K-2006 arrived - How to interpret numbers

[dickeystorm]

I received my K-2006 test kit and I have run 2 tests. If I'm doing this right my CH and CYA are very high. For comparison The first det of numbers is from July 30 done by the pool store. After reading this forum and the pool school and considering my test results I'm rapidly losing confidence in their readings.

7/30/10
FC 10.0 (I think this is the upper limit of the pool store test, if so this was probably higher)
TC 10.0
CC 0.0
pH 7.5
Hardness 310
Alkalinity(w/stabilizer correction) 99
CYA 70
Copper 0.21
Iron 0
TDS 1400

8/13/10 8pm
FC .6 oops: )
CC .4 (I'm not very confident of this number)
pH 7.6
Total Alkalinity 160 (does the k-2006 adjust for stabilizer?)
Calcium Hardness 525 by the .5 method
CYA best guess 180-200, this was well below the 100 mark on the tube
SI ~.7

added about 90 ounces of 6.15% bleach,

8/14/10 730pm
FC 2.0 oops: )
CC .2 (I'm not very confident of this number)
pH 7.6
Total Alkalinity 160 (does the k-2006 adjust for stabilizer?)
Calcium Hardness 600 by the .5 method
CYA best guess 180-200, this was well below the 100 mark on the tube
SI ~.7

After adding a 182 oz jug of 6% bleach and retesting around midnight
FC 5.5
CC 2 (not sure of this number, light was terrible and I'm a bit color blind in the red spectrum and my wife was asleep )

I could use some advice on what FC level I should target with these numbers. I know I'm low now and that I may need to shock. The pool calculator suggest 14-21. I still don't completely understand the relationship of CYA/FC, my understanding is that I need an FC of 10% of the CYA level and that that is safe to go in. The water is clear and looks pretty good. I have noticed when I brush there is a layer of white on the bottom that clouds up when disturbed, not real thick though.

The CH test gave me the fading result so the last test I used the alternate method which seem to work a little better. Also I plugged the FC numbers in to the pool calculator from the midnight test and the FC numbers don't agree for my pool size, 25000 gal. The previous owner said that was the size, I'm going to measure and confirm as best I can, it's a freeform design. If I plug in 18000 gal the poll calculator is right on with my FC numbers.

Any thoughts are appreciated, thanks.

 

[Bama Rambler]

First a couple of testing suggestions.

Take a pool sample and mix it with an equal amount of tap water then check your CYA number again. Multiply the result by 2. It'll be inaccurate but it'll give you a ball park number.

When performing the FC & CC tests drop the R-0871 in until the sample goes completely clear and then one drop more. Don't count the last drop. That way you don't have to see the color. Clear is the only thing you care about.

There's a sticky under Testing & Balancing on Extended Test Kit Directions

You certainly need to keep you FC at least 10ppm but if your CC of 2ppm is correct you need to shock but it's going to be almost impossible to do so without getting your CYA number down. Tell us where you're located because R/O services are available in some parts of the country and that'll take care of your CYA as well as your high CH. Otherwise you're going to have to drain some of your water.

 

[duraleigh]

Hey, Good morning,

Yeah unless you intend to reduce your CYA and CH by partial draining (that's the best course), you will need to keep your FC up very high into the range you already posted. CYA temporarily "masks" the effectiveness of the chlorine so the more excessive CYA you have (you should be around 40-50) the less effective the chlorine.......hence the need for a higher ppm. Yes, it's safe to swim in that.

YOurs is a common issue and it's hard to bite the bullet sometimes but your only real solution is to do a series of partial drains and refills to reduce both those parameters. What is the CH of your fill water?

EDIT: bama and I are saying the same thing....I forgot about the r/o treatment if you live where it's available.

 

[dickeystorm]

Hi,

Thanks for the replies! I saw the extended test kit directions after I tested. I retested this morning and this afternoon,

FC 5
CC .5

FC 5
CC .5
CYA still off the chart using the dilution method. It came to a point just above the half way point between the bottom of the tube and the 100 mark.

I don't think the CC =2 was accurate based on the latest tests. It looks like I'll need to go ahead with the refill. My fill water tested at 120 for CH. According to the calculator I have to draw down 72% if my volume of 25000 gal is correct. I'm going to measure and recalculate the volume to be sure.

What is the best way to accomplish a refill. I have some spots in the plaster that could use patching so I was thinking I should drain the pool completely, patch the plaster, clean the pool (pressure wash?) and refill. I read a post that cautioned about exposing the plaster to direct sun as it will cause blisters. I'm not excited about doing all that at this time of year since it's peak use time and very hot.

I'm in Lake Jackson, TX, 1 hour south of Houston. Can you give me an idea of how much the R/O service would cost?

Thanks

 

[Bama Rambler]

I don't believe R/O is available in your area. You're left with drain refill. Unless you know that your water table is low I'd recommend draining about half at a time until you get the levels down.