Got my kit, help interpret my first test!

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Partial Draining now. Almost completed (~60-70% drain). Once the water level dropped below the top step, I took a Trichlor tablet to one of the areas of suspected black algae and it immediately removed the black spot. This should be confirmation that it is indeed black algae?

I plan to purchase a metal wire brush recommended for black algae removal and begin scrubbing furiously daily, starting now and through the SLAM i hope to begin in the next day or two, after I re-fill and take a new set of readings.

Am I on the right track?
 
Update: Partial drain has completed and I have begun refilling through garden hose for the last 5 hours or so. I purchased the metal wire brush and have been hitting a few of the black algae areas pretty hard- some of the smaller spots have already been removed with just a few minutes of brushing.

Few questions:
- Do I need to be adding bleach at this point with all the new water going into the pool? Or, wait until its full?
- Does the filter need to be running prior to it getting full? If so, not sure how I can go about adding any DE to the skimmer in the next few hours considering I have a long ways to go before the water level hits that point. Is it okay for the filter not to run until getting the water line back up to this point?

Just want to make sure I don't give algae and bacteria a chance to go haywire while I don't have much Chlorine in the pool and/or the filter isn't running. But, I would like to wait before adding anything until the water level gets back up so my new water readings will be accurate.

Thanks
 
Thanks for the advice! Didn't think of that...

So here is my plan:
1- Get waterline to full overnight tonight
2- Add DE to the skimmer following the backwash/drain and start the pump in the AM.
3- Test water sample to get baseline measurements, and adjust pH as necessary BEFORE the SLAM process. (Is this correct, or can I balance it later??)
4- Use Pool Math to determine the necessary FC shock amount for my CYA level.
5- Begin SLAM process tomorrow evening after getting home from work once the sun goes down, and ensure checking FC levels at least twice daily.
6- Continue using wire brush to scrub areas of black algae daily, while maintaining my FC levels until I: have CC less than 0.5, pass the OCLT, and have clear water.
7- After SLAM, I will keep my FC levels in between my Target and Shock levels for approximately a week to ensure there is no new algae bloom and that black algae is fading.
8- Let my FC levels slowly come down to Target where I will make adjustments to hold steady, as necessary.

How's my plan sounding?? Hope I am ready for my first SLAM!
 
Update:

Got the pool re-filled. Have been scrubbing black algae spots 1-2x/day with wire brush.

New readings are below:
FC = 4
CC= 0.0-0.5

CYA = 40
pH= 7.8 (this may be skewed, as it was checked after adding bleach this morning to keep the pool with something in it while I was at work before I could do official measurements tonight. Previous pH was 7.6 yesterday).
TA = 150 (seems much higher than I'd like?)
CH = 300

Can't believe what great levels my CYA and CH dropped to after the partial drain.

Just started the SLAM after taking readings. According to pool math, my Shock level is 16, where I will attempt to keep it and perform OCLT for the next few days. The water is already "clear" and my CC is already in the appropriate range, so seems like my decision to stop SLAM will be primarily based on the OCLT results.

Any other words of wisdom? So stoked I got this TF-100 test kit and for all the advice I have gotten here already. I am actually starting to enjoy taking care of this pool. My wife things someone has replaced her husband.
 
Yay!!! Good job!

Sorry no one got back to you about lowering pH before you started slamming. Our miss... But no worries. If FC ever gets around 10 or below, retest the pH and adjust it down to 7.2-7.4 before raising FC back up.

Did you test CYA in full sun? I can't tell if you did it this morning or tonight.

Don't worry about the TA for now.

Happy slamming!
 
Thanks for the reply.

I tested CYA as the sun was setting, so pool had little direct sunlight, though I was standing/reading in the sunlight.

Thanks for the info re TA and pH...

About 1.5 hours ago I added what Pool Math said to get my FC to 16. When I just re-tested my FC is instead now at 26. Given that I am pretty sure my previous measurements are right-on, I am wondering if this discrepancy is due to my incorrect guesstimate of my pool size in gallons. If I work backward on Pool Math and re-calculate a new gallon size, I come up with only 7,500 gallons!! Can this be right? (See pictures of my pool in previous posts). I have previously been estimating 13,500 gallons based on 15ft x 30ft x 4.5ft

Am I just really over-thinking this?
 
No, you are not over-thinking. There is a descrepency somewhere.

Volume is easily the first culprit. With 15x30x4.5, I get 15.1K. Make sure those numbers are the actual water depth, not PB numbers.

Other ideas that could contribute a bit:
Chlorine can be really fresh and will be over-strength when new. Your CYA test can be +/- 10 ppm.

How much chlorine did you add?

No worries. Your higher FC isn't going to do long-term harm!
 
I added 2 jugs of 8.25% bleach (121oz) as that is exactly what was recommended by Pool Math for 13,500 gallons with FC at 4, Shock level of 16. No idea how that overshot so much to get to 26.

Screen Shot 2016-08-25 at 9.01.09 PM.jpg

Just for the heck of it, I just ran a second FC test (about 1-2 hrs since the first) and came up with FC = 26 again.

Something is throwing me for a loop here. One thing I am wondering is if I possibly started with a higher FC than 4 when I originally tested, and therefore miscalculated how much bleach to add. Though I doubt that was the case because I was purposely trying to be extra careful. Who knows
 

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Are you home today? If not, I would let it go until tonight.

When you are home, I would see if you can try to remeasure your water volume and run another CYA test. It can't hurt. I know there are some online calculators for irregular-shaped pools, but I am not familiar with them.
 
I would repeat the CYA test in full sunlight. Your SLAM FC level depends on this result. Back to the sun, vial at waist level, hold with two fingers. Tedious, but important. If the level is between the numbers on the vial, round up to the next higher number. Pool School - CYA

You can let FC drift back down. Your overshooting the FC could be a combination that your pool is slightly smaller and that the bleach is stronger.

Make sure that you don't let the FC sample sit as it will turn pink and it is best to do an oversized scoop of FAS-DPD powder. Don't worry if some powder doesn't mix. Pool School - FAS-DPD Chlorine Test
 
Great, thanks to both of you for the advice.

I will run the CYA test in full sunlight again to determine if I was off previously. Looks like I had been measuring it correctly with the 2 fingers, waist-level, and rounding up. I just wasn't doing it in full light.

I will let FC come down to near 16 but not let it drop past that point until I can get the CYA test completed. I am working today, so may or may not get this done today.

Thank you!
 
Thanks, will do. I plan on re-testing CYA in full sun, and staying on top of my chlorine additions.

As an aside, just got home from dinner and re-checked FC after adding the 100oz of bleach that Pool Math said would get me to "16". Current level is now at 20 (2 hours after addition). So, as we thought, something is definitely off in my calculations. I now need to figure out if its the pool volume, CYA, or something else.
 
MarianParoo said:
We'll be here.

- - - Updated - - -

My bet is that pool volume is the primary culprit, but a check of CYA is a great idea too!!!
Click to expand...
That's where its throwing me for a loop though...

If it is the volume, then according to Pool Math my pool should actually only be 8,000 gallons to account for the FC change I am seeing with these bleach additions! There is just no way that can be the case, as if anything, I feel my estimate of 13,500 gallons is an UNDER-estimate.
 

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