SLAM in progress...

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D

derickx

0
Jul 30, 2018
17
KCMO
First, thanks to the community here, I have read quite a bit about the philosophy here and appreciate the scientific approach to the "art" of pool care.

I have owned my pool for 20 years. This year has not been a good one.

I believe that I am dealing with a mustard algae outbreak. The last couple of years I have mostly just used test strips and the Clorox pucks from Costco, and it was fine. But this year I started having algae even with high chlorine levels, and after ordering a real CYA test (the strip said 30-60, so I thought it was fine) I discovered my CYA was closer to 240 (!)

Okay, so a couple of partial water dumps, and my CYA came down to 45-50. So I started the SLAM. I have backwashed heavily, which has lowered my CYA a bit more. It has been nearly a week, I've aded DE to my sand filter multiple times, and my water is still cloudy and not just white but slightly greenish. For the first time, I am mostly using liquid chlorine.

Today's Readings:

FC 25
PH 7.2
CC 0
TA 90
CYA 40

My plan is to keep brushing and vacuuming until it finally clears, From the CYA/Chlorine chart, I was targeting 29 for FC, but since the CYA seems to have dropped I assume that I should adjust my target to 25, which is where I am now.

Is there anything obvious that I should be doing differently?
 
Follow the SLAM Process procedure using the normal shock level FC as shown in [FC/CYA][/FC/CYA] until you pass the three criteria for a successful SLAM. Once that is complete, you then raise your FC to Mustard Algae shock level for 24 hours. Then maintain your FC at Mustard Algae maintenance levels.

Pool School - Mustard Algae

- - - Updated - - -

Can you put what name/model test kit you are using in your signature?
 
Thanks for your reply.

Hmm, I didn't realize that there were specific "mustard algae" instructions. So, I will let the FC drift down to 16 or so.

I have a Taylor 1004 I purchased earlier this year, but have purchased the CYA Dot test and DPD-FAS tests separately from TFTESTKITS. I figured that would get me though this year.
And for these high Chlorine levels, I'm only using a 5 ml DPD-FAS sample, since I don't really care about the fractional values of FC.
 
Well, I just brushed the pool, but tomorrow there should be some precipitate on the steps that I can take a shot of. I don't know with certainty that it is mustard algae, but it sure is persistent whatever it is. I do recall that 15 or so years ago (when my wife was in charge of the pool) we had what we believed was a mustard algae event. Looking back through her logs, (she keeps much better records than me) I see that the pool store testing sheets from 2005 say that 30-200 ppm CYA is the acceptable range. Hmmm.

I was not successful in obtaining a sample of this "mustard algae" a couple of weeks ago when I started the drain/refill process, when there was quite a lot of it. I have since decided that the proper tool to collect a sample is a turkey baster.
 

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2008GMCsierrasle said:
Out of curiosity, why do you believe that it is mustard algae? Do you have any pictures? Been trying to see some REAL mustard algae pics from members instead of the hundreds of different MA pics on the www.
Click to expand...

SLAM status: Free Chlorine has reduced from 21 to 19 overnight. CC = 0, PH 7.2. I'm using a 5 ml FC sample, so that may not be totally accurate but it's close, and the overnight chlorine loss test is close to being fulfilled. The pool is clearing but I still can't see the bottom of the 8 foot deep end.

Here is a photo of what I fear is mustard algae. I don't actually see it growing anywhere and my pool is at a 45 degree angle to the sun so all parts of the pool get sunlight on a sunny day. This stuff falls out of suspension and I keep brushing/vacuuming it up. I've read that mustard algae looks like dirt or sand, the particle size is much smaller than sand, but if this doesn't look like mustard algae then that is a good thing. It doesn't really seem to react when pouring 10% bleach on it, so maybe this isn't mustard algae. That is what I hope.
 

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mknauss said:
Complete the SLAM until all three criteria are met.
Click to expand...

Hi and thanks for weighing in.

Okay, so the three criteria are:

CC-0: check.
Overnight Chlorine loss: 0-1PPM: close but no cigar
Clear Water

Forgive my question, but if the OCLT is good, then isn't the cloudyness simply a matter of filtering?

Oh, and the POOL MATH says that in my 20K pool, a 40 lb pail of trichlor pucks will add 136 ppm to my CYA total.
Yikes! Owned a pool for 20 years and I had no idea.
 
You would think that you only need to filter - but - it has been found that maintaining shock level FC until you get the clear water is essential.

One, it takes little extra chlorine to maintain the shock level FC by that time. And many times stray algae may be found in a ladder, light niche, etc .

It is your pool and if you wish to skip the clear water requirement, do it. We just do not recommend it.
 

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Yeah, just dead algae....no mustard. Now to get your pool clear, make sure you are filtering and cleaning and brushing to the max possible.

Are you backwashing your sand filter?

Are you running pump 24/7?

Are you brushing all the debris up into the pool water so the filter can catch it?

Review the SLAM procedure, especially the part about all the above and I think you will see your pool turn crystal clear day by day.

At this point, many are afraid to brush the debris off the pool floor because it clouds up an otherwise clear pool......that's a fatal mistake. Keep you pool water moving and keep ALL the debris off the pool floor and into suspension so your filter can work.
 
duraleigh said:
Yeah, just dead algae....no mustard. Now to get your pool clear, make sure you are filtering and cleaning and brushing to the max possible.
Click to expand...

>Are you backwashing your sand filter?

Yes, at least once a day. I am also adding Diatomaceous Earth during the day when I can watch the pressure.

>Are you running pump 24/7?

Yes.

>Are you brushing all the debris up into the pool water so the filter can catch it?

Yes, except what I left on the steps for two days to acquire enough specimen for my mustard algae test.

>Review the SLAM procedure, especially the part about all the above and I think you will see your pool turn crystal clear day by day.

This is exactly what I am doing, and seeing.

At this point, many are afraid to brush the debris off the pool floor because it clouds up an otherwise clear pool......that's a fatal mistake. Keep you pool water moving and keep ALL the debris off the pool floor and into suspension so your filter can work.
Click to expand...

Yes I understand this, and it is what I am doing. I certainly understand that debris sitting on a pool floor will never be cleared from the pool unless it is moved.

Thank you for your attention.
 
Your pool is very close to being clean and you may not need to backwash so frequently now. I would suggest backwashing only when the pressure rises 25% from normal.....you may be able to go much longer between backwashes at this stage.

Anyway, you have a good grasp of the process and are headed soon for a crystal clear pool.
 
Here has been my filter management theory for this process...

As the water has been clearing, less and less matter gets caught by the filter. The pressure on "clean" sand is 15 lbs. When the pressure gets to 22 or 23 lbs then the pump system is moving notably less water, and my ancient Hayward Super Pump lid is no longer being constantly splashed underneath by the water from the skimmer. This has been my traditional signal to backwash. Now, this is a 50% pressure rise rather than 25%, but it is what I have followed for 20 years. I assume that the Crystal-Flow Sand filter is as old as the pool is, 40 years. I have replaced all the internal parts as they failed, and I don't believe anything except the external tank and stand are still original.

I have a box of DE from several years ago, and decided to use it in the attempt to speed up the filtering process. Early in this process I was adding too much DE and had to backwash too often, and it seemed to me that the backwash water wasn't dirty enough to justify a backwash even though the pressure was high. So, I've cut back the Diatomaceous Earth to maybe a cup and never add any when the pump will be running overnight.

Anyway, that is maybe too many details about what I am doing, but my SLAM will almost certainly be concluded in the next couple of days, I do appreciate the advice and encouragement.
 
You certainly have mastered all the concepts involved. Mas985 is the pump and hydraulics expert on the forum and the 25% increase is what he came up with as the most efficient way to use the energy expended through the pump. 50% increase works just fine.

There is often advice given (not on this forum) to allow a 10 psi pressure rise but some well designed systems have a clean psi of 10, so to go all the way to 20 (100%) just doesn't work well.
 
Yes, "Backwash when pressure rises 10 lbs" is the advice I received from the previous owner of this pool and several other places. But, to me, it seemed that water flow gets notably impaired at 7-8 lbs in this system and so that is when I do it, paying more attention to flow than to pressure. It just seems easier on the system to have freer flow, and presumably would use less electricity.

That is interesting where the 25% pressure rise theory came from, I had never heard of that before reading this forum.

I have a clamp AC current meter, I will take some amperage readings at different pressures and see if they back up Mas985's efficiency thesis.

I am still losing 2ppm Chlorine overnight, and still brushing and vacuuming some precipitate. But, my pool at least looks like a pool again.
 
Okay a progress report. I am still losing 2ppm FC overnight and vacuuming up some precipitate (dead algae I assume,) every morning. So, I need more chlorine.

There's a Leslie's pool store less than 4 miles away and a Lowes maybe 2 miles. Here, Leslie's charges exactly 25% more for their gallon of 12.5% Chlorine as Lowes does for 1 Gallon of Pool Essentials 10%. Advantage here goes to Leslie's because A- it's stored properly, B-you get a cardboard box of 4, C-It takes up less space for the same Chlorine, and D- They always have it. You can check Lowe's inventory of this stuff online, and it's out of stock more than it's in, and when it's in it might be 2 bottles and might be 4.

So, since I was going to Leslie's anyway, I took some water to test, just to compare with my own testing.

FC Leslie's- 7 Me- 8.5
CC Leslies- 0.2 Me- 0
CYA Leslies- 80 Me- 45
TA Leslies- 90 Me- 80
ph Leslies-7.6 Me- 7.5

The real interesting thing that they "recommended" was 8 quarts of PhosFree since my phosphates are 2500 (!)

I bought my Chlorine and checked their prices for PHOSFree online, in 2liter bottles that comes to $144.00. PLUS TAX!

Man, there goes my beer money. Theoretically.
 
You do not need to concern yourself with phosphates. And the last product you would want to use anyway is PhosFree. It is not a quality product to reduce phosphates.
 

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