Maybe a stupid question on water test source, but...

[ITR]

Hey guys...this may be a stupid question...but I thought I would ask it anyways:

When performing my tests (both weekly and daily) does it make a difference if I test from the pool or the spa? I am a tad on the lazy side (and frankly my knees aren't what they used to be) and am wondering if I can just test from the spa since it is elevated and much easier to get "elbow deep" samples. My thought is "water is water"...and I run the pump with the spillway overflowing...but you guys are the experts.

 

[JamesW]

It would probably be better to test from the pool away from returns to avoid errors due to return water that is different from the main bulk of the water. For example, heating, ozone, chlorine etc can change the water chemistry and the return water won't match the bulk water.

Due to the small volume of the spa, it will be more affected by the return water.

 

[pwrstrk]

I agree I would get the sample from the bulk pool water.

 

[JamesW]

You could get a sample bottle. That way, you can get the sample and then do the tests somewhere comfortable, like a table. You could use a gripper device to hold the sample bottle so that you don't have to bend down.

Note: Don't use a glass container for the sample.

 

[ITR]

Well I guess it wasn't a stupid question...

I do have a problem though. New pool (three weeks old). I have been chasing a rising pH due to the new plaster but was seriously surprised this morning. Yesterday afternoon the pH reading was 7.3 (PB recommended to keep it at 7.2 to loosen some calcium build up until he could get out here next week). I did not add any acid yesterday at all. This morning's readings are totally "not normal" (at least for me and this pool):

FC: 6 (no change)
CC:0 (no change)
pH: 7.0 (both Phenol Red test and pH stick)
CH: 375 (previously measured 425...so I was surprised it went down so I did the test twice)
TA: 30 (was 40 a week ago)
CYA: 50 (no change)
Water Temp: 61
CSI: -1.22 (yikes!)

The water feels very "scummy"...like when you have soap and hard water. It did rain last night and there has been a week or so of pollen which I can now see on the tile just above the the waterline..which leads me to believe there was some evaporation happening. The spillway is a bit bubbly as it hits the water as well.

So here are the questions:

1) Should I go out and get some borate to raise the pH right now?
2) Why would CH go down?
3) How do I get rid of that scummy feel?

Any other advice is welcome. I can't thank you guys enough to helping us new guys out.

JB

 

[JasonLion]

1) Probably not. If you are trying to "loosen some calcium build up" you want the PH around 7.0 to 7.2. If all of the calcium buildup has vanished, then raise the PH.
2) There are a couple of ways CH can go down, though the only one that would make any sense here would be water replacement. CH would go down if there was calcium scaling happening, though I can't imagine any way that could have happened. Another possibility is testing error of some kind.
3) Hard to say. Most likely it will clear up on it's own in a few days.

 

[JamesW]

For the pH and TA to go down, something acidic probably was added, unless it's test error. What chlorine is being added?

 

[ITR]

For the pH and TA to go down, something acidic probably was added, unless it's test error. What chlorine is being added?

It rained...using trichlor right now for the Chrlorine. No idea what the acidity of rain water is here in central FL.

Is pollen acidic?

And thanks Jason...as always your advice is greatly appreciated!

 

[JamesW]

Trichlor is acidic and will lower pH and TA. I would suggest watching the TA and not letting it get too low. As long as your TA isn't too low, the pH should not get too low. If the pH dips below 7.0, bump up the TA a little.

How is the trichlor being added?

Has algaecide, sequestrant, or bleach been added?

 

[ITR]

Trichlor is via tabs in what I call an "auto-chlorinator"...not sure what the real term is, but it's a tube that holds the tablets by the pump. I haven't added any since the PB did the startup and added three himself as I am planning to switch to bleach.

Oh, and no algaecide or bleach has been added yet.

 

[JamesW]

The trichlor explains the pH and TA drop. The bubbles are usually due to some type of surfactant such as soap, some types of algaecide, non- regular bleach etc.

The calcium drop could be from test error, fresh water, copper interference, and possibly sequestrant if added. A speedstir can help get more consistent test results.

 

[ITR]

I have a speedstir...and love it! I'll keep an eye on it. Thanks for your help everyone!

 

[tim5055]

Trichlor is via tabs in what I call an "auto-chlorinator"...not sure what the real term is, but it's a tube that holds the tablets by the pump. I haven't added any since the PB did the startup and added three himself as I am planning to switch to bleach.

Oh, and no algaecide or bleach has been added yet.

Skip the algaecide, it's just a way for the pool store to increase their profits in most cases. Keep you r FC where it needs to be in relation to your CYA and you should not have algae problems.

High % liquid chlorine is usually available in most areas of FLA, so compare pricing before you just hump bleach bottles from WalMart. A Stenner pump makes regular dosing with liquid chlorine products easy.