CH >1000 and I Know Why

[geekgranny]

I found a very old huge bucket of Cal Hypo behind the shed that a friend gave me years ago when she moved into an apartment. The plastic was breaking down and had some cracks so water got into over the years. Several nights ago I brought it to the pool area where I have a flood light for working at night and opened it. My plan was to get the 3" of rock hard substance out to throw away (I guess at the toxic substances drop off in Ft. Worth or our annual city drive up collection). I was then going to put the huge bucket in with the recycling. I chopped, hammered, and used anything I could find to try to break it into pieces with no success. It was basically cemented to the bucket. DH called me in to dinner so I just put the top on loosely planning to go back out to continue. Well......... Dinner was great (homemade beef stew and cornbread - I'd probably starve if he didn't feed me) DH had recorded a great movie. No more work for this girlie.

Next day when I went out a bench had blown over from high winds, tumped the bucket over, and it rolled into the pool. <----------- pun intended Most of it had disolved. Filter and sweep had been running a night for leaf pickup and to dissolve CYA I needed to add from letting out three weeks of rain, 15", and frequent backwashings.

My initial reading of CH was > 3000 but Cl was only ~30 so apparently much of the Cl had broken down and/or leached out. Otherwise Cl would have been much, much higher according to the Pool Calculator.

I proceeded to do lots of draining and refilling. I now have it down to a manageable CH= ~1060 with Cl=8

Doing lots of reading these and other posts I think I'm okay for a few days:

http://www.troublefreepool.com/calcite-saturation-vs-calcium-level-for-plaster-protection-t3721.html
http://www.poolforum.com/pf2/showthread.php?p=41165#post41165

and from this posting.php?mode=quote&f=67&p=30349 (my current numbers below quote)

Even in cases of extreme water balance such as very high calcium levels I do not believe that knowing the CSI is that important. What is important in such a case is to keep the pH down and lower the TA. Both these actions will help prevent scaling conditions.

In these extreme CH level cases it often becomes a question of clarifying just how much to keep the PH and TA down. Simply saying to keep PH and TA down is vague and doesn't always result in people taking appropriate actions. Most people would like some guidelines about how far down they need to keep PH & TA for their particular CH level. Playing with various levels and seeing what CSI they give is a handy way to get an idea of how far down PH and/or TA need to be brought.

The chemistry of plaster is complex and it isn't clear that the CSI tracks all of the relevant chemistry exactly in all of the various cases. Still, there is evidence, for examples see some of Chem Geek's references, that it tracks it well enough to use the CSI calculation to figure out some rough PH & TA targets in these cases.

So what I now have:
CSI = --0.03
temp = 68
Cl = 8
pH = 7.2
TA = 80
CH = ~1060
CYA = a little more than 30 (stocking over jet empty [EDIT) that a.m.; started adding earlier that day before incident) [end EDIT] so it will probably be a little higher in a few days ........... except that I'll be letting more water out.

From reading and the above quote it appears that I will be okay for a day or so until I can get more water taken out and refilled. My pH has been pretty steady before this incident needing only small amounts of MA to keep it at 7.5.

I just converted from ionization a few weeks ago and I've been thrilled with water quality and low maintenance (except for our darned silt/sand from puppies swimming). Thank goodness for my Verro 300 (iRobot version of Aquabot Turbo T-jet) as I can keep the pool swept and water circulated no mater the water level. That's why I got it in the first place in 2007 when I had a monster leak.

Have to get some more cellulose for DE filter tomorrow and more reagents and some more CYA to add back in once I get the CH in acceptable range

So from looking at the discussions and specifically the quote above it looks like my numbers are pretty okay for a short period. One thing I'm not sure about though..... Do I keep the pH a little on the low side like 7.2 or do I need to go lower?

Thanks, gg=alice

 

[polyvue]

Do I keep the pH a little on the low side like 7.2 or do I need to go lower?

I think lower is the wrong direction. When I entered your numbers in the Pool Calculator and decrease the pH variable, the Saturation Index moves furthur into the negative. Whether or not you elect to drain some of the pool water to lower Calcium Hardness (I would!) you want your pH to be the same or up slightly.

Of course, a partial drain will affect the other elements and I'd expect you'd have to adjust these as well to restore balance and sanitation level.

 

[duraleigh]

I don't use the CSI but I suggest keeping your pH right where it is.

You're in the "normal" range now and you know what your issue is and you know what to do about it. In essence, you know it's broke but you understand how and why it got broke and, importantly, you know how to fix it.

Higher pH. TA, and CH leads towards scaling so don't raise any of those three (I know you know that....just a point of reference).

Now that you could use it for dilution, it probably won't rain again for months.

 

[geekgranny]

Thanks much guys. I plan on letting out about 50% of the water over the weekend. One of the nice things about having pumping station below pool is that draining is fast and easy via the pumping station. I do have plenty of Cl 6% on hand and a bunch of baking soda and picking up rest of needed today for balancing tomorrow.

Higher pH. TA, and CH leads towards scaling so don't raise any of those three (I know you know that....just a point of reference).

One of the reasons I posted this is for "point of reference" for others who are faced with HIGH CH. After reading the posts from the links supplied, and others, I thought it would be a good reference for anyone who needs info. AND I found out my pools condition is not "deadly" for the pool if other numbers are kept in range.

Boy do I know about scaling. After many, many years of using ionization and not paying much attention to other numbers other than keeping some Cl in pool I have an ample supply of calcium scaling on my pool surface. Last year a friend and I acid washed. We ended up using straight MA on some parts of the walls being careful to keep adequate water running so as to keep the acid washed away from bottom of pool. The steps were so bad I had to get out my angle grinder, with concrete grinder discs (went through two of them), to get the scale off of the steps; well actually only the bottom step as I fell and tore a rotator (shoulder) tendon before I could get to the two top steps. One step took about three hours to grind down. What was left in the bottom of pool we didn't address as much as sides because getting the bottom done is much trickier than sides with more chance of taking off too much of the "plaster" and pitting. My plaster is blue so observing results is easier than if white, and gives a good gauge for when you are not doing enough acid wash or too much.

[EDIT] Following quote is actually duraleigh's. [end EDIT]

Now that you could use it for dilution, it probably won't rain again for months.

Every time I back wash or let water out (and refill) it rains another several inches the next day. No rain predicted for about three days and then more rain. I think the Arizona monsoons have moved to Texas. I can't remember when it has ever rained this much for this long at this time of year and stayed so cool for such a long stretch this early. I'm afeared that Texas is going to float out to sea.

Again, thanks much, gg=alice

 

[polyvue]

Higher pH. TA, and CH leads towards scaling so don't raise any of those three (I know you know that....just a point of reference).

• ...

Now that you could use it for dilution, it probably won't rain again for months.

It's possible that[/color] duraleigh]polyvue doesn't know what he's talking about...

 

[geekgranny]

Higher pH. TA, and CH leads towards scaling so don't raise any of those three (I know you know that....just a point of reference).

• ...

[correction by gg] Following quote is actually duraleigh's. [end correction]

Now that you could use it for dilution, it probably won't rain again for months.

It's possible that[/color] duraleigh]polyvue doesn't know what he's talking about...

 

[polyvue]

Actually, both quotes are his... but I certainly enjoyed the attribution while it lasted! :lol: