Guidance on SLAMMING

[chris-md]

Hi everyone!

I’m currently SLAMing a relatives SWG 15k gallon in ground pool (I’ve turned off the swg to better control pH for this) and have a few questions:

ph:7.3
CYA: 80ppm
Calcium: 360ppm


I’m not familiar with this plaster they have. It feels like very fine grained pebble finish. Not sure if it’s polished stone or regular plaster. I’m leaning toward some pebble finish (~12 years old)

1) do saltwater pools naturally have thicker water/higher surface tension? I see what looks like skin or film when the water is gentle agitated, and in my freshwater pool of yore that always meant high pH and corrected with acid. Not so here. Trying to figure out if this is inherent to swg pools or a sign of biologics.

2) can cahypo damage the plaster? I’m adding it prediluted, but I’m seeing white powder settle to the floor (calcium precipitate I’m assuming and not Undissolved calhypo), and in some places there appear to be bleached spots. But I’ve never known SLAMing to damage pool finish like this, least of all when you predilute. And I did this on my pool that had new pebbletec with beautiful blue dye. So I’m confused what could be happening with these white spots.

3) why would I be having a hard time achieving the 32ppm level? Inf the evening It’ll be 28ppm, and I’ll add what should be 6pom more. Come back in an hour after giving it a chance to dissolve, and the reading DROPPED to 24ppm. In the last few days I’ve successfully recorded over 30ppm only once.

4) at 80 CYA, at what level is my chlorine at risk of uv degradation?

thank you!

 

[YippeeSkippy]

Chris, you can't easily SLAM a pool with a CYA of 80. You need a partial drain and refill to lower your CYA and then in turn that lowers your chlorine requirement. You should be using Liquid Chlorine only for the SLAM process. Using Cal-hypo is going to raise the calcium level in the pool excessively.
Do you have a full set of test results from a reliable test kit??

Please review the SLAM process procedure as I think you're confused about it-
SLAM Process

Maddie

 

[chris-md]

Hi maddie

thank you for your reply. I’ve done this before on my own freshwater pool with success, but this is the first time I’m doing it for a saltwater pool. I use the Taylor titration kit everyone here loves, and balanced all chemicals before I started slamming.

hence the CYA being at the swg recommended 80 ppm.

these were the readings before I started this process:

CYA: 80ppm (was closer to 20ppm 2 weeks ago, which probably encuraged my issue)
CH: 360ppm
TA: 110
pH: 7.2
Situation I was facing: yellowish algae on the pool wall that wouldn’t come off with a brush (some, not all), and the salt cell at maximum wasn’t putting out more than 1.5ppm AFTER cleaning. Suspecting biologics, Experimentally I turned the Salt cell turned off overnight to measure the loss, and had ZERO chlorine the next morning. That’s when I knew I had nasties in the water and needed to SLAM (first OCLT I lost 12ppm).

Do you have any thoughts on the damage to plaster? Ive not known this process to damage plaster before so not sure what to make of the white spots.

 

[YippeeSkippy]

Are you sure its not staining? Perhaps metal staining?

How big is the salt cell? Only clean it when its dirty as cleaning takes off some of its lifespan.

 

[chris-md]

I can’t speak to the salt cell size unfortunately. As this is my relatives pool, and my first with saltwater (my own was fresh water before moving in with family after relocating), my knowledge is based on freshwater pool and am still on the learning curve differentiating the care. Wasn’t aware that there’s a sizing.

my relative actually maintains the salt cell, as I have no experience with it. He cleans it like clockwork on every 90 days in accordance with…whomever it was that told him (either pool store or installer, I’m not clear which).

are metal stains white? Would they result from superchlorination? I have no experience with them so wouldn’t know them if they smacked me in the face unfortunately.

 

[cowboycasey]

SLAMing at CYA 80, SWG levels is fun.. the best way I have found is keeping the FC level at 31 at all times.. I check every 2 hours and bring it back up.. You want to kill it FAST... once the FC level is at 31 it does not take much to keep it there...

Use liquid chlorine, it is easier... Cal hypo is a way but to much of a pain and will raise your calcium level..

Let them know not to clean the cell every 90 days.. teach them how to use the TF100 or Taylor K-2006c kit and how to use the poolmath app.. if they keep the CSI under 0 to -0.30 the cell will never need cleaned.. mine lasted 8 years and I never cleaned it once...