Low ph and algae

[cdingess]

I shocked my pool due to what I think was algae at the bottom. When can I algaecide 60? Also, I always have a low ph. Please help.

[Watermom]

We need a lot more information to be able to advise you.

1. What kind of pool is it? What is the volume?
2. What size pump and what kind and size of filter?
3. Exactly what all have you added to the pool, meaning ingredients and not just product names like 'shock.'
4. What does the water look like?
5. Do you have a drops-based test kit? If so, what kind? Post current numbers.

If you don't have a good drops-based test kit:
The test kit that we think is by far the best is the Taylor K2006 or 2006C (better buy). Not available locally but you can get it through this link that takes you to Amazon: http://pool9.net/tk/

But, in the meantime, go to Walmart and see if they have the HTH 6-Way drops-based kit (no test strips!) and get that. If they don't, get an OTO/Phenol Red kit (yellow and red drops) instead. Use it to test and then post your numbers. Also while you are at WallyWorld, get several jugs of their generic 8.25% bleach and a couple of boxes of 20 Mule Team Borax (laundry aisle).

Repost with requested info and then someone here can try and help you.

(Until you registration is completed, you won't be able to see the rest of the forum while you are logged in. So, copy that link and then paste it into a browser window after you log out.)

[cdingess]

Here are my numbers from my kit ph 6.8 oto 10 alk 40 hardness 80 cya 41.

I shocked with hth yesterday and used algaecide 60 11oz last week Wednesday and Tuesday last week I used shock hth. My filter is 150 sq ft cart filter it's 24-26 above ground pool. The water never got green-green but had green spots. I vacuum e them up and a day or two they come back. I put less than half box mule to raise the ph up. It holds 16000 gallons. I have purchase all that you have told me too. I was using the test strips but will stop. I am using the floater with 3 inch chlorine tabs.

As of today 7-614 I shocked yesterday and vacuumed yesterday and put some mule in.
What else can I do to prevent that coming back??! Please help. Christina

[PoolDoc]

If you're pool is 26' x 4', the volume is ~14,000 gallons. If it's 26' x 4.5' (54"), it's ~15,000 gallons.

Do this:

1. Check the chlorine again. If the level is greater than 5.0 ppm, you'll need to get a gallon of *DISTILLED* water are Walmart. Mix 1/2 of pool water with 1/2 cup of DISTILLED and retest the pH of the mix. If you use DISTILLED (not bottled, spring, etc.) your pH reading should be about accurate. The problems that high chlorine can screw up phenol red pH testing.

2. Your pH is too low. A pH reading of 6.8 may mean 6.8 . . . OR, it can mean anything below 6.8, such as 5.0 which will damage your liner rapidly. Add 1 box of borax at a time, to the skimmer with the pump running. Do NOT remove the skimmer basket. Retest your pH after 2 hours of pump run time. Continue adding borax until the pH is 7.0 or greater. (Keep up with how many boxes of borax you add - it may matter later!)

The water never got green-green but had green spots. I vacuum e them up and a day or two they come back.

3. You're describing mustard algae. It's VERY chlorine resistant. This page covers some more details => http://pool9.net/algae-m/.

4. Meanwhile, each time it re-appears add 2 gallons of bleach in the EVENING and then brush all the spots.

5. Polyquat (algaecide 60) is not particularly helpful with mustard algae. It certainly won't hurt, but won't fix the problem, either.

6. Question: are you near open water? (I'm trying to figure out why some pools are prone to mustard algae, and others aren't.)

Post your results from pH testing, and let us know what you think after you read about the mustard algae options.



4. Retest your alkalinity, once you get your pH above

[cdingess]

Ok I did what you said and my ph is now 7.5 after 1 box boraxe yay!!!! The oto was >5 so I put 2 gallons of bleach in. I'll check both tomorrow evening. Hopefully it's all gone. Also, I do have a large pond in the property. I haven't had the solar cover on the pool since this all began, would it be safe to put on if I hear it's going to rain? Thanks Christina

[PoolDoc]

Yes, you can cover it. But make sure 10 - 20% of the pool remains uncovered.

When you are removing 'goo', including algae, volatile chlorinated compounds form ('stinky' chlorine). They can't leave a fully covered pool.

And . . . be SURE to keep the chlorine high during the rain; algae often gets ahead of pool owners when it's raining, because the pool gets ignored.