Starting over after 4 years of trouble

[bbjj109]

OK, we bought this house with the pool 4 years ago. Lived here my entire life suffering through summers. I thought I did the right thing by hiring a pool guy to come and teach me how to maintain it. Probably not a good idea, at least not that guy. And I'll admit, I haven't been the best about maintaining the chemistry. I had been pretty much exclusively using the pucks. The first time I checked the CYA using the Leslie's pool kit, it was off the charts (over 300+).

So, I'm turning over a new leaf. My TF-100 (and magnetic stirrer) arrived this week. The pool is on a SLOW drain (thanks to the Harbor Freight 1/6 HP submersible pump). I have a calcium line around the pool (rolled edge, no tile) and think I'll have them come sand blast it this week. I spent 15 minutes with lime-away and then muriatic acid/water solution and a wire brush and there is no significant difference on a 2-foot section.

Here's my question:

The calcium line has been sand blasted before (4 years ago). The concrete around the pebbles in this area looks pretty deep. Is it OK to sand blast it again? We'll probably do a full remodel in the next couple of years and get rid of the rolled edge and put in tile, so this needs to last a couple more years.

Any other suggestions before I start adding water back this week?

Thanks a bunch for your help!

 

[linen]

I can not comment on your plaster question, hopefully someone will chime in soon

Are you sure your water table is low so that you do not risk floating your pool as you drain?

What is the CH on your fill water? That may be part of the cause of your reoccurring problem with scaling.

 

[duraleigh]

Any other suggestions before I start adding water back this week?

Control your pH, TA and CH. Keep those on the low side of normal (say pH-7.2, TA-90, and CH as low as you can get it) and you probably will not get ANY more scaling.

What is the pH, TA and CH of your fill water? Any chance you can easily refill from softened water? Test accurately, control those three items mentioned above, and I doubt you'll have any MORE buildup. Getting rid of what you have is not easily done through water chemistry.

For what it's worth, your TR100 filter is a 100gpm filter

 

[bbjj109]

Have never heard of anyone in Arizona having trouble with a pool floating when draining. I guess I never considered the issue. And since we are in the desert and in a drought, I'm going to assume it won't be an issue.

Good point on the fill water, but I don't think I can easily fill with soft water unless one of my neighbors has a softener and would let me run a hose from their kitchen sink for a couple of days. I'll get back with you on those measurements.

 

[bbjj109]

And interesting note about the flow rate. The sticker on the side of the filter pretty clearly says 15gpm flow rate.

 

[JamesW]

And interesting note about the flow rate. The sticker on the side of the filter pretty clearly says 15gpm flow rate.

15 gpm per square foot of surface area x 4.91 square feet = 73.65 for Commercial Pools
20 gpm per square foot of surface area x 4.91 square feet = 98.2 gpm for Residential Pools

http://www.pentairpool.com/pdfs/tritonIIDS.pdf

 

[bbjj109]

Latest events: Pumped the water out of the pool. Unfortunately when it was down to about 10", I tripped over the hose and fell in. Pretty bruised and scraped up and feeling pretty foolish, but it could have been MUCH worse. That's a pretty far drop. I had just gotten home and even my purse, phone, everything went in with me.
Hired someone to sandblast the calcium line. I have to tell you he was pretty impressed with my testing kit and stirrer. And he used to work in a water treatment plant!
He was wanting to sell me "start up" service. But when I told him my strategy he said "wow, you've really done your research". I did give you all credit, though. The pool is filled now.
Fill water was
FC 1.5
CC .5
TC 2.0
pH 7.5
T/A 170
CH 200
CYA 0

Added shock and some stabilizer yesterday. This morning's readings:

FC 5
CC 1
TC 6
pH 7.2
T/A 210
CH 200
CYA 15

So, I added a box of borax (another one is waiting in the wings) and I have a sock filled with stabilizer in the skimmer. That stabilizer seems to take days to dissolve. I also have the aerator and waterfall running to bring up the pH.
How am I doing so far?

 

[duraleigh]

Control your pH, TA and CH. Keep those on the low side of normal (say pH-7.2, TA-90, and CH as low as you can get it) and you probably will not get ANY more scaling.

Leave your pH alone. Keep it in the low 7's

Scaling is (simplified) largely due to the above parameters being too high.

CYA WILL take time to dissolve don't bother to test it for another 5 or so days.

 

[bbjj109]

Thanks. I figured adding the borax and bringing the TA down would also bring down the pH. So to offset that, I'm aerating. Do I have that wrong?

 

[linen]

Unfortunately when it was down to about 10", I tripped over the hose and fell in. Pretty bruised and scraped up and feeling pretty foolish, but it could have been MUCH worse. That's a pretty far drop. I had just gotten home and even my purse, phone, everything went in with me.

Ouch, sorry to hear that happened ...how deep is your pool?...though even a fall into a shallow one could be bad

Added shock and some stabilizer yesterday.

What is the shock you are using? Is it dichlor? If it is, that is adding CYA to your pool, so I would probably stop using it and just use bleach/liquid chlorine.

So, I added a box of borax (another one is waiting in the wings)

As duraleigh mentioned you do not want to raise your ph right now, so for the time being do not use anymore borax. It primarily raises ph (and TA a little). Since you already have high ta, you ph should come up on it's own. With that said, since you have scaling problems in the past, you should keep your ph down closer to 7.2.

and I have a sock filled with stabilizer in the skimmer. That stabilizer seems to take days to dissolve.

Often CYA can take a week to disolve and show up in testing, so I would wait a few days to test. How much did you add and what level were you shooting for.

How am I doing so far?

Since you measured 1 ppm CC, I would raise your FC up to shock level and then perform a overnight chlorine loss test (OCLT) to see if you need to do the shocking process. See:http://www.troublefreepool.com/pool-school/overnight_fc_test. If your FC drops by more than 1 ppm overnight or if you continue to have 1 ppm or greater CC, you should do the shocking process (see: http://www.troublefreepool.com/pool-school/overnight_fc_test).

 

[duraleigh]

The 1.0ppm from the CC's test is surely monochloramines from your municipal fill water and can be ignored.

Shock is a process that you do to your pool....it is not a product.

Here's how you adjust pH and TA

pH up - use 20 mule team borax (TA moves but not enough to worry about)

pH down - use muriatic acid (this time TA will adjust downward but this is NOT a permanent reduction of TA)

TA up - Use baking soda (pH will be affected a little but not much)

TA down - This one has everyone confused. You PERMANENTLY lower TA by using the method described in Pool School pool-school/lowering%20total%20alkalinity

Shock is a process that you do to your pool....it is not a product.

 

[bbjj109]

Not deep, but still a big drop to the bottom. All winter long when skimming leaves out of the pool I had visions of falling into the 40 degree water. Glad it was 70 degree water and only 10" deep.

The "shock" (I know, not a product) was 1 lb of trichlor.

Turned off the aerator/waterfall for now. I see where I made a mistake . I had a pH goal in the calculator of 7.5 instead of 7.2 so it was telling me to add borax. Now it looks like I'll have to add acid to drop the TA. Then I'll see what the pH is before proceeding.

I'll do the OLCT tonight/tomorrow and see if I need to shock (the process ).

I added about 1.5 lbs of stablilizer 2 days ago, plus the trichlor. CYA measured 15 after that. Now I have about 2 lbs in a sock in the skimmer. I'll keep doing this until I get it to about 40-50. Once it dissolves/stabilizes (7-10 days?) I want to test to see how much CYA goes up with the chlorine "pucks". On an everyday basis, I'll use liquid bleach, but during the summer if we are away for a weekend, will need to use the pucks periodically.

Thanks everyone for all of your help and advise. It's no wonder I've had so much trouble with the pool for the past 4 years. You don't know what you don't know until you get on this site!

 

[linen]

I'll do the OLCT tonight/tomorrow and see if I need to shock (the process ).

Duraleigh brings up a good point about your fill water. It very well may have monochloramines in it and therefore the 1 ppm CC. How does your water look? If it looks clear then I would not worry about the 1 ppm CC unless it doesn't go away within a day or two.

Don't stop the aeration, it is your friend for now. Follow the instructions in the link duraleigh post for lowering TA. Your will want your TA lower to prevent having any more scaling problems.

 

[duraleigh]

Now it looks like I'll have to add acid to drop the TA.

Don't think of it like that. You add acid to drop the pH. To drop the TA (permanently, which you need to do), you do so with the aeration/acid procedure I linked above.

 

[anonapersona]

I added about 1.5 lbs of stablilizer 2 days ago, plus the trichlor. CYA measured 15 after that. Now I have about 2 lbs in a sock in the skimmer. I'll keep doing this until I get it to about 40-50. Once it dissolves/stabilizes (7-10 days?) I want to test to see how much CYA goes up with the chlorine "pucks". On an everyday basis, I'll use liquid bleach, but during the summer if we are away for a weekend, will need to use the pucks periodically.

CYA is tricky to measure and it sometimes takes a mysteriously long time to register properly, even though the pool will behave correctly based on the calculated addition. That is, FC is less affected by sun and so remains in pool longer.

You can calculate the CYA addition from Trichlor pucks using the Pool Calculator, see Effects of Adding Chemicals, at the bottom. You need to know or estimate the volume of the pool. For example, in my pool of 23K gallons, one 8 oz puck of trichlor will add 1.4 ppm of CYA, and my pool needs about a puck a day if I am using only that for chlorine.

If you are keeping a pool record book (recommended), you can keep a record of what the calculated CYA ought to be. The measured value ought to always be somewhat less since back washing filters or rainwater overflows or splash out all reduce CYA and it also degrades slowly over time (just a few ppm per month). Since I use bleach most of the time, I only test CYA monthly, it doesn't change much.

I don't use pucks much but for vacations. Per the Pool Calculator I get 1.4 ppm CYA/puck so when I fill the in-line chlorinator with 7 pucks I will get about 10 ppm CYA. Therefore before vacation time rolls around I try to keep the CYA levels on the low side, near 30, so I can be gone for 2 weeks (7 pucks a week) and return to a pool at about 50 ppm CYA.