Mustard Algae

I have had perfect clear water all summer. The numbers were all good. The only thing high was my ph 8.0-8.2
Two weeks ago added muriatic acid and brought it down to around 7.4
I now have light tan algae on the bottom.
Was thinking on talking my ph back up to 8


I also can't find any of my posts I started. Does that happen automatically when you don't post for awhile?




Thanks SL

Don't know about the posts. PoolDoc or Watermom should know.

Lowering your pH makes you chlorine MORE effective, not less. But without your FC, CC, TA, CH and CYA readings it's hard to tell.

But raising your pH will NOT kill algae. Raising your chlorine level will.

fc 5
cc 0
Cya 60
ph 7.4
ta 120

numbers seem good to me
Have not done anything all summer but add 1/2 gallon (bleach) or alittle less each day.

Only change recent was dropped my ph some

Water still clear, and we have had a hot spell lately



SL

Sorry, but if your CYA is 60 and your FC is 0, you are BEGGING for an algae bloom--and clearly have one. I would immediately put 7 jugs of 8.25% bleach (if it comes in 121 oz bottles) in your pool and get your FC up to 20. You need to shock your pool to at least 20 and keep it there til it is clear. The ONLY thing raising your pH will do is make it harder for the chlorine to do its job.

Given your numbers and description, the prescription is straight forward.

Quote:

---

Originally Posted by Straightleg

fc 0
cc 5
Cya 60
ph 7.4
ta 120

numbers seem good to me
Have not done anything all summer but add 1/2 gallon (bleach) or alittle less each day.

Only change recent was dropped my ph some

Water still clear, and we have had a hot spell lately



SL

---

Fixed it:
I typed wrong
My fc is 5
and my cc is o

.
Here's a link to your old posts http://www.poolforum.com/pf2/search.php?searchid=48573

FC of 5 is too low for your CYA level anyway. CarlD will give you details :D

Quote:

---

Originally Posted by FormerBromineUser

.
Here's a link to your old posts http://www.poolforum.com/pf2/search.php?searchid=48573

FC of 5 is too low for your CYA level anyway. CarlD will give you details :D

---

I cant get in to that link. I am locked out for some reason.
My book in the k-2006 says ideal numbers. I am at every one. They say don't let your CYA soar up, so I have been careful with that. Watermom told me to keep it between fc 3-6. I have done that all summer.
So now that you say this I am at a loss



SL

OK.
Here's what I think happened: Your pH went in to the 8s, effectively shutting down most of your chlorine's ability to perform. (Somewhere we have a table or formula on that).
That allowed algae to form. The answer is STILL to take your FC up to 20ppm (using 5 121oz jugs of 8.25% bleach, instead of 7).

The only other possibility is that something else unrelated to chlorination is going on and it's not algae. But I don't think so.

Quote:

---

Originally Posted by Watermom

With a CYA of 50, you want to try and keep your chlorine between 3-6 all the time. Here is what to do. Each evening, test the chlorine. Add enough bleach to take your chlorine back up to 6ppm. The next evening, if you find that your chlorine has dipped below 3ppm, take it up to 7ppm when you dose with bleach. The goal is to find out how high you need to take it so that it never drops below the minimum by the next evening. You will soon learn your pool's pattern.

In case you need the Best Guess Chart again, it is here: http://pool9.net/cl-cya/

---

I think this is the post to which you were referring. Your CYA is now 60 so you need to bump up WaterMom's original minimum recommendation for maintenance.

HOWEVER, you now have algae. CarlD will advise you what to do but in the meantime, reread the Best Guess chart linked above.

Sorry, Carl. We posted at the same time....

Here is your thread where we helped you get the chemistry going. http://www.poolforum.com/pf2/showthr...ars?highlight=

This is the one about your pool pump hating you! ;) http://www.poolforum.com/pf2/showthr...-me?highlight=

Please let me know if you cannot access these links.