mustard algae in new england?

May 23, 2013
29
ok, so i'm new to this forum and this has been a "must read" and very enlightening for me. Here is my situation and members please guide me and let me know if you agree...

Last season battled yellow/green algae almost all season. My solution (dumb) was to add pool store chemicals and vacuum every other day. Bad, I know now! Fast forward to last week when I opened it and removed the cover. Green swamp. added 10 lbs dichlor based bagged shock, and put 3 hockey puck (trichlor) tabs in the auto chlorinator. vacuumed to waste and swept all algae to a clean looking pool. However, sand and silt like algae (mustard algae?) kept reappearing in the same place...shady side bottom of pool. kept adding 5lbs shock and vacuuming and mustard algae kept returning in 24 hours. Meanwhile, I am never able to get a good FC reading at the pool store and using my test strips above .5ppm. I have since ordered the 2006 test kit and await delivery! I suspect the algae is stealing all my shock and chlorine.

To confuse matters more, my CYA seems to be all over the map, from 189, to 42, to 106, to 62.....in 4 pool store water tests done in the last 9 days. I have drained about 20% of the pool and replaced the water. I also stopped the dichlor shock and temporarily replaced with cal-hypo....no better results :(

So, now I believe my best option is to treat for mustard alage. Agreed? Reading the forum instrux, I need to get to my shock level as dictated by my CYA level. How long do I keep it at shock level since I'll always fail the OCLT b/c of the mustard algae? At what point do I bring the pool to mustard algae shock level?

Some other pertinent details. I will now be shocking with 12% liquid bleach/shock and chlorinating with 8% bleach and converting to the BBB method. Aside from a couple of beach towel sized areas of what I believe is mustard algae, the pool is crystal clear.
sand and silt like algae brushes away easy but keeps reappearing in the same spot. Even after vacuuming to waste.
Most recent water test results from the pool store yesterday:
FC .14
TC 1.09
CC .95
PH 7.7
ALK 101
CH 296
CYA 62
water temp is 66

SUGGESTIONS AND HELP APPRECIATED!
 
Welcome to the forum. :lol:

That you have NO CHLORINE in your pool jumps out. That you CC's are greater than .5ppm also jumps out.

You need to shock your pool. read "How to Shock Your Pool" up in Pool School and follow those directions explicitly.

Your test results look like a pool store digital readout (no good) or a LaMotte ColorQ (often not so good, either)

If you really want to manage your pool water, you will need a drops based kit to give you the information you need.

Whether you have mustard algae or not, bring the pool to shock value as soon as you can and then HOLD IT THERE until your pool is crystal clear and the algae is gone.
 
Welcome to the forum :wave:

I have since ordered the 2006 test kit and await delivery!
Good! When will you receive it?

I suspect the algae is stealing all my shock and chlorine.
Yep, that and any sun that hits the pool :wink:

Looks like you have kinda settled on CYA of 60ish. Shock level for that would be between 18 and 24 FC. So, starting with zero FC, it will take about 4 gallons of 12% just to reach shock level.

Have you found the Pool Calculator yet? Link in my sig.
 
I should receive my drop based test kit by the end of the week.

A couple of additional questions while bringing the pool to shock level...

1. do I brush and/or vacuum the algae to waste before shocking? Do I continue to brush/vacuum to waste during the whole shock level process? How would I tell if its gone if I keep brushing it and vacuuming?

2. kinda hard to tell if i'm maintaining shock level since I am awaiting my k-2006 test kit and my test strips only measure to 10ppm? Also, how long after shocking do I re-test FC. Any tips on doing this while I await k-2006?

Thank you!
 
30 minutes to an hour after adding chlorine you can test. With strips there really isn't anyway to tell if you are - you could use 1 part pool water to 1 part distilled but it loses accuracy and strips aren't accurate anyway.

True Mustard Algae disappears while at shock level, only to reappear when FC drops to normal. I believe what you are seeing is the remnants of a "nascent" algae, meaning you are on the verge of a full green bloom but you stay only 1 step ahead of it, the chlorine is being consumed as it is added and the dead algae drops to the floor in the form of the particles you are seeing. You can continue to vacuum to waste while shocking. I would attempt to hold 24 for several days vacuuming to waste and see if it returns. If it returns at shock level its probably just dust or pollen. In your case based on your description and the test results (however unreliable) leads me to think dead algae.
 
Last couple questions before I begin my journey to get to shock level!

Should I begin shocking during the day, or wait until dusk?

Any guess as to how often I'll have to keep adding shock to keep the shock level? every 3 hours, every 6? every hour? Seems like potentially a boat load of 12% liquid shock?

again, I only have the strips to test until I get my new k-2006 kit at weeks end. You recommend that I wait until then to begin since according to the chart my shock level is 24 and my strips only test to 10ppm?

Thanks!
 
Ya, I'd wait.
As for how often, a hypothetical. I suggest starting late afternoon on a Friday. Start adding and testing hourly. If after an hour you don't detect a FC level higher than 1, test and add every 30 minutes until you reach shock level. I had a pool over the weekend (Sunday) that took additions every 30 minutes over the course of 3 hours before shock level started to hold. By starting late in the day, sunlight won't be a factor as much. Then continue to hit it hard the next day, evening and so on. I started a pool Sunday at noon and today I could almost see the bottom, and it had ammonia! You should get at least 4-6 cases of shock. Even if you don't need it all to clear the pool you will use it for daily chlorination.
 
thanks poolmom. How do you maintain shock level during the very late overnight hours? Just wait until first thing in the am and get it back to shock level if it falls below? My pool is crystal clear and has been....aside from patches of what I believe is mustard algae that come back every day.

Is the trick the idea that "eventually" the pool will hold the shock level for an extended period? and the algae doesn't reappear for lets say 48 hours? then i'm free and clear? of course i'll do the OCLT test to confirm...

Just not sure at what point, if at all, do I need or have to bring it to mustard algae shock level if that's what I think I have?


thanks.
 
chuckdog said:
thanks poolmom. How do you maintain shock level during the very late overnight hours? Just wait until first thing in the am and get it back to shock level if it falls below? My pool is crystal clear and has been....aside from patches of what I believe is mustard algae that come back every day.

Is the trick the idea that "eventually" the pool will hold the shock level for an extended period? and the algae doesn't reappear for lets say 48 hours? then i'm free and clear? of course i'll do the OCLT test to confirm...

Just not sure at what point, if at all, do I need or have to bring it to mustard algae shock level if that's what I think I have?


thanks.
You are done with the shock process when you pass the three tests. See red lines in my sig.

Once done with normal shocking, you follow directions for Mustard Algae in Pool School here: pool-school/mustard_algae
 

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