Help - Newbie

[SkiBikeGolf]

I just tested my water with the following results (TF-100 kit)

FC: 5.0
pH: 7.5
TA: 200
CH: 750
CYA: 135

I had light mustard algae on the walls from the tile line down about 12 inches. I brushed it all off.

The water is cloudy, because I have a lot of fine grain particles in the water. I may have over fed my DE filter with DE after my last backwash last week, or my filter membranes have hole in then.

I think I need to drain the pool about 2/3 rd tp my CYA down to 60 and the get my DH down to about 300.

Should I vacuum first, before draining?

I assume I should focus on the water balancing after I refill.

Any and all help is appreciated.

 

[HermanTX]

If your filter grids has holes in it then you would have a powder coming through your returns. Do you think it is the DE that your refer to as particles? If you suspect your filter grid has holes then that needs to be fixed so you have a properly working filter and pump before you start to drain and refill pool then balance chemistry and rid your pool of any remaining algae.

Brush the sides and bottom and vacuum to waste line - this way you are removing water and not putting through your filter.
Then backwash your filter to remove any algae that may have already circulated there (assuming you circulated after you repaired your grids or if you identified another reason for the particles in the water).

If you proceed to drain pool you may want to use a sump pump rather than your pool pump. Continue to brush and vacuum to remove as much algae as possible. Ensure you don't get air in your pool pump if you vacuum to avoid pump damage. Not sure how you are set up to vacuum - most connect to a skimmer line. If you drain below your light you may want to remove it and clean it to remove any hidden algae.

Once you reach your maximum drain target - I would dump a gallon of liquid chlorine to kill remaining algae. If you drain 2/3 then you have about 5000gals remaining. If using 10% liq CL that would raise your FC to 20 (according to Pool Math). Others may have other ideas. Then start to refill.
Have you tested your Fill Water? You have both high TA and high CH. Draining your pool will also help reduce CH. Verify what your fill water is so you can prepare how to balance your chemistry. You don't indicate if you have a SWG or if you just use liquid chlorine to sanitize the pool. Have some MA on hand if your fill water has high TA.

I am sure others will chime in on ideas but this will give you some points to consider and prepare.

 

[SkiBikeGolf]

<< Brush the sides and bottom and vacuum to waste line - this way you are removing water and not putting through your filter. >>

I'm not quite sure how to do this.

<< If your filter grids has holes in it then you would have a powder coming through your returns. >>

I don't see any powder coming through the returns, so I suspect the particles are some sort of calcium.

I did test my fill water:

FC: 0
pH: 8.1
TA: 170
CH: 175
CYA: 0

So here is my plan:
1. I brushed yesterday
2. Vacuum
3. Backwash
4. Lower water
5. Not sure here: Should I add liquid chlorine to start of with some FC?
5a. Open filter to clean and inspec filter grids
6. Refill
6a. Prime pump and add DE to filter
7. Test
8. Lower ph and TA with MA
9. Aerate to raise pH without affecting TA
10. Add MA to lower pH and TA and repeats 8-10 as needed to get pH and TA in range.
11. Do I need to SLAM here or just add liquid bleach as need to get FC in the appropriate range.

Question: why does my Pool Math app say the ideal FC range is 1-3 while the Chlorine / CYA Chart indicate 8-10 as target FC with CYA @ 70?

 

[SkiBikeGolf]

Armed with accurate chemistry values, I draining my pool to get the CYA under control. At first, I thought I would have to drain 2/3 of the pool, but it appears I can drain 1/2 way and end up with a CYA value of 67.

Any thoughts?

 

[duraleigh]

What does your pool water currently look like? Got a pic? More to follow but a pic would be quite helpful.

 

[SkiBikeGolf]

As you can see, I am about 1/2 way drained for my refill

 

[duraleigh]

Well, that water looks pretty nice so I think the first order of business is to get your CYA in control (and reduce CH at the same time) with a partial drain........just as you are planning.

I would suggest you drain about 50-60% and then test CYA again.....keeping your FC up around 5.0 the whole time. That retest of CYA will tell you if you need to reduce further so let's see what the test results are. This is just an eyeball observation but you do not appear half-way. You know that better than us so you be the judge.....don't skimp.

 

[HermanTX]

I would suggest you drain about 50-60% and then test CYA again.....keeping your FC up around 5.0 the whole time. That retest of CYA will tell you if you need to reduce further so let's see what the test results are.

If there has not been any new water added, wouldn't the remaining water in the pool still be the same CYA as before the draining began? Isn't the CYA in the existing water lowered by dilution and dilution has not started yet.
Can you clarify?

 

[HermanTX]

@SkiBikeGolf - ensure your filter is ready once you begin to fill after you stop draining.
Also, it would not hurt to increase your FC level to kill any remaining algae.
As you fill (maybe at 1/2 way back to normal level) you should test and add Chlorine to keep it in good range.

Question: why does my Pool Math app say the ideal FC range is 1-3 while the Chlorine / CYA Chart indicate 8-10 as target FC with CYA @ 70?

Your Pool Math ideal and target ranges read what is your CYA and gives you the minimum target level. This is based on your latest test data. Could you have put in a lower CYA ie. from your fill water test or mistyped? Look at it again after you input new test results during your refill. Keep us informed and as a reminder - turn on the feature to link your pool math logs to your ID. Thanks.

 

[SkiBikeGolf]

Well Dang!. The actual CYA after draining 1/2 way (about 8,000 gallons) and then refilling ended up at 90-100

I was surprised the FC dropped so much and I did not expect the pH to go up. The TA ended up close to predicted and the CH actually was better than predicted.

I just added 1/2 gallon of 32% MA to get the pH down to 7.5

I am about to go out to add 1 gallon of 10% bleach to raise the FC. Pool Math predicts it will be 6.2 when done.

I did completely take apart the DE Filter and clean.

I also shared my Pool Math testing.

The one mistake I made was not keeping the FC high during the refill.

I think I should SLAM? Any advice is appreciated.

 

[duraleigh]

Are you going to leave your CYA at 90? Do you have an SWG?

 

[SkiBikeGolf]

I do not plan to drain and refill for a while I do NOT have a SWG.

Am I reading the CYA/FC chart correctly?

The chart says my FC target level is 10 -12.

However, when I read about FC above 10, many posts on the internet say it is not safe. Will my swimmers complain with FC above 10?

 

[mknauss]

Will my swimmers complain with FC above 10?

No. They will not even notice it. At a CYA of 90, there is a fraction of the active chlorine present at a FC of 10 ppm than there is at a FC of 1ppm and 0 CYA.