Help with Test Results

griego

Active member
Nov 9, 2018
34
Miami
No hill , but 3 miles from the ocean. I found some data online close to my house if it helps .

DESCRIPTION:
Latitude 25°39'03.9", Longitude 80°20'18.0" NAD83
Miami-Dade County, Florida , Hydrologic Unit 03090202
Well depth: 91 feet
Land surface altitude: 12.3 feet above NGVD29.
Well completed in "Biscayne aquifer" (N400BISCYN) national aquifer.
Well completed in "Biscayne Limestone Aquifer" (112BSCNN) local aquifer
 

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
5,411
Northern NJ
None of us can tell you with certainty if you are safe to drain 50% of your pool. I would say the risk is low if you drain 50% and immediately refill the pool. But in an area like FL the risk is there.

@mknauss can explain a water exchange process that keeps the pool full while exchanging old with new water.

Here are some articles to read:

Why Concrete Pools Pop Up Out Of The Ground: Reasons, Problems & When To Worry - Buyers Ask

http://www.pegroup.com/publications/Tech-201305.html

Can Concrete (Gunite) Pools Float? Crazy Pictures
 

griego

Active member
Nov 9, 2018
34
Miami
Interesting point, I wasn't aware of that.. Curious to here how an exchange water process looks like . thx
 

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
5,411
Northern NJ
Interesting point, I wasn't aware of that.. Curious to here how an exchange water process looks like . thx
Copied from one of @mknauss posts:

You can exchange some water without draining.

If you place a low volume sub pump in the deep end and pull water from there while adding water in the shallow end (through a skimmer or into a bucket on a step so you lessen the water disturbance) you can do a fairly efficient exchange. That is assuming the water you are filling with is the same temperature or warmer than your pool water. If your fill water is much cooler than your pool water, then switch it. Add the water to the deep end (hose on bottom) and pull water from the top step.

The location of the pump and fill hose may change if you have salt water, high calcium, etc.
In my pool, with saltwater and high calcium when I drain, I put the pump in the deep end and hose in shallow end. The water in the pool weighs more per unit volume than the fill water from the hose.

Be sure to balance the water out and water in so the pool level stays the same. Also be sure your pool pump is disabled during this process. Once started do not stop until you have exchanged the amount of water you wish.
 

griego

Active member
Nov 9, 2018
34
Miami
I see. So how shall I know how much water I pulled out and to stop , when I am filling it from the shallow end ? Thx
 

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
5,411
Northern NJ
I see. So how shall I know how much water I pulled out and to stop , when I am filling it from the shallow end ? Thx
You can get a flowmeter like discussed here - Got some drainin' to do...

Or you can time how long it takes your fill hose to fill a known gallon bucket and calculate the time it will take. It will not be a problem if you replace more water than planned. Your CYA will be lower and you may need to add some stabilizer.
 

Michaelg90

Well-known member
Mar 10, 2019
56
Orlando
Yes, drain half the pool and fill with fresh water to lower your Cya to around 40.

Once you get get a new fill of water we can start with fresh test results and get it in shape.

Your tablets have acid in them and are lowering your pH. I suggest you stop using the tablets, check your FC daily, and add liquid chlorine as needed.
Question as I read this thread. If you check the FC daily using the F100 kit, the daily reader with PH only goes to 5 and being yellow is quite difficult to read. Are you using the powder test each time? The kit mentioned it comes with only 70 tests of that so are you just refilling or using the PH/FC tester that’s yellow and red until your weekly test which then is powder?

Just trying to get the process down pat. Thank you
 

JoeSelf

Gold Supporter
Jun 18, 2014
474
Glassboro NJ
You want to start with the DPD test in the beginning every day until you get to know your pool. Make sure you are using 10ml samples. After you get the pattern down you can test every other day. You might want to use the OTO test along with the DPD in the beginning to get an idea of what the Yellow color will be at your correct FC/CYA level. Then use the OTO as a quick check when not using the DPD.

As summer comes on you will need to test every day again until you see the new pattern.
 

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
5,411
Northern NJ
Question as I read this thread. If you check the FC daily using the F100 kit, the daily reader with PH only goes to 5 and being yellow is quite difficult to read. Are you using the powder test each time? The kit mentioned it comes with only 70 tests of that so are you just refilling or using the PH/FC tester that’s yellow and red until your weekly test which then is powder?

Just trying to get the process down pat. Thank you
First of all it depends what your CYA is and if your FC target is above 5. In general you have to use the FAS/DPD test to reliably test your FC level. Once you get to know your pool you learn your daily FC loss and can test every other day or so.
 

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