What is this in my skimmer?

wpbucher · May 5, 2016

Opened to somewhat green pool this past Saturday (4/30/16). Brushed and backwashed after removing two dead rodents (one had been in there a while) and leaves. Water temp around 50. Filter was clearing pool.

PH=7.0
FC=0
TA=40
CH=110
CYA=10

Added 16 oz of Kem Tek 60% Algaecide

Monday morning, I figured the pool was clear enough to work on the chemistry.

Ended up adding 27 pounds of baking soda to get TA=110 (this was done Monday thru Wednesday in approx 6 pound increments)
PH now 7.2

Once TA=110...I added 98 oz of borax to raise PH.
PH=7.4.
Borates = 30

Added 7 boxes of 20 mule borax and 2 gallons MA.
Borates = 50

PH=7.4

Monday night added 16 oz trichlor and 2 gallons of bleach. Took FC=11
Notice slime in skimmer.

Next morning FC=0. That evening, I added 32 oz trichlor and 3 gallons of bleach. Took FC=16. Next morning FC=13.5 Water looking very clear.
So I think I'm almost done. By end of day FC=2.5

I figure chlorine burned off because of low CYA.
Still getting slime in skimmer, but not as much.

Added 6 bags (16 oz each) of Clorox Shock Plus 4-in-1 (58.2% Dichlor) and a gallon of bleach. Takes FC=18. This morning I checked and CYA=30 or maybe a little more and FC=16.5

Water Temp = 57

I'm on the road. My son sent me the picture above at 4 pm today. Not sure what FC is at the moment. I will be home tomorrow afternoon to test and to continue working on this.

Is this still algae? Is this green algae?

Should I be doing anything else other than SLAMing with bleach?

Thanks for your help TFP!!!

YippeeSkippy · May 5, 2016

I'm not sure what it is but I'm pretty confident the cure is bleach!

Catanzaro · May 5, 2016

Wpbucher:

Please run another set of tests. Your CYA may be higher given the shock thrown into the pool. You raised your TA pretty high (unless I am missing something here) and then adding Borax to raise PH will also increase TA. With a high TA, waterfall and spillover spa, you may have constant PH issues. I personally have been working to lower TA for one year and now I am from 120 down to 70-80.

IMHO, the best thing to do now is to run a new set of tests. If the CYA, TA, PH, CH are all within range, the first step is to clear up the pool in where your FC holds steady and you do not loose more than 1 ppm overnight (overnight test). After the test results, we can guide you along. The only essential item you will probably need is either straight unscented 8.25% bleach or liquid shock (12.5%). Maybe a Wet-Vac to suck up whatever is floating in the skimmer (at least for now).

The magical answer is probably bleach, bleach and more bleach. We usually do not recommend adding shock and algaecide's to your swimming pool. Please keep us posted.

wpbucher · May 5, 2016

The slime in the skimmer kind of looks like the algaecide that I added to the pool. It looks very slimy, but it does not feel slimy. In other words, there is no oily residue. I've been scooping out with my hand and "flicking" it into the landscaping. After scooping, my hand does not feel like it has a residue on it.

I was around TA=80 for all of last year, but thought a higher TA might be better for my heater.

Since the PH was low, I figured that I would take advantage of the low PH and up the TA.

As I add MA throughout the season, the TA will drop some. I have to add MA due to the SWCG and the aeration caused by the spill-over spa.

I added the shock to get chlorine and get the CYA up to 30.....based on the assumption that the chlorine got burned off by the sun. How else to explain a small drop in chlorine overnight compared to a huge drop during the day? Unless the sun caused the algae to grow?

I'll update tomorrow with new numbers. Hopefully I will have FC>0 when I get home tomorrow.

Thanks for your help.

pooldv · May 5, 2016

I am going to pick pollen.

wpbucher · May 6, 2016

So back from the road.

I don't think it is pollen. It has been raining here a lot. Our portable spa cover usually shows a nice coating when pollen is bad...but with all the rain...there is no visible pollen on the portable spa cover.

My numbers:

FC=8.5
PH=7.4
TA=110
CH=110
CYA=25 (barely see dot at bottom)
Temperature=56F
borates=50

The slime was different upon return. Much more concentrated and easy to scoop out with my hand. On the shallow skimmer it was like a little island....like a little tar ball...but not same consistency.

Sorry...I should have taken pictures.

I have trichlor pucks in the chlorinator set to max.

Pool water clear. I vacuumed out some worms (raining a lot here) and the rest of the hot tub.

Lots of rain, so plenty of water to backwash. My backwash is set to 70 gpm for 2 minutes and rinse for 1 minute.

I then brushed it. No visible "dust clouds" when I brushed.

Since it lost 9.5ppm FC in 30 hours, I guess I'll shock it with bleach at sundown and run the filter pump overnight.

Loss of 9.5 ppm FC in 30 hours is better than the 10.5 I lost in 8 hours on Wednesday....so things are improving.

Catanzaro · May 7, 2016

I have trichlor pucks in the chlorinator set to max.

This will help you increase your CYA between 30-50 (you can stop at 50 if you want).

Also, you should be up to SLAM Level, which is 12 at all times until your CYA increases to above 40. You will also need to pass the overnight test. Do not add any more chemicals to increase PH or TA at this time. Please see the following:

Pool School - SLAM - Shock Level And Maintain

wpbucher · May 13, 2016

I brought the FC=14 with bleach and turned on the IC40 and each day I had less scum. Now I am scum free. There is no algae problem that an appropriate amount of bleach cannot handle. Thanks TFP!!!