Need to SLAM? And pH Test Question

[dlance]

Howdy all! Longtime lurker, first time poster. We just moved into a home with a pool and I have been getting back into the swing of things...it has been 20 years since I have had to take care of a pool!

So after a lot of back and forth I have my levels just about right (need to lower CYA a little more, TA is a little on the high side but pH seems to be pretty stable). Full numbers from yesterday:

FC: 7.4
TC: 7.6
CC: 0.2
pH: 7.6
TA: 110
CH: 300
CYA: ~55
TDS: ~475
Water is crystal clear...odd green tinted stains/splotches that will not brush off around the pool. Bright white circle around the main drains. And one self-induced rust stain...because I am stupid. :-D


To the questions!

Q1) I did the overnight test last night (9pm) and this morning (6am) with the following result:
FC: 7.4 - 5.8 (delta -1.6)

Per the Pool School, since I lost 1.6 FC overnight I need to SLAM it, correct? If the greenish splotches are algae related is it safe to assume the SLAMing would help remove them? I am aware it could be any numbers of things.

Q2) Is there some secret to reading the Taylor pH tester that comes with the TF-100? Either I cannot distinguish between the shades (which I have always had trouble with) or something is messed up. It always seems to read the 8.0 level. By comparison, my ColorQ seems to be pretty accurate with pH, regularly at 7.6-7.7 and dropping to 7.5 when I add MA. Should I just use the ColorQ as my pH tester and forget the Taylor kit? Any opinions on the Myron-L Ultrapen PT2 for pH testing?


Thanks in advance! This site is amazing! I wish I had this 20 years ago when I knew the pool stores were screwing us but didn't know why!

 

[Suziqzer]

With a drop like that overnight, you certainly do need to SLAM your pool. Use your pool calculator to determine what your shock level is. If the splotches you are seeing are algae, it should remove them. Be sure you are brushing well during the process to be certain you are getting any debris stirred up and sent to the filter.

If the splotches are related to metals, they usually say vitamin C will help remove the stains. I have not had any stains as such, so not experienced with that. Just do be cautious anytime you expose your pool surface directly with any substance so as not to do it too much to damage the surface. Sometimes stains fade over time as well.

I don't have experience with the other tests for Ph, so can't help you there. Maybe you can have someone else help you differentiate between the colors? I always use something white behind the vial to help see the shades better... and be sure you are in good lighting.

 

[woodyp]

SLAM it for sure with that OCLT drop. Your CYA level is probably just fine in Texas summer heat. Don't worry about TA if Ph isn't swinging around much. Try holding a trichlor puck on those green stains and see if they reduce, if so-----organic in nature. Hold your PH tester up against a white background to view it. Welcome!

 

[JohnT]

Welcome to TFP!

If your OCLT loss was measured in the dark both evening and morning, you probably want to consider SLAMing. If sun hit the pool between tests, you are probably okay, but you may want to repeat the test. Normally algae will brush off. It's possible you have staining from algae or leaves, which should go away with sustained higher chlorine levels. You can try scrubbing the stain with a chlorine puck. If the puck removes it, the stain is probably organic. If the puck doesn't remove it, try scrubbing with a vitamin C tablet. If the Vitamin C works, you may have metal staining.

The key to the pH test is to look at how yellow or purple the test is. Any hint of those tells you you are out of range. Orange is better than yellow, but still low. Magenta is better than purple, but still high. When it is a pure red, you are close. An extra drop or two of reagent sometimes makes the solution match the colors on the vial better. I used to look for several minutes, but now I can pretty well tell what the pH is when the first drop hits the water in the vial, so experience helps a lot.

 

[dlance]

Maybe you can have someone else help you differentiate between the colors? I always use something white behind the vial to help see the shades better... and be sure you are in good lighting.

My wife and I both looked at it in all kinds of different lighting and backgrounds. Every test it turned the 8.0 color. My thinking is if it was truly that high we'd have some eye irritation but we don't. It is the best any pool water has ever felt on my eyes...even my daughter doesn't complain about it and that is a big thing!

The key to the pH test is to look at how yellow or purple the test is. Any hint of those tells you you are out of range. Orange is better than yellow, but still low. Magenta is better than purple, but still high. When it is a pure red, you are close. An extra drop or two of reagent sometimes makes the solution match the colors on the vial better. I used to look for several minutes, but now I can pretty well tell what the pH is when the first drop hits the water in the vial, so experience helps a lot.

Extra reagent doesn't mess up the test? I may try that. The five tests I have done with this kit so far all turn the same color as the top one (8.0 I think).

 

[dlance]

Welcome to TFP!

If your OCLT loss was measured in the dark both evening and morning, you probably want to consider SLAMing. If sun hit the pool between tests, you are probably okay, but you may want to repeat the test. Normally algae will brush off. It's possible you have staining from algae or leaves, which should go away with sustained higher chlorine levels. You can try scrubbing the stain with a chlorine puck. If the puck removes it, the stain is probably organic. If the puck doesn't remove it, try scrubbing with a vitamin C tablet. If the Vitamin C works, you may have metal staining.

Thanks for the welcome!

Definitely no sun. It was dark last night when I tested and the sun was still down over the horizon this morning. I'll have to do the SLAM then. I mainly wanted to confirm there were not any caveats to the 1ppm rule if testing was done properly.

When you say scrub the stain and if XX removes it...how long are we talking about scrubbing and then waiting for a result? Is it quick or and overnight reaction? Guess I'll need to go get some pucks.

 

[jblizzle]

Welcome to TFP!!!

You can try one less or one more drop and see if that helps. It changes the saturation, but not really the color.

Here is more info:
extended-test-kit-directions-t25081.html#p206394

Try the trichlor or the vitamin C for a few minutes ... and you should see an affect with one of them ... although seems silly to buy pucks only for this reason. I would suggest trying the Vitamin C ... if that does not work, assume it is organic and just go with the SLAM process and some brushing should get rid of the stain.

 

[JohnT]

My thinking is if it was truly that high we'd have some eye irritation but we don't. It is the best any pool water has ever felt on my eyes...even my daughter doesn't complain about it and that is a big thing!

There are reports that high pH is easier on the eyes than normal pH.

Often, the cause of eye irritation is low salinity. "New" water seems to be harder on the eyes than "old" water because it tends to draw salt out of your eyes making them feel dry. Chlorine adds salt to the water which builds up over time to make the water easier on the eyes.

 

[dlance]

My thinking is if it was truly that high we'd have some eye irritation but we don't. It is the best any pool water has ever felt on my eyes...even my daughter doesn't complain about it and that is a big thing!

There are reports that high pH is easier on the eyes than normal pH.

Often, the cause of eye irritation is low salinity. "New" water seems to be harder on the eyes than "old" water because it tends to draw salt out of your eyes making them feel dry. Chlorine adds salt to the water which builds up over time to make the water easier on the eyes.

Fair enough. I think I will have to practice with the Taylor more and rely on the ColorQ for actual results. The ColorQ numbers move where I expect them to after adding MA.

 

[ping]

If the pH is reading 8.0 it could actually be higher than that and adding some acid might not change the pH enough to see any difference in the test. The main thing is to trust your test results and it seems that the ColorQ results are more accurate for you.

You might try lowering the pH to 7.2 with the ColorQ test result and see if the Taylor starts to get a result that you can read. Plus, if you decide to SLAM the pool you want the pH down around 7.2 to start the SLAMing.

If you have scaling on the plaster or any white build up on the tiles then I would probably trust the Taylor test and go by that.