I"m not sure what my readings should be! The more I read the more confused I get!

by Dana Stokes
(New iberia LA)

I have a 20000 gallon plaster salt water pool with many water features. When filter is running overflow from spa into pool.

Also there are also 2 fountains and waterfall on a timer. I have a 4 cartridge filter. I have a Hayward T Cell-15 that is less than 1 year old. I use a Taylor K-2006 C Service complete FAS-DPD and the Taylor salt test kit. I recently cleaned the cell and the filters.

My FC is 3.4 CC is 0.2 my ph is 7.8 to 8 Alk is 130 CA is 220 Salt level is 3000 my cya is somewhere between 60 and 70 I am always fighting a high ph but am told that this is common in salt water pools and also with water features. My cell is set at 45% for pool and 4% for spa. my filter runs 12 hrs a day FYI

I have brought two pool water samples taken at the same time 18 inches deep end of pool into two different pool stores on the same day that use computerized testing and give me different results! These results are also different than my own! I don't feel like I can trust the pool stores in my area.

I feel very comfortable testing my own pool water but find the cy test difficult to interpret. It can be subjective. When the black dot just begins to disappear!

Hi Dana. First, let's say that it sounds like you've had a pool for years without any
issues. You cannot have a pool for a length of time and not know, or understand anything. Experience tells much.

You're using a Taylor kit and know how to use it. You're correct that a salt pool tends to have a higher pH. You also have a plaster pool that adds to the issue. The best remedy is to have several gallons of acid on hand. There's simply no way around it. It's the law of chemistry. We can't change the laws so we must work with them.

You've become empowered to take care of and control your own pool, and that's the best step. Learn about your pool and your situation so you're not subject to someone else.

The CYA is a bit subjective, unlike the other readings. Yes, you look for when the black dot disappears. This could happen quickly, mid-range in the vial, or fill it up all the way and still have clear water so the black dot never disappears.

The black do should disappear about 60% up the vial as you fill it. Again, it is subjective. But there is a huge difference between it immediately disappearing and never, which means the CYA is out of range and needs to be brought back into range.

In your case I'd concern myself with not adding any kind of CYA (tabs or granular) and monitor the situation. Maintain a good FC level of 3 - 5 ppm. Your other readings are fine. And maintain the pH at the correct level.


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