New to me Pool, high FC and CYA

[cmarshall48]

Hey everyone, new pool owner and new to TFP here. I just bought a house with a 9,000 gallon plaster pool, and my chemistry is a bit off. I have a k-2006 test kit but was having trouble getting a FC and CYA reading. I took a sample to Leslie’s and they read the FC as 23 and CYA as 167. These crazy high numbers explain why I was having trouble with the k-2006 giving accurate readings.

Now I understand that to effectively get the CYA down to a reasonable level I should drain and refill the pool, but I live in Phoenix and my plaster is not in great shape. I’m hoping to limp it for a year or so before getting the pool resurfaced so if at all possible I’d like to avoid draining for the time being. Is it safe for plaster in the AZ heat to drain 6-12” and refill? Any other advice on managing these numbers through the summer?

Side note, to my knowledge the pool has only been chlorinated with tabs in a floater, which explains how the CYA got to this level. After seeing these numbers I pulled the floater out and plan to start using liquid chlorine when the FC comes down a bit.

 

[ajw22]

Welcome to TFP.

Use the no drain water exchange described below to lower your CYA…

Draining - Further Reading

www.troublefreepool.com

 

[duraleigh]

Welcome to the forum

Depending on the pool store for reliable test results will quickly get you in trouble. Your own test results are far more dependable. We ignore pool store testing.

What issues were you having with the K-2006?

 

[cmarshall48]

Thanks ajw22, I’ll take a look at that.

Duraleigh, I was not able to get a FC reading with the 2006, I tried 25ml sample with over 150 drops r-0871 and it would not turn clear, so tried with 10ml sample and still wouldn’t turn clear with 80+ drops so I think the FC being really high makes sense. With the CYA test, the dot was invisible before the level reached the 100 mark, so CYA being high also makes sense.

 

[ajw22]

With the CYA test, the dot was invisible before the level reached the 100 mark, so CYA being high also makes sense.

In that situation you do the CYA dilution test...

For CYA > 90ppm, repeat the test adjusting the procedure as follows:

1. Fill the mixing bottle to the lower mark (15 ml line) with pool water.
2. Continue filling the mixing bottle to the upper mark (30 ml line) with tap water.
3. Shake briefly to mix.
4. Pour off half of the contents of the mixing bottle, so it is again filled to the lower mark (15 ml line).
5. Continue the test normally from adding R-0013, but multiply the final result by two.

If you need to dilute the pool water further then apply these ratios:

Pool water	Tap or distilled water	Multiply result by
1	1	2
1	2	3
1	4	5

Note that when doing a diluted test not only do you multiply the range of the test you multiply the error rate of the test, so results are a ballpark - not an absolute.

See CYA Testing for tips in how to read the test results.

 

[cmarshall48]

In that situation you do the CYA dilution test...

Awesome, thank you I will give that a shot!

Another question, hopefully not a dumb one; I have a cartridge filter and I opened it up to clean the filters. They are old and falling apart, so I ordered some Pleatco cartridges. Am I OK to go ahead and replace the filters with my chemistry being out of wack, or will I run the risk of destroying my new filters?

 

[ajw22]

Am I OK to go ahead and replace the filters with my chemistry being out of wack, or will I run the risk of destroying my new filters?

You are fine.

Cartridges can withstand any crazy water chemistry.

 

[cmarshall48]

You are fine.

Cartridges can withstand any crazy water chemistry.

Thanks! Got the filters changed out today and tried the diluted CYA test, I had to go up to 4:1 with tap water to get a reading and based on that I’m seeing a CYA of 300… so I’ll definitely be trying to do a water exchange in the next couple of weeks.