High CYA - Draining and Refilling at same time? Or Best way?

Ejosh87

Well-known member
May 11, 2019
51
Florida
I'm in Central Florida (Orlando area). Plaster Pool.

I have been using a pool company for 3 years but finally started realizing the guy barely does anything and his numbers (CYA, FC, etc all are fake). I received the TF-100 and after multiple tests I believe my numbers are accurate (just not 100% sure since I'm a novice)

FC: 30
CYA: 160
PH: 7.5
TA: 70
CH: 600

Our tap water seems to be 150 ppm Calcium, but that seems really high (although Central FL does have hard water)

I'm thinking I may just bite the bullet and drain the pool (although I don't know if I will be able to do liquid chlorine daily yet with how busy my schedule is at the moment, so maybe 1 trichlor in a floater and then liquid chlorine supplemented?)

A few questions however:

1) Should I just do the drain first and then refill? Is there any danger to this causing the pool to raise/crack/etc? Or do a drain from the main bottom drain and then refill from a hose at the surface if that is easier/safer?

2) Does 150ppm Calcium seem wrong for tap water?

3) Do I need anything on hand or in preparation before I start doing the drain? (i.e. suggested amount of liquid chlorine, muriatic acid, baking soda, etc?). I already have some muriatic acid from over a year ago, sealed well in the garage.

Any other tips or suggestions before I start?

Thank you!
 
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Richard320

TFP Expert
LifeTime Supporter
Jan 6, 2010
22,053
San Dimas, CA (LA County)
The biggest worry is floating the pool. The groundwater is probably pretty close to the surface and you don;t wanbt the pool to raise and break all the plumbing. Take a look: And here what happen with and empty pool and lots of rain

The most efficient way to do it is to empty out whatever and then refill it. But I just showed you what could happen.
I'm sure Marty will be along to explain his in-n-out method.

Anyway, 150 CH is hard, but quite believable if you live in California. I wouldn't worry, though. It's not ideal, but it's not a huge problem to maintain pool chemistry up to about 800 CH. Your killer is the high CYA.
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
20,493
Laughlin, NV
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.
 

Ejosh87

Well-known member
May 11, 2019
51
Florida
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.
I’m assuming no way to do this without a pump? Ie. Just hose and main drain? - main drain and skimmer are both in deep end.
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
20,493
Laughlin, NV
You can use main drain if you like. I just do not like using a very expensive pool pump to do a process that when I am sleeping, something goes wrong and I burn up the pump.

But up to you ---
 
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Ejosh87

Well-known member
May 11, 2019
51
Florida
You can use main drain if you like. I just do not like using a very expensive pool pump to do a process that when I am sleeping, something goes wrong and I burn up the pump.

But up to you ---
Oh ok good point. How much is a pump for this? Or any recommendations. Where to get a cheap decent one for this?
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
20,493
Laughlin, NV
I have a Superior brand 1/2 hp sump pump I bought through Amazon. $90.
You can also find them at Harbor Freight, Home Depot, etc.

If your effluent is through a normal garden hose to your sewer cleanout or street gutter, you will get ~5-7 gpm through the pump.

Once you have the in / out rates balanced, take one of the hoses and fill a 5 gallon bucket while timing it. Then convert to gpm for your situation.
 

Ejosh87

Well-known member
May 11, 2019
51
Florida
I have a Superior brand 1/2 hp sump pump I bought through Amazon. $90.
You can also find them at Harbor Freight, Home Depot, etc.

If your effluent is through a normal garden hose to your sewer cleanout or street gutter, you will get ~5-7 gpm through the pump.

Once you have the in / out rates balanced, take one of the hoses and fill a 5 gallon bucket while timing it. Then convert to gpm for your situation.
Probably stupid question but with the 1/4 hp sump pump doing up to 30 gpm, what makes the 1/2 hp necessary? My pool is 6 feet deep, and the hose will have to run about 100ft to reach the street for drainage.
 

mepot101

Active member
May 25, 2019
30
Orlando, Fl
Ejosh87,
I am also in Orlando, Conway area, my water tests at 110CH.
My house sits up about 6 feet higher than the street, so I wasn't to worried about the pool lifting. I just did a drain and fill over the weekend. I left about 5000 gallons in the pool, that was what I figured I needed to get my cya down, it worked good. My cya went from 150 to ~35. If I'm right, 5000 x 7lbs per gallon makes 35000 lbs holding the pool down.
Might not be the same at your house though, some areas are closer to the water table.

Also, trichlor tabs will bring your cya back up, but I don't know how much.
Good luck.
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
20,493
Laughlin, NV
Probably stupid question but with the 1/4 hp sump pump doing up to 30 gpm, what makes the 1/2 hp necessary?
The stated rates are at 0 head. The hose adds lots of head(pressure loss). You can get the 1/4 hp, will pump 3-4 gpm I would guess.
 

Ejosh87

Well-known member
May 11, 2019
51
Florida
I have a Superior brand 1/2 hp sump pump I bought through Amazon. $90.
You can also find them at Harbor Freight, Home Depot, etc.

If your effluent is through a normal garden hose to your sewer cleanout or street gutter, you will get ~5-7 gpm through the pump.

Once you have the in / out rates balanced, take one of the hoses and fill a 5 gallon bucket while timing it. Then convert to gpm for your situation.
How do you recommend exactly balancing the in and out rates?
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
20,493
Laughlin, NV
Once the effluent is running, then adjust the hose coming into the pool to keep the water level in the pool even. Takes a few minutes and you may have to adjust some over time.
 

53healey100

New member
Mar 2, 2014
2
Missouri City TX
I am about to replace 1/2 of my pool water due to high CYA level after doing the dilution test. If I shut off the pool pumps, shut off the auto fill and put a garden hose to refill in the bottom of the deep end of the pool, as long as the fill water is cooler than the pool water and placed at the bottom of the pool, wont the cooler water being added to the bottom of the pool force the warmer water on top out the overflow at the surface? Why do I need to pump the pool water out at the surface? I will do a bucket test gpm to determine how long I need to run the hose to get the needed volume. Am I missing something in this method?
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
20,493
Laughlin, NV
That will work if your water is low in CH.

How fast you run the hose will depend on how fast the overflow can take the effluent. Were does the overflow water go?
 

53healey100

New member
Mar 2, 2014
2
Missouri City TX
Tap water CH is low. Overflow goes to the street. Tap water is 75 and pool water is 86 at the surface, so I think this will work, just going to take a while. I took a water meter reading before I started so I will know when I have replaced the correct volume. Glad water is cheap in TX! Thanks for your help
 

Ejosh87

Well-known member
May 11, 2019
51
Florida
What do you think between those two options for draining sump pump?


or


Thanks.
 

Ejosh87

Well-known member
May 11, 2019
51
Florida
Ok so tomorrow I'm going to do the drain and start taking over the pool myself. Latest readings show:

FC: 37
TA: 60
Calcium: 575
CYA: 120
pH: 7.5 (meter shows 7.2 however)

I will need to drain 67% of the water and I'm guessing my pool is between 13,000 to 14,000 Gallons. I'm thinking I should just do 75% of 14,000 to be extra safe so 10,500 Gallons.

Tap water will be colder than the pool water.

Pool Water Temp: 84 F
Tap Water CH: 150 ppm

From what you stated above, it seems my best bet is to put the fill hose in the bottom of the deep end & then sump pump in the shallow end pulling from the top step.


Is there any other preparation you recommend ahead of time (i.e. chemicals to have on hand, things to watch for, tests to do, etc)?

Lastly, I also have stains on my plaster, and I did the Vitamin C test and that did remove the stains in the spots where tested. Before I stumbled upon TFP I asked my pool store about this and they said it's easy to remove using ascorbic acid but to wait until after the summer since I have to lower the PPM significantly and keep it low for at least 24 hours, so much riskier to do during the summer weather. Does this make sense? Should I just wait until October-November regarding treating those stains or try doing it right after the drain tomorrow?
 
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