High alkalinity - but PH level ok

[birdman]

I have an in-ground pool with just over 30k gallons and the deep end is a little cloudy.

The alkalinity is very high but the PH level is normal. The total chlorine is low too.

Any suggestions? Thanks so much - I'm a rookie at this.

[Watermom]

Words like high, low and normal don't give us enough information to be able to help. Can you give us some current water testing result taken with a drops based kit? The kit we recommend is the Taylor K-2006 or 2006C which you can get through the testkit link in my signature below. It is only available online, so you'll need something to use in the meantime. Get a cheap OTO (yellow drops) / phenol test kit, or if available at YOUR Walmart (check availability), get the HTH 6-way DROPS test kit, which is compatible with the Taylor K2006. Test the pool as soon and you can, and post the results. If you get the 6-way kit, ALSO test the water you FILL the pool with, especially if it's a well, and post THOSE results as well. (The HTH is the best available kit you're likely to find locally, but it's not the K-2006. It can only provide rough measurements chlorine levels above 5 ppm, and it measures "TOTAL" hardness, rather than "CALCIUM" hardness, which is not ideal.)

It's much easier to answer your questions, when we know something about your pool. We often 'waste' the first few posts back and forth collecting information. So, please complete our new Pool Chart form -- it takes about 30 seconds, but will save much more than that.

Pool Chart Entry Form
Pool Chart Results

Welcome to the Pool Forum!

[birdman]

Thanks - I filled out the entry form.

Total chlorine is 3.1
pH is 7.3
TA is 170
Calcium hardness is 300

Plus, I forgot to mention there is a yellow-ish dust (in patches) at the bottom of the pool. Is that mustard algae?

Is there more information needed? Thanks so much.

[PoolDoc]

How are you testing? Those don't look like values from a kit.

Anyhow, assuming those values are correct, you'll want to keep your pH in the 7.0 - 7.2 range for now. If you do -- it will require repeated additions of acid -- your TA will drop.

You omitted one of the the most critical measurements: CYA or stabilizer. You need to find out what your level is, read the Best Guess page linked in my signature, and then adjust your chlorine levels accordingly. Given that you probably DO have mustard algae, you will almost certainly need a FAS-DPD chlorine test in order to manage the correct chlorine levels. Read the test kit info page linked in my sig.