Problems with Aquarite measurements not matching test strips

CMTAinFL

New member
Jul 21, 2021
3
Tampa, FL
Hello! I have an Hayward Aquarite with a T-9 cell. It was installed brand new when the pool was built in September 2020. The pool is just under 9000 gallons.

Currently, the unit is reading a salinity of 3400 ppm. But when I get the salt tested at the pool store and with home test strips I am getting very different readings. On two subsequent days at two different store, the salinity measured approx. 2500 and 2700 ppm. My test strips are reading 2600 ppm.

I'm new to the forums but here is some info that i have seen requested in other threads with readings.

Readings when I switch from auto to off:

3400
88
30.9
0
30
-0
al-0
r 1.59
t-9

Readings when I switch from off back to auto:

3400
88
30.9
4.98
30
-3400
al-0
r 1.59
t-9

Readings when i switch off for 1 minute and turn back on.

3400
88
30.9
4.92
30
-3300
al-0
r 1.59
t-9

other info: the reason i was at the pool store in the first place is that i have been having problems with algae and keeping the chlorine levels up. when the water was tested my CYA was very low (lots and lots of rain in this area of florida lately, so not surprising). I'm in the middle of the algae treatment, shocking, and getting everything balanced process now but one of the things flagged at the pool store was low salt. Prior to going to the store and checking the salt, i didn't specifically check the reading on the box but if i remember correctly it was was reading about 2900. could the shocking/algae treatment be messing with the salt reading on the unit? about two weeks ago I actually had a low salt light (2700 ppm) on the box and i took the opportunity to do a cleaning/acid wash with the cell and then added 40 lbs of salt. the reading after that was about 2900. it seems strange i haven't added salt since then but the reading is still higher than it was two weeks ago. The cell/pool is not even a year old yet so it doesn't seem like there should be an issue with anything yet.

Thanks for the advice!
 

AK-

Gold Supporter
May 11, 2021
364
Randolph, NJ
Pool Size
7000
Surface
Vinyl

CMTAinFL

New member
Jul 21, 2021
3
Tampa, FL
The pool store measured my CYA at 32. I have this test kit: https://www.amazon.com/gp/product/B004BGF7TI/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1 (Taylor k-2006). That kit has the reagents to test CYA. the lowest it will measure is 30 ppm and it i didn't register any CYA with my test kit.

Any thoughts on why the salt on the generator would have measured 2900 a few days ago and now measuring 3400? Could the shocking/algae treatment be effecting it?


Signature info. i'll make one next:

  • The size of your pool in gallons - ~9000
  • If your pool is an AG (above ground) or IG (in ground) - IG
  • If it's IG, tell us if it's vinyl, plaster/pebble, or fiberglass - gnuite pool
  • The type filter you have (sand, DE, cartridge) - DE
  • If you know, tell us the make and model of your pump and filter. - hayward DE3620
  • List other known details of the pump - Horsepower, Single speed, 2 Speed or Variable Speed - Hayward Super II Pump
  • List any other equipment you have: SWG, second pump, etc. - SWG Aquarite t-9
  • List what test kit you use to test your water - Taylor K-2006
  • Please mention if you fill the pool from a well or are currently on water restrictions
  • Note if your pool is indoors or in a screened enclosure. - screened in.
 

CMTAinFL

New member
Jul 21, 2021
3
Tampa, FL
the salt measurement is really throwing me. i can only assume the algae treatment (diammonium sulfate) is messing with the salinity reading on the actual unit though i'm unclear why it would be off on the aquarite but not the pool store unit? I don't want to add salt unless i'm sure i need it and I don't trust the pool store readings, which is why i went on 2 different days and used the test strips (new unopened bottle). i'll order the k-1766 though.
 

AK-

Gold Supporter
May 11, 2021
364
Randolph, NJ
Pool Size
7000
Surface
Vinyl
TFP does not recommend the use of algaecide (exception to Polyquat 60 in very specific scenarios) as chlorine alone should take care of algae. Having sulfates in your water may lead to formation of gypsum scaling of your CH is high and copper bases algaecide may cause staining and hair/nail green tinting.

I can’t really answer the question about SWCG is reading low salt, but I’m sure some other member will be able to help you with that.

Your CYA is too low, so it is likely your FC is going dangerously low and allowing algae to grow. On a SW system you need to bring it at least to 60. Use PoolMath to calculate how much you need and to avoid overshooting add half of it, wait couple days and retest before adding the rest. Use the sock method: Hang an old sock (free of holes) with the stabilizer in front of a return and squeeze it every once in a while).

If you haven’t done so yet I recommend reading ABCs of Pool Water Chemistry and other articles at Pool School - Trouble Free Pool
 

AK-

Gold Supporter
May 11, 2021
364
Randolph, NJ
Pool Size
7000
Surface
Vinyl
Actually before you raise your CYA… How the water looks like? Is it clear?

Would you be able to perform a Overnight Chlorine Loss Test?

You mention the use of algaecide… If you have algae you will need to follow the SLAM Process. If SLAM is necessary then you need to increase the CYA to about 40 before starting.