CYA Test Question

MbPinter

Member
Jun 16, 2024
5
Grand Blanc, MI
I have been battling high CYA, ph bounce and chlorine issues all summer. I keep getting clumps of brown algae on the ramp to the deep end and along seams. I treat by shocking, adding yellow out and vacuuming to waste. I had stopped using chlorine tabs and am using only CAL-HYPO and liquid chlorine. I had the CYA down to about 60 and tried tablets again in the floater again. I put it in and the next day I found it on the bottom of the pool with the top off. Not sure what happened, but when I tested the water that day, the CYA was 100. Could the CYA jump up that much overnight?? I'm wondering if I'm not reading the test correctly. Do I read it when I can no longer see the black dot at all? The test says "until the black dot just disappears". Thanks in advance!!
 
Mix the solution. Stand OUTDOORS, sun to your back. Fill to the first line, hold the the vial at the top with your index finger and thumb, hold at your waist in front of you, in the shade of your body. GLANCE at the vial, down the tube. If the dot is obscured, then take the number at the line and add 10. That is your CYA level. If not obscured, fill to the next line. Repeat the process, by filling the vial to the next line until the dot is obscured. When it is obscured (see pic below), take the number next to the line and add 10. That is your CYA level.

1721455245501.png
 
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Mix the solution. Stand OUTDOORS, sun to your back. Fill to the first line, hold the the vial at the top with your index finger and thumb, hold at your waist in front of you, in the shade of your body. GLANCE at the vial, down the tube. If the dot is obscured, then take the number at the line and add 10. That is your CYA level. If not obscured, fill to the next line. Repeat the process, by filling the vial to the next line until the dot is obscured. When it is obscured (see pic below), take the number next to the line and add 10. That is your CYA level.

1721455245501.png
So the black dot should not be visible at all through the solution, correct?
 
Correct...you glance. If you cannot see the dot you are done. You might see some black something, you know it is a dot, but you cannot see it.
 
Correct...you glance. If you cannot see the dot you are done. You might see some black something, you know it is a dot, but you cannot see it.
Also, try not to be fooled by the silhouette of your head against the sky, reflected on the surface of the test solution. I'm a little embarrassed to admit that it took me a couple months to realize that that wasn't a barely visible black dot.
 
My sand filter always reads between 23-26. I know this is high, but I'm not sure how to lower it. This is the second summer with a new sand filter. Could this mean I have an algae infestation? My water is always clear, but I have had repeated issues with powdery, brown clumps (assuming this is mustard or brown algae). I brush and shock, when clumps reappear a light beige color, I vacuum to waste, backwash, rinse and within a week, the clumps are back. This has been going on for 2 months. Our pool does not get a lot of use. I've been struggling with high CYA, maintaining the appropriate chlorine levels and PH bounce. I've always used a floater with chlorine tabs, but when our CYA was reading at 100, I stopped using them and went to CAL-HYPO and liquid. Could the pressure be indicating that the filter is not able to clean completely?? And that is why the pressure is so high? I'm at a loss.
 
First, you need one of our recommended test kits. Link-->Test Kits Compared

If you don't have one, add 5ppm of liquid chlorine a day, nothing else.

When you get the kit, or if you have one, post a full set of results; FC, CC, pH, TA, CH and CYA.

If CYA is high, then we need to replace water before you SLAM.

With visible algae, If you have a kit, or when you get one, and your CYA is 70 or below start the SLAM process. Link-->SLAM Process

If your CYA is above 70, replace water before SLAM.
 

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Mb,

What happens after you backwash the filter?? Does the pressure drop, but then after a day or so, it goes right back up again?

If so, then that sounds a lot like algae. You can certainly have algae in a clear pool, by randomly dumping in enough shock to temporarily kills most of it.. But, this will never kill it all.

The best way to confirm if you have algae is to perform an Overnight Chlorine Loss Test (OCLT) Overnight Chlorine Loss Test

If you have algae, you will need to do what we call a SLAM..

Thanks,

Jim R.
 
First, you need one of our recommended test kits. Link-->Test Kits Compared

If you don't have one, add 5ppm of liquid chlorine a day, nothing else.

When you get the kit, or if you have one, post a full set of results; FC, CC, pH, TA, CH and CYA.

If CYA is high, then we need to replace water before you SLAM.

With visible algae, If you have a kit, or when you get one, and your CYA is 70 or below start the SLAM process. Link-->SLAM Process

If your CYA is above 70, replace water before SLAM.
I have one of your Taylor test kits.
 
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