tried the cc test on your tap water? (This may or may not be helpful unless you have a previous comparison test because some tap water has cc’s in it)
How old are your reagents?
Aside from those things you may just need to hold what you have (keeping w/slam process) for a few more days since cc’s are an indicator that the chlorine is “working on something” which may simply be contaminants from the deluge you’ve experienced. It can be hard to be patient when Murphy comes at you but at least the cooler weather makes it a bit easier to maintain slam level.
To be thorough, you’re running slam level fc water through any water features daily, blasted any floor drains with the hose, & turned over all other stones aka scrubbed all hidden areas?
* check the weir door foam- most comes out.

 

[uraceulose]

Here's a couple photos from today...I threw the Legend in yesterday after restoring this last week with new bearings, hubcaps/tires, backup valve, couple other misc parts and we got a decent amount of leaves the last few days so I let it run with the robot...photos are to give perspective...cleaner is in 8.5' of water and you can read the words on the model on the cleaner pretty easy.

I found a little SMA antenna on amazon that added some decent range to the ChemCheck...cleaned up the wiring a bit and mounted the relay to the bottom of the IntelliConnect box securing it with double sided 3M tape. Another thing I discovered..I purchased a braided 15' long usb a to micro usb cable and ran it over to a surge protector on my battery operated ChemCheck and it can be ran continuously with the battery plugged in effectively becoming 110 powered preventing from having to remember or go plug in every so often.

It's nice to have the water softener, sump system for the pool house, ChemCheck, Heater, booster/cleaner, pump and SWCG all on that one app.

The light being on Alexa really works nice for my setup because I moved the switch right over inside the pool house, ran wire through the attic and turned the existing 2 gang switch box into a 3 gang. It allows me to have the physical switch right on the wall inside the insulated pool house but still right next to the pool where you can easily visibly see the entire pool while flipping the switch and walk a very short distance if I'm not there/no phone etc but at the same time allows me or anyone else to say "alexa turn the pool lights on/off for 2 hours" or something to control that way from anywhere on the back half of the property or inside the house.

Those Alexa dot/pops went on crazy sales for Prime Day/Black Friday so we got about 8 and just stuck them everywhere

 

[uraceulose]

We'll see how it goes but I drifted down to 23.5 FC by this morning BUT CC was finally down to .5

CYA @ 70 so I added just about 2 gallons of 10% this morning @ 10 AM PST

Hopefully I can pass an OCLT tomorrow morning and let it drift down to normal levels so I can acclimate, calibrate and use the PH sensor.

 

[dereksanders]

I would check the OCLT again after passing, just to make sure. Nothing worse than having to SLAM again. The SLAM is most definitely a process that has to be respected and followed.

I checked my OCLT thrice.

 

[uraceulose]

Yes sir will do. I'll just keep it up here for 3-4 days then to be sure

 

[Chris_Porter]

You’re on the right track with your SLAM. Not knowing your pH initially isn’t a big issue, but aim for 7.2-7.4 for optimal chlorine effectiveness. Your high FC and rising CC show the chlorine is working. With CYA at 70, keep FC between 28-35 ppm and continue scrubbing, vacuuming, and filtering. The cold water may slow things down, but with patience, your pool should stabilize soon. Keep it up.

 

[PoolStored]

With CYA at 70, keep FC between 28-35 ppm

There is no need to raise FC above 28 for CYA of 70. 28 and below are safe for CYA of 70. It is about maintaining FC, not raising it above SLAM level.

Add enough LC to get to 28. Don't add more to raise above 28.

 

[uraceulose]

Thank you guys.