How deep?

[Richard320]

How deep should I draw my test sample?
Taylor test kits say

7. Obtain samples 18" below water surface.

TF Test kits say

6. Collect all your pool water samples about a foot under the surface.

I understand that the surface water is going to have oils and pollen and such which could affect the tests. I've been using a piece of PVC pipe like a pipette and draw the sample from a couple inches off the floor in the shallow end, maybe 30" below surface. What's the difference between 12", 18", and 30" from the top? Do the chemicals stratify or something?

 

[mas985]

It shouldn't matter too much as long as you take a sample while the pump is running or shortly there after. If the water has been idle for too long then there could be some difference by depth, especially on a hot sunny day. I usually will just go a foot down with an upside down bottle, turn it right side up to take the sample but half way or more into the pump cycle.

 

[polyvue]

How deep should I draw my test sample?
Taylor test kits say

7. Obtain samples 18" below water surface.

TF Test kits say [quote:309fboyu]6. Collect all your pool water samples about a foot under the surface.

I understand that the surface water is going to have oils and pollen and such which could affect the tests. I've been using a piece of PVC pipe like a pipette and draw the sample from a couple inches off the floor in the shallow end, maybe 30" below surface. What's the difference between 12", 18", and 30" from the top? Do the chemicals stratify or something?[/quote:309fboyu]Mark's answer makes sense to me. I think the only difference between test kit instructions is the author... Dave appreciates the fact that often "close enough" is... well, close enough. Taylor probably conforms to the aquatics industry standard. I've often seen papers that instruct you to fetch the sample "elbow-deep" (everyone knows that human forearms are all exactly the same length!)

More commonly, the instructions I've read that apply to commercial pools place more emphasis on taking multiple area samples (deep end, shallow end and middle, for example) whose test results are averaged together to approximate the entire pool, and instructions that detail how samples should be capped (no air) and chemically treated for presumed off-site testing.

 

[JasonLion]

The one thing you don't want to do is to take a sample from right at the surface. There is a thin layer of water right at the surface that has had far more interaction with floating debris than the rest of the water in the pool has. Also, the top several inches of water have been affected by sunlight far more than the rest of the water has.

 

[Ohm_Boy]

I have always used "elbow depth" as a guide, but I really try to reach as deeply as I can without soaking my sleeve.

 

[257WbyMag]

What OhmBoy said . Just make sure that the pump is circulating water.

 

[New2Me]

All that wet work when it's cold out is no fun! If you have a Hayward off-line Automatic Chlorinator installed, then you install a tee and a little ball valve in the feed line. Then when ever the pump is running and you want to test the water, you open the valve, purge the line, then fill your bottle, easy-peasy! If you didn't have the chlorinator, you can just drill a hole and mount the valve. No dipping necessary!

 

[Brentr]

All that wet work when it's cold out is no fun! If you have a Hayward off-line Automatic Chlorinator installed, then you install a tee and a little ball valve in the feed line. Then when ever the pump is running and you want to test the water, you open the valve, purge the line, then fill your bottle, easy-peasy! If you didn't have the chlorinator, you can just drill a hole and mount the valve. No dipping necessary!

Not sure if I would want to do any drilling into a perfectly good PVC pipe :-D , but if that works for you go for it I would opt to stick my hand in the cold water

 

[Ohm_Boy]

Keep a 4-foot length of PVC near the pool, and when you want to collect a sample, cover one end of the pipe with your hand, poke the other end into the pool to a foot or 18 inches or so, release the top end to allow the pipe to fill, then cover it again, lift and retrieve a sample 'slug' of water. Dump it into your sample container, and there you are/Bob's your uncle/boom goes the dynamite/presto!

 

[zea3]

I prefer a length of clear plastic tubing (like is used in aquariums) with a fishing weight attached to one end. I use a infant nasal aspirator to siphon water into the tube. Once the water is flowing, fill up your container. Most of the time the water is warm enough to just shove the bottle down elbow deep but if you don't want to stick your hand in it works great! It is also handy for having the vertically challenged family members get the sample from an above ground pool!