Problem with cloudy in-ground pool. Brown residue on liner.

I have an 18x32 In ground pool, approx 25,000 gallons with sand filter and vinyl liner. The water is cloudy and there is a brown sand-like residue on the liner and it keeps returning after cleaning. We use an Aquabot for vacuuming. The last test readings showed everything normal but low CYA.
I also just added an HTH product called a clarifier. This seemed to make things worse.
Do I have mustard algae and if so what are my next steps? Is the aquabot making things worse?
I just bought 2 CYA producst that are coming in the mail in the next day or 2.

Need your help.

Quote:

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Originally Posted by crosspoint

. The last test readings showed everything normal but low CYA.

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Can you please post a set of test results, taken with a drop-based kit (no strips!) for us to look at? "Normal" can be many different things, depending on whose standards you're following. By looking at test results, we're more apt to be able to give you good advice. What do you use for chlorination? Is the sand-like residue hard, like scales, or like clumps of dirt, slimy, etc? Does the brown form just on the bottom of the pool, or also on the sides? Does it brush away easily?What is the source of your fill water? Any metals in the water?

I would not add anything else to the pool, except chlorine, until we get a chance to take a look at your test numbers. Clarifiers have their place in pool care (some of them, anyway) but I don't think it's going to help your situation, and it may actually make things worse.

Do you have a drop-based test kit of your own? If not, you'd be doing yourself a favor to get one, so you don't have to rely on pool store testing.

Also, can you take a few seconds and fill out this short form about your pool so that we don't waste a lot of time and posts back and forth getting the basic info we need in order to help?

Pool Chart Entry Form
Pool Chart Results

Welcome to the pool forum!!

Here are the pool readings.
Test Kit for PH and Chlorine is an HTH OTO kit.
Other reading were taken with HTH test strips.

PH 7.6
Alkalinity 80
Hardness 200-400
CYA 30
Free Chlorine 0-.5

Go ahead and answer the rest of the questions that Janet (Aylad) asked you in her post above. That will make it easier for us to help you.

What do you use for chlorination? Tablets in a Hayward Chlorinator and chlorine shock.
Is the sand-like residue hard, like scales, or like clumps of dirt, slimy, etc? Greenish brown stain.
Does the brown form just on the bottom of the pool, or also on the sides? On bottom and sides including stairs.
Does it brush away easily?It brushes away easily.
What is the source of your fill water? Fill water is well.
Any metals in the water? Not sure if any metals in water.
We have been adding a lot of water to the pool. Not sure if we have some kind of leak. Yet another issue.

The browning staing sounds like iron staining, which many people with well water have problems with. Try getting one of your trichlor tabs, or a vitamin C tablet, and rub it on the stain and see if it makes a difference.
Janet

Quote:

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Originally Posted by aylad

The browning staing sounds like iron staining, which many people with well water have problems with. Try getting one of your trichlor tabs, or a vitamin C tablet, and rub it on the stain and see if it makes a difference.
Janet

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And note which one of the tabs made a difference if either one did. That will be a clue as to what is causing the stain.

The brown residue started out as what looked like "sand" mostly in the seams of the liner. On one day the entire bottom of the pool had a layer of this stuff and when I put the Aquabat cleaner in you could clearly see the tracks of where it was cleaning.
After I put the HTH clarifier in and ran the pump ovrnight the next morning the pool seemed clear but wth the residue on the liner. After putting in the Aquabot and running for awhile the water clouded up.

I am pretty sure we do not have much iron in our well water. We test it often and use it as our
potable water source. There are no iron stains where we use the sprinkler, etc.

Could there be another issue?

Quote:

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Originally Posted by crosspoint

After I put the HTH clarifier in and ran the pump ovrnight the next morning the pool seemed clear but wth the residue on the liner. After putting in the Aquabot and running for awhile the water clouded up.

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Sounds like the clarifier settled it out, but then the vacuum re-suspended it in the water. I'm guessing it's really NOT sand-like (heavy, sinks rapidly, can be felt as grainy) but more dust-like (not heavy, floats away if you create a current by waving your hand or pool brush, can NOT be felt as individual grains)

Questions:

1. Have you cleaned your filter this season (as in, took it apart and washed clean)? <= Forget this; I misread the chart, and thought you had a DE filter.
2. Do you have a manual vacuum, like this:

Poolmaster 27514 Classic Full View Triangular Vinyl Liner Vacuum @ Amazon OR
Poolmaster 27200 Premier Heavy-Duty Flexible Metal Handle Vacuum @ Amazon

Hydro Tools 8365 8- to 16-Foot Adjustable Fluted Premium Fluted Telescopic Pool Pole, White @ Amazon
Poolmaster 33430 Premium Vacuum Hose with Swivel Cuff, 30-Feet by 1-1/2-Inch @ Amazon

3. Do you have a multiport valve on your filter?
4. Is it light tan (ie, the color of dirty DE powder)? <= Forget this one, too.
5. Have you tested your filter with DE powder, to see if it 'leaks' dirt back into the pool? <= New question

The residue is more dust like and floats away if you make a curent.
I stopped using the Aquabot and went to manual vacuuming.
I backwash amd rinse after each vacuuming session.
I also shocked the pool with liquid chlorine an am running the filter continuously.
The pool water is clear with the following readings.
PH - 7.5
FC - 5 - OTO
Alkalinity - 80
Hardness - 300
CYA - 30.
Still vacuuming up some remaining residue.