Low Cl levels

[nud1l]

I am in the third summer of using a SWG on a new pool. The first summer I ran the the generator at 100% all summer and had good Cl levels all summer. Last year, my local pool store told me I should only be running at 40%. At the lower power, I have been unable to keep my Cl level above 1.0 ppm. They have since advised to supplement with CL hockey pucks. Does this seem like a good strategy? Will it cause any problems or level imbalances?

It is a big pool, 47,000 gallons. I run the pump 7 to 8 hours a day. I'd rather not do more, because it gets expensive. Calcium, ph, alkalinity, CYA, and salt levels are in spec and I keep them stable. I have checked the cell for scale and cleaned it with acid. Last year, I maintained with boosts and shock, but again that got expensive. My phosphates can get high, currently 500 ppb, but the water is still crystal clear and I have little to no trouble with algae.

 

[JasonLion]

Welcome to TFP!

The pool store people are out of their minds. What is the point in having a SWG if you don't use it? Worse, using trichlor will constantly raise the CYA level, which will lead to trouble eventually.

We could give you much more specific advice if you told us your actual chemical levels instead of just saying "in spec", which really tells us nothing.

 

[RobbieH]

What is the point in having a SWG if you don't use it?

If he does, they can't sell him trichlor tabs.

Ignore phosphates, I figure they are selling you something for that, too?

 

[nud1l]

ph 7.9
CH ~175 ppm
salt ~3100 ppm
alkalinity 100 ppm
CYA 20 ppm

They said running at the reduced power level will maximize the life span of the cell. I am constantly adding CYA anyway, so raising that level doesn't seem like a bad thing. They do want to sell phosphate remover.

Should I just set the SWG to 100% and let it run?

 

[CombatYoga]

Hi nud1l,

The Pool School info is extremely helpful - I recommend you read that info. I also have a SWG and find the following link particularly valuable to reference:
pool-school/water_balance_saltwater_generator

SF

 

[nud1l]

SF,

Thanks for the input. I try to maintain most of those levels listed there. Throughout the summer I continually add pH down and CYA. I usually keep my pH in that band, but the best I seem to be able to do on CYA is 30 ppm to 40 tops.

 

[jblizzle]

You CYA should only reduce through water replacement ... so unless you have a leak in your pool and an auto-fill you should not need to keep adding it.

You need the get the CYA up to the 70ppm range and your SWG will not have to work as hard ... for you size pool raising from 20 to 70ppm is 20 pounds of stabilizer

How do you get your CYA numbers? Your own test or the pool store? Pool stores are notoriously bad at that test.

 

[lungs414]

How are you testing?

 

[nud1l]

I thought you lose CYA through the same process you lose Cl, but the stabilizer slows the process. I have no shade cover over it, so my pool gets sun all day. I use the sock in the strainer basket with solid stabilizer, which limits me to about 1 to 2 pounds at a time. They take a few days to dissolve, but I continuously add. I do use the pool store test.

 

[nud1l]

I'm almost color blind, so I'm not so hot a reading the charts. I go to the pool store because I like to have actual numbers.

 

[nud1l]

I guess I can have the wife help me with that

 

[jblizzle]

Get your own GOOD test kit (see link in my signature). The only color matching test is pH. All the other tests you count the drops until the color changes or goes clear. The CYA test involves no color.

You will not get you pool under control without you own kit ... if you took the same sample of water to 2 different stores, you would get 2 different answers. IF you take water to the same store 2 days in a row, you will likely get answers showing changes that are not possible.

CYA never goes away except through changing water out (and sometimes bacteria in the winter in a closed pool).

You need to add 20 lbs of stabilizer to your pool. Hang a sock or 2 in front of ALL of your return jets. There really is not other option if you want your SWG to be able to keep up.

 

[Qwaxalot]

Part of your problem is that your SWCG is rated for a maximum pool size of 40,000 gallons. That said I have seen them work fine in big pools with a little extra chlorine help.

Your major problem is the low CYA level.

By the way, phosphates at 500 is nothing to be concerned about.