Pre SLAM Help - TFT Results - Pool Math Ignorant

[Geojaneo]

Just tested (first time) with TFT-100 Kit as I need to SLAM pool

Results:

FAS/DPD 2.0
CC .5
CYA
R-001 <20 - 30 ppm
CYA
R-7065 ??? 40 could still vaguely see black dot

TC 2.5

PH 7.2


I went to the Clorine/CYA Chart for SWG. Since my CYA is < 20 - 30 ppm, I have no idea how to calculate the correct shock FC. Once I have that number, how do I get the calculation for how much bleach/liquid chlorine to add and how often. I also tried to use the pool math calculator, but I'm beyond lost!

Not only am I a pool newbie, but a mathematical moron as well! As long as I'm asking so many questions, I could only get 2 gal of liquid chlorine and more won't be available till next week. Can I also use bleach or should I just use bleach?

Much thanx and sorry for all the "duh" questions!

 

[pooldv]

We don't recommend SLAMing below 30 CYA. So, raise the CYA to 30 first. But, the shock level from 0 to 20 is the same.

Here is the process to SLAM Process

Here are the instructions for pool math, Pool School - PoolMath

 

[MikeInNH]

How does the pool look? If you maintain the minimum FC (plus it holds over night) and CC's are .5 or under then you are good. Your FC is low though. If the pool looks bad then continue below.

I would assume the CYA on the high side which means you need a shock FC of 12 for 30ppm or 16 for 40ppm of CYA per the chart. I'm not sure which one you are at for real. Two links below, one is the SLAM link and the other is the pool calculator. You need to look at the top 2 sections, tannish and yellow. Put the pool size in, your sig says 21100 gallons, then put the FC numbers in. You list it is at 2 now and you need to target 12 (or 16). Then select the bleach level, 8% is common. I see you as needing 323 ounces of bleach to get the target of 12 for SLAM. You can use cheap Walmart bleach just go for the highest concentration with no added stuff like perfume. After hitting that SLAM number you need to monitor it often to keep it up there until you meet the OCLT goal.

http://www.troublefreepool.com/calc.html
Pool School - SLAM - Shock Level And Maintain
Pool School - Perform the Overnight FC Loss Test (OCLT)

I seem to type to slow.

 

[Geojaneo]

My previous threads under Chem 201 described as treatment (aborted) cuz of staining and slight pinkish "algae" SLAM was recommended. While waiting for new test kit, we've added some liquid chlorine for a few days and pool looks better - no pink tinge but slightly cloudy. So I should increase CYA and retest b4 contemplating SLAM?

 

[pooldv]

Below is an excerpt from the SLAM process located here, SLAM Process

SLAMing an outdoor pool is most effective when CYA is around 30 to 40. Below 30 you lose too much chlorine to sunlight. As CYA goes up, SLAMing requires more and more chlorine, which starts to get impractical around 80 or 90. With CYA above 90 we recommend replacing water to get CYA down before you start the SLAM process.

 

[MikeInNH]

In forums it's best to keep the issue you're dealing with in one thread instead of creating a new one. It helps to have the back story. Putting a cover on the pool also helps with chlorine loss due to sun.

 

[Geojaneo]

Thanks Mike! Makes good sense! About to start raising CYA as we just got it. Your numbers gives me something to double check against. Much appreciate you taking that extra step - have a lobsta me!!! So glad I found TFP - can't wait to have one! Thanks Pooldv for your guidance!!!

 

[Geojaneo]

I now have the My Salt Pool CYA to raise my levels. Today's readings are:

FAS/PDP 1
CYA < 20 - 30
PH 7.2
CC .5
Clorine Drop TC 2

Using the pool calculator, and entering 10 for the CYA (since I don't know the exact reading) it calculates adding 56 oz (by weight) of CYA to bring level to 30 (as suggested before I SLAM).

Since our TC level has dropped in the past week, should I continue to add liquid chlorine to be able to swim during the week while waiting for the CYA level reading? My Salt Pool CYA says to balance water before adding.

Much thanx!

 

[MarianParoo]

Yes, add chlorine! And if put the CYA in a sock and you are aggressive about squeezing the sock, it will dissolve faster. You should be able to retest your CYA within 48 hours.

 

[Geojaneo]

Appreciate the help! My Salt Pool CYA Pool says preferred method is to add to skimmer - assume that's a slower process? Also says circulate water for 24 hours - does that mean recirculate WITHOUT filter on?

 

[pooldv]

The CYA will be trapped in the filter and will take a week or so to dissolve. If you backwash the filter the CYA will be washed away. Here is how TFP recommends adding chems, Pool School - Recommended Pool Chemicals

It is important to maintain FC above minimum for your CYA, [FC/CYA][/FC/CYA], to keep the pool sanitized and safe to swim in.

 

[Geojaneo]

STANDING BY TO SLAM Re: Pre SLAM Help - TFT Results - Pool Math Ignorant

I have raised my CYA to 40 and can now SLAM. The FC/CYA Chart indicates at 60 (not recommended) to shock it needs FC 24. BUT ... on the bottom of the pool math calculator - it indicates 16 for shock for SWG

Here are my current test results

FC 6
CC .5
TC 6.5
CYA 40
PH 7.2

I did the OCLT test last night and this a.m. and lost 2 ppm of FC (last nite - FC 8.0, CC .5)

I have read and reread the SLAM instructions but am confused with the CYA numbers for SLAM. On the Pool Math Calculator, I selected the goal levels set by TFP.

If 16 is the correct SLAM level, then I add the correct amount of chlorine at once, retest after one hour and then add chlorine again until I get to the 16 ppm again and then OCLT tonight (.30 after adding last chemical and then test in a.m. and if no loss greater than 1 ppm - I'm done, correct? Also to clarify I'm to turn off the SWG while slamming?

 

[Mr Bruce]

SLAM at 40 CYA. After the SLAM bring it up to 70-90 for your SWG. Yes, SWG off for the duration of the SLAM.

For a SLAM, you test the water several times a day, and add bleach as necessary to keep it at 16 FC. There is no need to do an OCLT until the water is clear and CCs are low/0.

 

[Geojaneo]

Thank you Mr. Bruce! Will forgo the swim (sadly) and start the SLAM now! The water is currently pretty clear but some green algae is on our ladder.

What forum would be appropriate to suggest the inclusion of turning off the SWG on the SLAM instructions - it's not there and I just happened to read a thread and picked up on it!

 

[MarianParoo]

Some people DO leave their SWG's on during a slam, so that's why it's not there. It's kind of a personal decision. It MUST be off for the OCLT.