Slam issues

[tcat]

How important is the <1ppm overnight? I've been slamming for 3 days now, and each night I'm getting a 2ppm drop, with CC right near .5. Pool is clear since day 1. Was getting closer to 4ppm overnight drop, reason for slam. Dropped pH to 7 when I started, CYA was 60. Been shooting for FC 25 every 6 hours. I've been running pump 24/7 at 2100.

Only thing I can think is maybe my CYA is higher than my eyes tell me. Sometimes can't tell if that dot is a dot or a shadow. Is it ok to recheck cya during a slam?

 

[splashpad]

Only thing I can think is maybe my CYA is higher than my eyes tell me. Sometimes can't tell if that dot is a dot or a shadow. Is it ok to recheck cya during a slam?

Yes, CYA can be affected by cold temps (under 60-70F), but not usually other chemicals as it is a refractivity "test". So you must have bright, indirect light to read the result correctly.
If you haven't already, you can purchase a CYA 50ppm standard solution, which teaches the user/owner what 50ppm CYA looks like in *their* conditions.

 

[tcat]

Yes, CYA can be affected by cold temps (under 60-70F), but not usually other chemicals as it is a refractivity "test". So you must have bright, indirect light to read the result correctly.
If you haven't already, you can purchase a CYA 50ppm standard solution, which teaches the user/owner what 50ppm CYA looks like in *their* conditions.

I may buy that pentair sliding test gizmo. I think the main issue with the round tube test is there tube and dot are both round, so the "dot" turns into a round dark shadow. Pool has been 84 degrees for 2 months.

 

[splashpad]

I may buy that pentair sliding test gizmo. I think the main issue with the round tube test is there tube and dot are both round, so the "dot" turns into a round dark shadow. Pool has been 84 degrees for 2 months.

Someone will correct me if I am wrong, but I believe each CYA test solution must be used with their brand test tube, as the sample volumes used to measure might differ. I don't have personal experience comaring the different testing solution brands, but I seem to remember that being of concern before. Just a heads up

 

[tcat]

Pretty sure it uses same solution, but comes with it, so no issue (Pentair R151226 on Amazon). I just tested again, might be higher than 60, definitely lower than 70. No harm running Slam at next level, right? I'll shoot for FC 28. Going to start using 5ml testing. I use a 10ml syringe with 1ml marks, so 5ml is very accurate.

 

[splashpad]

Pretty sure it uses same solution, but comes with it, so no issue (Pentair R151226 on Amazon). I just tested again, might be higher than 60, definitely lower than 70. No harm running Slam at next level, right? I'll shoot for FC 28. Going to start using 5ml testing. I use a 10ml syringe with 1ml marks, so 5ml is very accurate.

From the CYA Testing Guide page:

TF-100 vs K-2006 CYA Test Differences​

The view tube for the TF-100 does use a larger sample size and it goes down to 20 ppm instead of only 30 ppm as the K-2006 does.[8]

It is a bad idea to mix testing reagents and hardware between different testing kits.

 

[splashpad]

How important is the <1ppm overnight? I've been slamming for 3 days now, and each night I'm getting a 2ppm drop, with CC right near .5.

If (as suggested) your FC is below the SLAM level for your CYA and you are still getting a loss overnight, you are definitely not done

... I just tested again, might be higher than 60, definitely lower than 70. No harm running Slam at next level, right? I'll shoot for FC 28.

I would only do this during the day, just in case your CYA isn't 70, you don't want to have excess chlorine working on your equipment overnight frequently. We do personally bump our FC during the day around here on "messy" days, with no issues, but each pool, owner & water situation is different!

 

[MITBeta]

Are you sure you found all the places that algae can hide? Often when pools are clear but still losing FC overnight, it's because of hidden algae: ladders, light niches, main drains, skimmer weirs, liner seams, deck jets, fill valves, auto covers, etc.

 

[tcat]

From the CYA Testing Guide page:

I found my answer. Think I'll stick with the tube. Still think the dot turns into a dark shadow in any light, making it difficult.

The Taylor #4088 CYA test tube the same as the Pentair #79 S/N R151226 CYA test tube?

Is the Taylor #4088 CYA Test tube and the Pentair #79 S/N R151226 CYA Test tube the same tube? The pictures I find look the same, I searched here as well as Goggle for the answer, anyone here know? Thanks

www.troublefreepool.com

 

[tcat]

Are you sure you found all the places that algae can hide? Often when pools are clear but still losing FC overnight, it's because of hidden algae: ladders, light niches, main drains, skimmer weirs, liner seams, deck jets, fill valves, auto covers, etc.

No ladders or other accessories. How to clean a main drain? Two drains at 8'. Doesn't slam kill it all? Only other possibility is lights, but hate to mess with something that hasn't failed. Deep cleaned filter grids before slam.

 

[tcat]

Still getting CC of 1.0. Getting +/-2 FC from different spots currently 23-25. Pool at 2100 24/7 should be mixing better than that. Waiting 2 hours after LC addition to check. Does slam usually take 3-4 days from a clear pool? I'm guessing half the pool will need to be drained to check lights, but can't imagine they're leaking.

 

[MITBeta]

I don't know anything about lights or drains. My understanding is that unless they are LEDs, you remove the retaining ring and pull the light up onto the deck. With the main drains, I believe you have to swim down and remove the covers.

 

[PoolStored]

Lights, depends on the type. Any pictures of your lights?

Main Drain. You want to dive down and take the cover off, so you can scrub in the drain. Can you take a pic of the drain to confirm it is new style that allows the cover removal?

Cover on and off. Do not remove that second ring. You can use a dumbell to hold you down. TURN OFF PUMP FIRST!

 

[Newdude]

Getting +/-2 FC from different spots currently 23-25

So its 24, +/-1. 25 is 50 drops. I wasn't there and i know you didnt make 50 perfect drops.

Human error really comes into play at higher FCs.

Stay the course

 

[PoolStored]

Lights, depends on the type. Any pictures of your lights?

Just went through your media. Based on that there should be a screw on the top of each of your lights. Take the screw out and there should be wire wrapped around the inside of the lights that will allow you to remove them and place on the deck. Scrub them and scrub the remaining faceplate in the pool. Betcha' got green behind light.

 

[proavia]

Yup, pull the lights. You can let them float in the pool. Scrub out the niche in the pool wall after pulling the lights.clean the exterior of the pulled lights, front and back.

Stay the course, you're close but not quite there yet.

For the Overnight Chlorine Loss Test, take the water sample from the exact same location and water depth.

 

[tcat]

So you can remove lights with water covering them? Is there a gasket that will need replacing? Getting 2 FC drop each night, fairly consistent, whether I check before dawn or an hour or two after.

 

[IceShadow]

See the holes in the ring around the light? They let water behind the fixture that the ring is holding on, so no gasket to worry about. The fixture itself is waterproof, the wire is going to the back of a niche that is also waterproof. The light is meant to be able to be removed by removing the top screw, and then you can lift it out. You may be surprised with what you find in there. You'll want to scrub it out.

When a pool is clear but failing OCLT it's almost always hidden algae somewhere in the pool.

 

[proavia]

In your light pic, see the phillips screw at the top?
Remove the screw
Tilt the top of the light housing outward
Lift the light housing slightly

Congrats - you have now removed the sealed light housing.
No worries about water getting into the housing by doing this.

 

[tcat]

Yep, found YT video. Shallow end was a cake walk, deep is a balancing act. Screw was VERY tight for ¾ of the thread. That brown on the light was abundant on the bottom of the can (dead algae?). Some black flakes (like paint flakes) came out. Nothing "green". White gasket has a bunch of flakey stuff. No water in the bulb area so left it alone (other that running a tooth brush around it). Added 84 oz 10% to get FC back up to 25. Will try again tonight. Removing drain looks like more of a problem (holding breath). Will hope it's not in there. It's getting sucked directly to filter, so "shouldn't" be an issue. Doesn't it all die at shock level?