Salt test results compared to SWG readings?

[NUTNDUN]

We made the switch to a SWG and variable speed pump this year. Finally got all of the plumbing done and everything hooked up. Opened the pool Monday night and surprisingly it didn't look bad other than more silt settled on the bottom than expected. We did do a retaining wall and the yard around the pool is still bare dirt so most likely that is the cause. For some reason I had it stuck in my head at the time the pool was 35,000 gallon. I did an initial salt test and it turned the salmon color on the second drop so I counted it as being 400 ppm already in the water.

I dumped 16 bags of salt in and the pump has been running non stop since then at 1750 rpm. To my surprise when I checked the pool yesterday morning it looked like all of the salt was already dissolved. I tested it last night and I came up with 3800 ppm (19 drops) when it turned salmon color. I was going to pump some water out and put some fresh in to drop the salt level down to 3500 but wanted to turn the SWG on to test it and also see what instant reading it showed. It showed an instant reading of 3.249 which is quite a difference from the test kit.

I don't know how much affect water temp may have but currently it is showing 57*. My other test results are currently sitting at:

FC: 4ppm
CYA: 20 (Started adding stabilizer granules via sock method last night, want to have this at 60)
CH: 150
TA: 80
PH: 7.8

As a side question. Now having the variable speed pump and running at lower rpm's obviously the skimming action won't be as good. We used to normally have both skimmers and the main drain open all the time with the old single speed pump. Is it best to keep the main drain closed all the time to help aide in better skimming from the two skimmers?

 

[Swampwoman]

Greetings, Nutn.

For the salt, don’t add or dilute until you’ve run a bit, then go by your swg but make sure you have it set to the right cell size in your panel readings. I don’t have your brand of swg, but I’m assuming that reading means 3249. It may read lower in cooler water temps so as long as it is producing, wait til the water warms up and see how it reads before diluting.

A general rule of thumb is that how the swg reads it is what’s important...and that there’s generally a variance between tests and swg panel.

Re Vsp, you will need to experiment a bit to see what rpm give you the ideal balance of skimming action and low electric useage. Every pool is a bit different depending on feet of head and hydraulics.

 

[NUTNDUN]

Thank you.

I will wait to do anything with adding or diluting. Checking it was set on the correct cell was one of the first things I did because of hearing about it could cause damage. Looking forward to the learning process and see how it does. The pool is from the late 70's or early 80's and I know all of the plumbing is 1 1/2" so I am sure the flow isn't as good as it could be. At 1750 rpm the filter gauge is showing 3 psi.

 

[Swampwoman]

Yeah, I don’t think you’ll get much skimming action at that setting The good news is that even if you run it at 2400 or so you’ll still save a ton on electric — even @ 3000 you’re saving more than half!

 

[Jimrahbe]

George,

I run my pool at 1200 rpm and get pretty good skimming action.. But, each pool is different, and you will just have to find the best speed for you.. I do have a program that jacks up the speed to 1500 a couple of times a day, but I am not at all sure it makes much difference.. Just too lazy to update the program..

I have found that skimming at a low rpm works, it just takes a little longer. In my case I run my pool 24/7 because I like generating a little chlorine all the time...

I would take a look at what debris are on the pool surface and then wait 12 to 24 hours and see what it looks like.. Don't try to adjust the speed based upon what you see happening in just a few minutes of skimming.

Thanks,

Jim R.

 

[NUTNDUN]

I think the way our pool is laid out makes it difficult to get the water to circulate from one end to the other. It is a lazy L shape with the two skimmers, one in each corner of the deep end and one return nozzle in each corner of the shallow end. I might see about getting smaller nozzles for the returns to get a little more pressure at the lower rpms and get them pointed a little further upward to try and move the water a little better.