Help with algae

[Roddapool]

Here are my numbers

25000 gal vinyl pool

Hayward DE3620 Pro Grid D.E. filter W/1 1/2 hp Hayward super pump

Ph=7.2

TC= 5
> This test was more orange in color then yellow
BR=10


TA= 190 PPM

CH Water stayed clear

CYA= 110 PPM or more no reading on tube when black dot disapeared


One of the things I learned late in my fight was to vacume to waste and clean the filter elem often.
Noticed the filter not working well the presure would go up to around 28 and I was not getting enough water presure comming out of the jets so I cleaned the filter element it was redish in color almost like a rust color.
I soaked it all day in Oxy Clean and rinced it throughly did not seam to make a dent in the color. Put filter back together and ran it all night then took my water test this morning.
Water is clear but I still have discoloring on liner.

Thank you for your help.

[CarlD]

OK:
The two critical numbers here are your FC is >5 and your CYA is > 110.

You have two choices of approach:
First drain 1/2 to 3/4 of your pool and refill to dilute CYA down to easier-to-manage levels (you've been using pucks for a couple of years, right? That explains the high CYA and low pH). You'll then fight the algae with a lower CYA and be able to raise Free Chlorine to 15ppm to kill it.

Your pH is low, but at 7.2 in an algae fight it's FINE.

Second approach: Run a high CYA pool. To clear your pool you will need to get your Free Chlorine up to 25ppm and keep it there until the algae is dead, then, when your water is clear, always keep your Free Chlorine between 8 and 15ppm.

Tough to measure with a kit that goes to 5ppm (the 10br reading is meaningless--it's the scale you use if you sanitize with bromine rather than chlorine.).

If you dilute your pool water with steam distilled water (from any chain discount drug store) you can extend the range of your test kit. I like the CarlD Shot Glass Method: One shot of pool water to one shot of distilled. This will extend your range to 10ppm (it will say 5ppm,but you double it). Or, you can use 1 shot of pool water to 2 shots of distilled. Now the range is tripled and if it reads 5ppm, it's really 15ppm. You need to use 1 shot of pool to 4 shots of distilled to reach 25ppm, but by that time it's VERY hard to get a meaningful reading.

A pool store can test it for you, but they will sell you clarifiers, flocculants and "shock"--basically either di-chlor powder that makes your CYA situation even worse, or Cal-hypo, which adds calcium. If your CH reading is zero, Cal-Hypo is ok, but we recommend simple laundry bleach as having the fastest action and fewest side effects.

It's best to get a FAS-DPD test kit to test for high ranges of chlorine

Go to the pool water problems topic and read the stickied threads at the top of the topic area.

You will need lots of bleach, a good test kit, and lots of patience and persistence.

[Roddapool]

WOW thank you for getting back to me so fast, and thank you for all the info.

I'll keep you informed