Comparing Test Results

[shep377]

So I am still trying to get things running smoothly on the new pool - I cannot wait for the TF-100! (as I can't do a number of tests now)

I did a test of my water myself with the kit on hand, and also took a sample to 2 different pool stores who give a fancy printout of results. The results varied widely! As follows... This is new pool water from city water tower.

Me: (my wee kit until TF-100 gets here)
TC - 1.0
pH - 7.2
T/A - 190
Salt - 3200 (on SWG display)

Store #1
FC - 2.0
TC - 2.0
pH - 7.8
TA - 200
CYA - 50
Solids - 200
Salt - 3100

Store #2
FC - 0.8
TC - 1.0
pH - 7.7
CYA - 30
Cal Hardness - 277
Salt - 2700

The results were... VERY different!

Store #1 said: (for $75 they advise...)
- add 2gal/3pt/15oz of Muriatic Acid, to drop T/A but keep an eye on pH during this.
- add a bottle of scale inhibitor
- add a bottle of algicide
- said FC good, salt good, cya good

Store #2 said: (for $250 they advise...)
- add 1/3 gal of Muriatic Acid daily for 10 days, if T/A falls < 7.2, wait for rise, then continue
- add 5 lbs stabilizer 100 or sunshield
- add 3 bags of Burn Out 35 (clear shock) then don't swim until it returns to 1-3ppm
- add 0.5 gal of scale inhibitor
- add 88lbs salt
- add 0.25 gal of algae inhibitor (polygard)
- AND want me to add 4lbs Mineral Springs Renewal weekly, 2/3 gal Mineral Springs Stain and Scale monthly, 2 bags BioGuard Lite weekly, 12oz of Polygard algae inhibitor weekly, 4oz of Natural Clarifier weekly

My personal opinion is that store #2 is trying to sell a lot! :grrrr: I decided to add a some stabilizer, some M acid. Then retest in a day or two.
Any thoughts or suggestions!!?!

How can stores that are supposed to be experts give such contrary advice? (I suppose that is why I am here learning now)

Cheers

 

[techguy]

My immediate thoughts are:

1. Add some chlorine
2. Add some CYA/stabilizer, since you just filled the water doesn't have any. Do this based on your pool size and the pool caluculatr. I have heard this is best done in stages. If the calculator says 5 pounds, add 2.5 via the sock over the return method and test again in a week
3. Stop going to the pool store and enjoy your Trouble Free Pool

 

[Smykowski]

Techguy has good advice, but I'm going to highlight the most important:

3. Stop going to the pool store and enjoy your Trouble Free Pool

How can stores that are supposed to be experts give such contrary advice? (I suppose that is why I am here learning now)
Cheers

There's a few reasons. First, the testing equipment and computer program is based on who they are an authorized dealer for. The place I used to use was a BioGuard dealer, so everything was based on BioGuard recommendations. Second, most of the employees don't really understand water chemistry. They only understand what the computer says (did I mention the computer was provided by the chemical company?). Third, it's widely accepted around here that test strips are worthless. Highly advanced computers making precise measurements of crappy strips still leads to crappy results.

Go to the pool store for equipment. Go to the pool store for acid and bleach (if it's a good price). Never go to the pool store for water balance advice.

 

[shep377]

Awesome advice. Could it possibly be, in a consumer-based world that we live in, that the pool stores don't have anything by our best interests at heart? That's doesn't _feel_ right... I may be starting to see the light. I await my TF kit...

 

[lightingguy]

If you keep your chlorine levels within the CYA/FC ranges here you will never need the algecide, phosfree and whatever other nonsense they recommend.

The only thing on that list I'd think you'll need on a regular basis is Muriatic acid to help bring the PH down as it rises. If your TA is indeed 200 then that combined with the SWG will tend to push your PH up. Usually you can let it rise to 7.8 or so, drop it down to 7.2, let it rise, drop it down - and over time you'll be adjusting your TA downward.

A gallon on Muriatic Acid is somewhere in the $5 dollar range - and you might use a gallon a month or so (total guess - but ballpark)

Depending on rain overflow, etc you may need to adjust your salt level once or twice a year.

And if you are consistent in monitoring your levels so your FC level doesn't drop too far and your PH doesn't get way out of whack that should be it.

In terms of coming to grips with the disconnect of Pool store/Pool Professional advice and the science based advice you get here, these are the 5 issues I've come to think of as important -

1) 1-3ppm FC is based off EPA drinking water recommendations (No CYA present) - from a liability point of view this is a very easy road to take
2) All forms of solid chlorine contain by-products that build up over time (CYA or Calcium). This is a very inconvenient fact of life that no manufacturer talks about
3) The low FC recommendations also include some sort of weekly "shock" treatment and periodic water replacement. The shock treatments are to kill off the algae that is ever present in a low FC pool, the water replacement to fix the inevitable rise of cya that makes the chlorine increasingly less effective.
4) There are plenty of common pool store ideas that a patently false on their face - Chlorine "Lock" and standard TDS advice come to mind
5) MOST IMPORTANTLY : Until the internet there was no way to compile the collective experiences of thousands of pool owner/operators

Once you put all that together you find a pool service industry that gives rather poor advice (overall) - and has absolutely no economic reason to change. However unlikely that seems at first.

 

[techguy]

I have an excellent LPS, they know how to test the water using the same tests recommended here, Taylor drop tests and a CYA measure using reagents and sliding dot scale.

This year, the only things I have bought there were gaskets for my skimmer, a new return fitting and two small jars of CYA. I have changed over to cellulose in my filter but they have by far the best price on DE. I have also bought some toys there. I did buy my test kit from Pool Supply World, in stock at their retail store. I changed my liner and found a price that was less than half what they wanted for the liner...but they had my size in-stock. That being said, they were the only store (including several web vendors) I called, anywhere that had my liner in-stock... they were just pricey.

I buy my CL and MA at either Wal-Mart or Home Deport (wherever I am at that day, no huge difference in price). WM for the Arm&Hammer and laundry borax.