How much water do I need to drain?

[flydog2]

I have an Intex 20' x 52". Bought the house in Dec. The pool was a mess at that point.

Before I joined I started reading here I didn't know why I kept getting Algae to grow on the bottom of my pool with clear water. I did all kinds of stuff in the past no knowing that my CYA was high or even what CYA was. I just got my full test kit today but I had a strip kit that showed my CYA was over 150.

Here are my results from today with my new kit:
FC: 5.8
pH: 7.2
TA: 90
CH: 220
CYA: 95 :-(

How much water should I drain to get the Dang CYA down? Yes I have been using those Dang Clorox pucks. That is what the previous owner was using. I did one drain that got me to 95 last night and filled it today to those values.

My plan is to SLAM once the CYA is lower.

 

[proavia]

Do a diluted CYA test.
Anytime the CYA is 90 or greater, a diluted CYA test is warranted.

It isn't possible to read a CYA of 95. The tube sacle is logarithmic, not linear.
If it reads above any numbered line, round up.

 

[flydog2]

I drained and filled almost half of the pool last night into today to get these readings:

FC: 2.0
TA: 90
pH: 7.4
CH: 170
CYA: 70.

I am off to buy lots of liquid chlorine to start a SLAM. MY original CYA must have been through the roof.

 

[proavia]

MY original CYA must have been through the roof.

That's why it was recommended to do a diluted test for the CYA.
A viable CYA reading is needed to know how much to drain.
Getting the CYA down to 50 may have been better - but it's at70 now and still doable.

Reduce your pH to 7.2 BEFORE starting the SLAM.
Don't test pH during the SLAM as the pH test is not valid with FC > 10.

With a CYA of 70, your SLAM Process FC level is 28.
It will take a lot more chlorine to initially get to FC 28. But should (more or less) take about the same amount of chlorine to maintain that FC level.

Plan on dosing the pool to FC 28 (for CYA 70) as least 3 times daily.
Keep us updated on your progress.
Ask any questions you may have along the way.
Don't try to shortcut the SLAM Process.

 

[flydog2]

I had actually drained the pool a fair amount (over 1/3) once before my 100 reading. I hadn't received my real test kit yet but I had a test strip that showed it being off of the charts so I knew what my issue was going to be.

I used the calculator to get the recommended FC levels and I have added the necessary Liquid Chlorine just around an hour or so ago to get started.

 

[flydog2]

Still SLAMing.

 

[V___25]

SLAMing with a CYA of 70 is going to be tough but if you're committed to it, it will work. How does the water look now? What are your current test results?

 

[flydog2]

SLAMing with a CYA of 70 is going to be tough but if you're committed to it, it will work. How does the water look now? What are your current test results?

Still slamming. The water looks great but I keep getting growth on the bottom. It is a sunny hot day here today so she is eating up some free chlorine. Should I check my CYA again today? I haven't checked anything but FC since I got the PH down to 7.2 and started the SLAM.

 

[dBsooner]

Still slamming. The water looks great but I keep getting growth on the bottom.

You're doing great! keep going! Do you have a picture of the "growth" on the bottom? Might be dead algae, which is a good sign.

Should I check my CYA again today?

Did you check it after you replaced some of the water? Or was the 70 after? SLAM'ing at 70 is going to be pretty hard and expensive. You could do a no-drain water exchange to try to get more of the CYA out of the pool.

I haven't checked anything but FC since I got the PH down to 7.2 and started the SLAM.

As you shouldn't FC and CC are the most important numbers during the SLAM. All you need to test. And keep that FC up as often as practical. Some even do test and dose every couple hours.

Good job so far!

 

[flydog2]

You're doing great! keep going! Do you have a picture of the "growth" on the bottom? Might be dead algae, which is a good sign.

Did you check it after you replaced some of the water? Or was the 70 after? SLAM'ing at 70 is going to be pretty hard and expensive. You could do a no-drain water exchange to try to get more of the CYA out of the pool.

As you shouldn't FC and CC are the most important numbers during the SLAM. All you need to test. And keep that FC up as often as practical. Some even do test and dose every couple hours.

Good job so far!

It may be dead algae. It basically disintegrates with any movement next to it.

70 was after several big water changes. It had to have been through the roof before I started this process and had obtained a good test kit. My original plan was to have a local guy I knew take care of the pool for me but I quickly learned he didn't know much at all about water quality.

I have been trying to at least test and dose 3 times a day. Most days have been 4 or more.

 

[dBsooner]

It may be dead algae. It basically disintegrates with any movement next to it.

Yeah. Kinda looks like dead algae, but hard to tell. Usually dead algae is gray in color. Poofing into nothingness can indicate algae too.

70 was after several big water changes.

If you can get lower, it would help you not have to maintain such a high FC level. At 70, you are needing to be at 28 FC for SLAM. I bet you're putting a lot of LC into the pool right now due to the sun eating it quickly too.

My original plan was to have a local guy I knew take care of the pool for me but I quickly learned he didn't know much at all about water quality.

Good call doing it yourself. You'll end up really enjoying it.

I have been trying to at least test and dose 3 times a day. Most days have been 4 or more.

Perfect. Just making sure you were doing it at least 3 times a day. Good job!!

Keep that brushing going, keep that FC up. Every time you add LC, brush. Doesn't have to be a thorough scrub every sq inch brush, but enough to get the walls and bottom stirred up. Get that algae up into the water column where the filter can do its job.

 

[flydog2]

It think it is gray in color.

The part about brushing when added in LC is good to know.

1 gallon today of LC between 10 am and around 2:30.

 

[proavia]

What SLAM level FC are you shooting for?