Second Ever Pool Opening, Green Monster This Time Around :(

garybtru

Well-known member
Apr 24, 2017
166
Upstate NY
Hey all,

So I this is my first time closing AND opening in succession... 2 autumns ago I had a pool store close the pool, then in Spring I opened it to see fairly decent/clear water! I closed the pool myself last fall (withOUT polyquat) and this Spring is... a different story!

101850

(Noooooo!)

Last Spring opening, my levels were:

FC=4.5
CC=0
ph=~7.3
TA=60
CH=50
CYA=20

This Spring my levels are:

FC=0
CC=0
ph=7.5
TA=100
CH=25
CYA=0

Soooo it looks like the first thing I need to do is get my filter circulating and bust out the good old stabilizer sock and throw it in the skimmer basket to get my CYA up? Then once my CYA is about 50 or 60 it's time to go down to SLAM town, right?

Another quick question: my sand filter is completely empty... after I get the drain plug back on do I need to backwash FIRST? Or should I run the filter in "filter" mode for a good 10-20 mins or so, to get the filter full of water before doing the backwash? (Or does it not matter either way?) :)

Thanks!
-Gary
 

Msch99

Gold Supporter
Bronze Supporter
Jun 11, 2018
388
Verona, MO
Surprised cya went to zero. I think it would have to be due to either water exchange over winter or possibly turned to ammonia. An expert will probably chime in soon, but I think the first step would be to raise FC to 10ppm, check again in 15 minutes or so. If CL has big drop, probably cya turning to ammonia and I believe you need to clear that out first. If you put cya in with ammonia problem, you just make more ammonia.
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
22,990
Laughlin, NV
I suggest first, before adding CYA, do a quick test. Add enough liquid chlorine to raise your FC to 10 ppm, circulate the pool water for 15 minutes, test your FC. If above 5 ppm, move into your SLAM. If the FC tests at 5 or below, again add enough liquid chlorine to get our FC to 10 ppm, circulate for 15 minutes, and test FC. Continue with that until your FC holds at above 5 ppm.

Then add 20 ppm CYA (I assume the water had CYA in it when you closed it) via the sock method. Once that dissolves test your CYA after 24 hours. Start your SLAM at 12 ppm FC immediately when you add the CYA.

Do lower your pH to 7.2 prior to starting the SLAM.
 

Msch99

Gold Supporter
Bronze Supporter
Jun 11, 2018
388
Verona, MO
Not sure proper procedure for sand filter, I just hooked it up and opened vents and let it back fill with water, then ran it.
 

garybtru

Well-known member
Apr 24, 2017
166
Upstate NY
Thanks guys! I can't remember what I had the CYA at when I closed, but I think it was pretty low (for me) likely around 40. I drained the water to about 8" below the return jets, so maybe thats why I lost the CYA, we've had a lot of rain the past month or more, so it's been gettin a lot of new water into it.

The previous year closing had the CYA around 70-80 I believe. Maybe that helped hold in the chlorine longer, hmph.

Should I lower my pH before adding stabilizer?

Thanks again!
 

garybtru

Well-known member
Apr 24, 2017
166
Upstate NY
Weird, does adding CYA increase the pH? I only had about 0.25 lbs of slow-n-lo left, which I figured wouldn't do much... but I added that at like 6:30, then put the CYA sock in around 6:45 and I just checked my pH at like 8:15 and it's 8.2+! Do I have to wait for all of the CYA to dissolve completely before checking the pH again?

Thx!
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
22,990
Laughlin, NV
CYA slightly lowers pH.
Nope, adjust your pH now.

Try to not use dry acid very much. The sulfates build up in your pool water and can corrode metals, concrete, etc.
 
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