Dealing with scale problem

[PoolDoc]

Aeration strips carbon dioxide, which raises pH. But aeration LOWERS 'carbonics' => carbon dioxide + carbonic acid + bicarbonate + carbonates.

Essentially, alkalinity is that fraction of the 'carbonics' that is present as bicarbonates or carbonates. You can't easily remove those. BUT if you lower the pH, you shift some of the bicarbonates and carbonates into the form of carbonic acid + carbon dioxide.

In your case, reducing the alkalinity enable your pool water to begin dissolving the scale. But that, in turn, replenishes the alkalinity, and increases the calcium.

Since you're leaving for a few days, I'd re-orient the eyeballs to reduce aeration, let the pH drift up to a stable plateau, raise the chlorine level -- and then restart the process once you return.

Brushing 2x per day probably doesn't hurt anything, but it probably doesn't help that much, either. Once a day, or even once every 2 days is probably enough. It's unlikely the dissolution process is moving fast enough to warrant a 2x per day brushing.

Losing chlorine could be a result of dissolving some of the algae capsules, and exposing oxidizable algae to the chlorine.

I'll look at your chart data, and update your pool sig. info.

[beaverplt]

I received my new kit today. Here are the numbers I got
FC 7.6
CC .8
TA 150
CH 250
CYA 42

Weekend prep is done. I'll add chlorine tomorrow to raise levels to last through the weekend. I may not make any progress on the scale, but I don't want to give any algae a chance to come back.

[PoolDoc]

Use this chart to enter your test results; go ahead and retest today and complete the chart. I entered the results above.

http://pool9.net/pf-hist-form/

You can see the results here:

http://pool9.net/pf-hist-chart/

Also, if you haven't yet done so, please complete the pool chart data, here:http://pool9.net/pf-chart/


Enter the thread number (24064) as needed:

http://www.poolforum.com/pf2/showthread.php/24064-Dealing-with-scale-problem

I merged your threads -- they are separate problems, and we've been wasting time giving you the same advice in two threads.

[beaverplt]

Thanks for merging the threads I had been hopping back and forth to re-read both.

Back from my weekend away. I had not been home since I read your last post. I tested the water and entered the results on the form you linked. I was pleased to see the pool is very clear. I also cleaned the filter bag on my Dolphin as I usually do before running it and was very pleased to see handfuls of scale from the last cycle. I seem to be making progress. I believe the correct next step is to lower PH to 7.0 again, reorient the eyeballs to riffle the surface again. I'll continue with your program for the next week or so and continue posting results on the chart.

[PoolDoc]

Thanks!

[beaverplt]

Hi again,
I've been following the program you've recommended and it's definitely working. I can see progress every day as brushing and running the pool cleaner are both removing scale, slowly, but surely. A couple of questions;
1. Should I be running my filter pump 24/7? I cut it back to 10 hours a day and am not sure if I should have done that.
2. I'm testing PH and chlorine levels twice daily. Is that enough? Is once a day ok?
3. How often should I test TA and CH? They've both stayed the same over the past week.
Thanks

[PoolDoc]

1. 10 hours per day is probably OK -- but make it (2) 5 hour sessions, not 10 straight.

2. Once is fine.

3. CH isn't going to change unless you add calcium, begin using cal hypo, or add so much bicarb or soda ash that you cloud the pool. TA -- if you are going to keep the pH low enough to strip carbonate alkalinity, you probably want to test more than 1x per week.