Green Monster

[coolauzie88]

So I am at a complete loss...

I have a 20x40, 37000gal salt water pool. I have a single SWG (Probably need 2...) that is an Aquarite with a Compupool generator. It was working great until we've had about 26in of rain over the last couple of months. Now I cant get the chemistry right or really know what it is.

The SWG displays 900ppm
Test strips show 1800ppm
had a pool guy come and use an electronic tester and got 6600ppm
Taylor Silver Nitrate drop test - 8000ppm

What is going on??!

I originally only had the test strips and because it rained so much I added about another 1000lbs of salt to get the levels back right on the test strips and the SWG. Then it started disappearing. I checked the CYA and it was 55ppm. I bumped it up to 80ppm. Ever since ive had to add salt its been very cloudy too, no matter how much clarifier i put in.

Can you guys help at all? Im having to resort to just turning off the SWG and using chlorine for the rest of the year i feel.

Do i need a new SWG? is it the board or the cell? what do i really trust to determine my salt levels?

ANYYY information you can share will help! Thank you so much in advance!

 

[JVTrain]

Welcome to TFP!

I'd have a look at this article Salt Water Chlorine Generators Yours may need a good cleaning. How old is the unit? Have you ever cleaned it? When functioning properly, most SWCG owners here tend to add salt to keep the unit happy for levels but their salt test readings aren't as different as yours are between the unit and testing.

Please add the details of your pool, in a similar way as other members including details about volume, pool surface, equipment, sanitation, etc. to your signature by clicking the Settings link in the upper right of the page, then the Edit Signature link on the left side of the next page.

 

[coolauzie88]

Ill get on the signature.

As far as cleaning, i just did a cleanout of the cell with 4:1 water to muriatic acid. it helped bring up the reading on the SWG by 200ppm or so. That was about it.

 

[timerguy]

You've got a bigger problem than cleaning the cell will fix. I'd trust your Taylor kit over anything else. But what I don't understand was the 1000 lbs of salt in addition to what was already in your pool? Did you do a Taylor test prior to adding that salt? If so, what did it tell you it was to justify putting that much salt in?

 

[coolauzie88]

I did not do a Taylor test prior to adding the salt.

i relied on the test strip and the fact that at the time it was very close to what the cell was telling me. I added the salt, it worked for a few days then salt levels on teh cell dropped from 3500ppm to 1100ppm. At that time I bought the Taylor kit to see what was really going on.

Just to be sure - when using the Taylor kit, you add Silver Nitrate until the entire solution goes red, yes? Not when you first see glimpses of red but still swirling it disappears.

 

[timerguy]

It turns from clear yellow to a milky salmon (sort of a pink) color it says red brick, but it's truly not that dark. If you go beyond that, it doesn't change anymore and you're just wasting reagent. There's a you tube video of performing the test. I'll try to find a link to it for you. http://youtu.be/O8R-u_PeN4k Here's a better one! https://www.dropbox.com/s/1wkm5njn34ftzhu/20140903_161902.mp4?dl=0
And that folks is why you need a Speedstir! And the guy is so much more handsome and there's no Phosfree ad either.

 

[Green Goblin]

My experience is that you can't trust the SWG readings, at all, which is very frustrating, because the SWG will shut off at certain levels, even if it is inaccurate.

If you have a very high salt level in your pool, like 8000ppm for example, it may be well above the testing parameters for many common tests, such as pool store devices, handheld testers, etc... Many of these max out at 5000 or 6000ppm, so readings at or above that may not be accurate. The taylor test, might actually be more accurate in such a situation.

I've only tried two test strip brands and found them both to be useless, but I only tried these when I had a very high salt level-- somewhere over 10,000ppm.

I haven't had good luck with pool professionals either, but I live in a small town-- not a lot of options.

The pool store I use is usually within 500ppm of the Taylor kit, in the functional range 2500-3500ppm (for me, for example). I'm not convinced the Taylor kit is very accurate, but it is very precise.

Since you explain that your pool was working properly, and then it stopped and you added what should be about 3200ppm of salt (1000lbs into 37kgal), my guess is that your pool is actually quite high in salt. This is just a guess from some guy who has never seen your pool, and I'm not a professional, so take it for what it's worth. However, if you were working properly at say 3000ppm for example, and then had 2 feet of rain over a period of a few months and did some draining off intermittently, you should still be well over 2000ppm, so adding 3200 more to that might really put you quite high. Just guessing. If my math is wrong on this, I'm sure someone will point it out.

I rented a house for 3 years that had a pool with an extremely high salt level, such that the SWG didn't work, and nothing really worked for testing it-- perhaps the Taylor kit, but I couldn't get 2 sources to agree on anything. Then I bought the house, and the pool needed some work, so it was mostly drained and I could start over, so I learned a bit about the problems of very high salt levels. One of the problems with very high salt levels is that many people will still recommend adding even more salt to the pool.

 

[prs]

100 lbs salt in 37,000 gallons would only raise the ppm by 300.

I went salt six months ago and these test strips have worked well for me.

http://tftestkits.net/Salt-Test-Strips-Aqua-Chek-p28.html