Mystery Substance

[benjohnsey]

I have this mystery substance that keeps appearing in my pool. It looks like dirt or mustard algae. I have treated for mustard algae in the last week but it kept accumulating during that process so I believe that’s ruled out. I suppose it could be pollen but it seems like a copious amount. I can vacuum or brush it easily and it clouds up but will return within an hour or so in the same spots and covers everywhere in the pool but concentrated on low spots or seams in the liner. It also seems to accumulate over night. It doesn’t seem to be sand. Any ideas? A picture is attached. Chemistry is generally normal based on the pool school recommendations. I have a sand filter.

Thanks!

 

[domct203]

I have this mystery substance that keeps appearing in my pool. It looks like dirt or mustard algae. I have treated for mustard algae in the last week but it kept accumulating during that process so I believe that’s ruled out. I suppose it could be pollen but it seems like a copious amount. I can vacuum or brush it easily and it clouds up but will return within an hour or so in the same spots and covers everywhere in the pool but concentrated on low spots or seams in the liner. It also seems to accumulate over night. It doesn’t seem to be sand. Any ideas? A picture is attached. Chemistry is generally normal based on the pool school recommendations. I have a sand filter.

Thanks!

Welcome to the forum!

What you are describing sounds like typical green algae. How exactly did you 'treat' for mustard algae?

I'm not clear on your 'generally normal' comment for the pool chemistry.

Please post a complete set of test results including:
FC
CC
pH
TA
CH
CYA

If you have a FAS DPD chlorine test kit, you can perform an Overnight Chlorine Loss Test to determine if this is algae.

 

[duraleigh]

Welcome to the forum

Looks like dead algae to me. Posting a complete set of test results will tell us more but I am pretty sure that is the problem and you will need to SLAM the pool to fix it.

 

[benjohnsey]

I’ll have to do a full test this evening. I use the tf test kit. Been following the forum for a few years. I treated for mustard algae as described in pool school, did a slam, raised chlorine to mustard shock level for 24 hrs with pump running full time. brushed multiple times bottom, sides, ladders, alcoves, etc. Soaked pool equipment. CC has remained <.5 before and the entire time during treatment. Before I started mustard algae treatment 3 days ago test results were as follows:

FC 6
CC 0 - .5
CYA 40
TA 110
PH 7.2

TA was a little high from tap water addition. I lowered ph to 7.2 and verified before starting the SLAM and mustard algae treatment.

Since I started treatment I’ve just been measuring FC and CC to maintain mustard algae levels but FC is drifting back down now.

 

[mknauss]

The mustard algae protocol is once a SLAM is complete. If your water is not clear (and the dead algae you show in the picture means the water is not clear) then the SLAM was never completed.

I would suggest returning to the SLAM protocol to completion.

Take care.

 

[JamesW]

Agree, continue SLAM.

 

[benjohnsey]

Will do. Maybe I am confused about what constitutes “clear” water. I thought I had met the criteria for the SLAM being done since my water did appear clear as well as the cc being below .5 and my overnight loss was below 1.

 

[mknauss]

This is a thread with a 'clear' pool -- TFP Clear in North Dallas - there is water in there

Also, if you have dead algae settling on the floor of the pool, the SLAM is not over.

Take care.

 

[kellyfair]

Ben, after you met those three criteria, what did you do?

 

[benjohnsey]

This would be the second SLAM since I opened the pool. When I opened it the water was green so there was definite algae. I did the first SLAM until the water appeared clear along with the other criteria.

After that I continued to have what I thought might be mustard algae so I did another SLAM and then went to mustard algae level for 24 hours. At this point it is coming down from that level but I am not sure anymore if that’s it since I still have this issue.

 

[benjohnsey]

Also after the first slam I maintained normal levels for a couple weeks.

Thanks for the advice everyone!

 

[benjohnsey]

Results now below:

Added 3qts 10% bleach to reach slam target of 14.



==========================================
Home
------------------------------------------
Build Type: Vinyl
Volume: 17000 gallons
------------------------------------------
Latest Test Result Summary:
FC: 11.0 (9 minutes ago)
CC: 0.0 (9 minutes ago)
pH: 7.2 (yesterday)
TA: 70 (9 minutes ago)
CH: 0 (9 minutes ago)
CYA: 35 (9 minutes ago)
==========================================

 

[mknauss]

We suggest using a CYA value that is rounded up to the nearest 10. The test vial you are measuring it with is logarithmic. I just fill the vial to 90, glance, see the dot, fill to 80, glance, see the dot, repeat.

Take care.

 

[benjohnsey]

Should I overshoot the suggest slam level to compensate for loss or just chlorinate to that level?

Also should I be vacuuming every day?

 

[mknauss]

No need to go above the shock level for FC. If you find it falling more than a few FC between testing, then test and dose more often.

Vacuuming will pick up the dead algae.

Can you fill out a signature? Read Pool School - Read This BEFORE You Post

Take care.

 

[benjohnsey]

OK, I've been running a SLAM since my last post. I believe my water is clean however I am still having deal algae or whatever this is appearing on the bottom of the pool. I vacuumed last night and within about 30 min it started to accumulate again. This morning it is back in its usual spots. There doesn't seem to be any change in quantity during the SLAM. It will continue to accumulate over several days all over the pool if history holds true.

My CYA is currently 30 and I have been running the SLAM at 12PPM FC.
My reading last night was 12 PPM with 0 CC after dark.
My reading this morning 12 PPM with 0 CC so I am not losing any at night. My water looks very clear to me, I can see every detail on the bottom and the pool light on and night shines through clearly and doesn't make the water look cloudy.

A picture after vacuuming last night:


And from this morning:



Any ideas or just SLAM longer?
Thanks for your help.

 

[mknauss]

Have you added any DE to your sand filter so that it can filter out any fines?

Read Pool School - Add DE to a Sand Filter

Take care.

 

[benjohnsey]

Have you added any DE to your sand filter so that it can filter out any fines?

Read Pool School - Add DE to a Sand Filter

Take care.

I have thought about trying that but have not. Seems like that’s what the next step would be.

Do you agree that my SLAM is done?

Where is a good place to get DE? I have seen some DE filter aid at Walmart but I am not sure if that is actual DE or something different. Anyone know?

 

[mknauss]

I would agree the SLAM is complete. No FC loss overnight and no CC in the morning along with clear water is what convinces me.

Just be sure to NOT use food grade DE.

Any neighbors with a DE filter? You do not need much. Typically just a 1/4 to 1/2 cup each time you do it.

Take care.

 

[benjohnsey]

I added some DE per the directions. I stopped at 2 cups although I didn’t get much of a psi increase. Is it possible it takes more?

I also have a glycerin filled pressure gauge and it has a relief needle on the side. If you pull it then it will generally start reading higher. Anyone know how that is supposed to work?

Thanks.