Trouble Maintaining FC Levels

[tim5055]

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[iammikeb]

@KlearWaterKyle Do you remember which pump you rented? I just gave them a call and their rental dept. wasn't very knowledgeable about how many GPH the different pump offerings were capable of.

 

[iammikeb]

@KlearWaterKyle It looks like the one close to me has these two options:

• Submersible Sump Pump (60 GPM)
• Gas Pump (210 GPM)

Not a huge price difference but if you got those results from the 60 GPM sump, I will save the $30. Also, I can buy an equivalent model for about the same price as renting.

 

[Oly]

Rent the gas pump. I used one and it emptied my pool in 6 hours.
Wash out the suction hose before you put it into your pool, you don't know where it's been.

I bought a 1/6hp pump Everbilt 1/6 HP Plastic Submersible Utility Pump-SUP54-HD - The Home Depot and use it on the pool steps to take the water level down several inches after big winter rains and to drain my spa. It would take days to drain my pool with it especially as the water level dropped.

 

[iammikeb]

It has begun!

 

[iammikeb]

Alright, the pool is filled back up and the results are in (see this morning's test results below)! The only number that moved in a worse direction is the TA, but I am not too concerned with that. I will continue to raise pH (aerating), and lower the TA & pH together to get the TA down to about 70. That process will take some time, given how slowly the pH increases via aerating.

A few questions:

• Should I do an OCLT tonight before I do anything else?
• If the OCLT comes back negative, is a SLAM even necessary or should I just get my FC up to maintain level?
• @tim5055 mentioned getting my CYA to 50 because I live in Phoenix.
  • How critical is that?
  • If raising my CYA to 50 is critical, should I do it after a SLAM to use less bleach during the process?

That's all I can think of for now.

==========================================
Build Type: Plaster
Volume: 10000 gallons
------------------------------------------
Latest Test Result Summary
FC: 3.0
CC: 0.0
pH: 7.5
TA: 150
CH: 350
CYA: 40
TEMP: 76°
CSI: 0.17
==========================================

 

[tim5055]

TA is the last number we ever worry about. If you test your fill watere I bet it has high TA, so you will never win that battle.

FC - 3 is the minimum for CYA 40, so lets bring that up a little. You should target 5 - 7 so it never goes below 3

If you want to keep CYA at 40 and see how it goes as you get into summer, that's fine. No emergency there. Plus, if you have to SLAM 40 is better than 50 for that.

Yes, lets do the OCLT tonight and see where we are. How does the water look??

 

[Oly]

Raise your FC to the top of your target range. Do an OCLT tonight. Don't sweat the TA simply push the pH down when it gets above 7.9 for several weeks and it will fall to a stable level.

 

[iammikeb]

FC - 3 is the minimum for CYA 40, so lets bring that up a little. You should target 5 - 7 so it never goes below 3

Sun is out now. Should I wait until tonight to bring that up - prior to getting my control number for the OCLT - or just do it now?

Yes, lets do the OCLT tonight and see where we are.

Will do!

How does the water look??

I have had it clearer, but it's far from cloudy.

 

[iammikeb]

This is how my boys interpreted, "Hey, you want to help me out?" last night:

 

[tim5055]

Looks nice.

Bring the FC up to around 7 now. Test again just before sunset and we will get of an idea of your UV sun loss, plus loss from organics maybe. Use Pool Math to calculate how much you need to add to get to a nice number, lets say 10 and add that much chlorine. Let that circulate in and test right after the sun is off the pool. That will be your starting number and it will let up see how close your 10K size number is. I like to compare chemical additions that were calculated in Pool Math to what actually happens in the water to narrow down the true pool volume. With my pool I was told it was 25k, but chemical additions monitored over a year long period told me it was really about 23k.

Tomorrow before the sun is on the pool you will test FC/CC again and we will see if you need to SLAM.

It's a nice looking pool. I can see sitting on the steps with a glass of wine.

 

[tim5055]

I forgot to say, for these chlorine tests make sure you are using 25 mL sample for 0.2 ppm accuracy.

Once the SLAM is over (if you need it) you can go ahead and use 10 mL sample for 0.5 ppm accuracy. It will save you reagents for normal maintenance testing and is close enough for us.

 

[iammikeb]

I forgot to say, for these chlorine tests make sure you are using 25 mL sample for 0.2 ppm accuracy.

How does this impact the amount of regents I use? Do I just multiply everything by 2.5?

 

[tim5055]

How does this impact the amount of regents I use? Do I just multiply everything by 2.5?

Each drop in the FC test will be .2 rather than .5

 

[iammikeb]

Each drop in the FC test will be .2 rather than .5

Oh, I see! I still just use "one heaping scoop" of the R-0870 as the TF-100 instructs, correct?

 

[tim5055]

Oh, I see! I still just use "one heaping scoop" of the R-0870 as the TF-100 instructs, correct?

Correct. That is the thing we like about the FAS/DPD chlorine test. You can get very accurate when you need to determine whats going on and then you can save reagents when you just need "close enough" when maintianing the water.

 

[iammikeb]

Okay, I did a 25 mL sample and my FC is at 4. Should I raise it and test again for a control, or just go with that and see where I am at in the morning?

 

[mknauss]

Go with that and test in the morning.

 

[iammikeb]

My morning 25 mL FC resulted in 3.2. Looks like I have some funk growing. Time to SLAM.

 

[mknauss]

Technically less than 1 ppm FC loss, but a quick run to SLAM level FC will not hurt.