Stain or Algea? How to Treat?

[AUEngineer]

Hello!

First post, but have followed the TFP way for years… I have a unique issue (for my experience anyway) this time.

I was forced to leave the pool unattended for about a month due to work travel. When I returned, the pool had some clarity, but brushing showed heavy algae. The salt was extremely low and the the FC was 0. I raised the chlorine to slam levels and continued brushing. I kept chlorine at slam levels for about 5 days. Water finally cleared, crystal clear, FC didn’t drop overnight, so I discontinued adding Chlorine. Except I have some type of stain or algae throughout the pool. Please see photo. When I brush these spots, nothing happens. Suggestions of what to do?

Last TFP pool math log entries also attached. I’ve been working alkalinity down throughout this process. When I recently added acid to lower PH (and aerate to raise PH but not alkalinity) I saw a big spike in CC. I’m guessing the muratic acid made the chlorine more effective, so the result was a spike in CC? Which means I need to continue to SLAM? Is anyone familiar with this type of stain or tough algae? Will slamming for days on end eventually rid myself of this problem? Any faster way to do this or expedite the slam process? Addition of polyquat for example?

Thank you!

Can’t seem to get signature to work, so: 18K gal, IG vinyl, Hayward SWG.

 

[JohnT]

Welcome to TFP!

I think I’m seeing a brown color to the staining which might mean iron. You might want to check out this thread Ascorbic Treatment to rid Pool of metal stains

 

[Bperry]

Hello!

First post, but have followed the TFP way for years… I have a unique issue (for my experience anyway) this time.

I was forced to leave the pool unattended for about a month due to work travel. When I returned, the pool had some clarity, but brushing showed heavy algae. The salt was extremely low and the the FC was 0. I raised the chlorine to slam levels and continued brushing. I kept chlorine at slam levels for about 5 days. Water finally cleared, crystal clear, FC didn’t drop overnight, so I discontinued adding Chlorine. Except I have some type of stain or algae throughout the pool. Please see photo. When I brush these spots, nothing happens. Suggestions of what to do?

Last TFP pool math log entries also attached. I’ve been working alkalinity down throughout this process. When I recently added acid to lower PH (and aerate to raise PH but not alkalinity) I saw a big spike in CC. I’m guessing the muratic acid made the chlorine more effective, so the result was a spike in CC? Which means I need to continue to SLAM? Is anyone familiar with this type of stain or tough algae? Will slamming for days on end eventually rid myself of this problem? Any faster way to do this or expedite the slam process? Addition of polyquat for example?

Thank you!

Can’t seem to get signature to work, so: 18K gal, IG vinyl, Hayward SWG.

Your test results don’t seem to match what a Taylor kit outputs. Can you clarify where those numbers came from?

 

[AUEngineer]

Your test results don’t seem to match what a Taylor kit outputs. Can you clarify where those numbers came from?

The results you see are the ones I entered in TFP’s Pool Math phone app.

I used the LaMotte WaterLink Spin Touch Mobile Lab for those results. I use a handheld salinity meter (aligns well with Hayward SWG reading) and handheld thermometer to check salt and temperature (though I don’t do this every time I test).

 

[Bperry]

The results you see are the ones I entered in TFP’s Pool Math phone app.

I used the LaMotte WaterLink Spin Touch Mobile Lab for those results. I use a handheld salinity meter (aligns well with Hayward SWG reading) and handheld thermometer to check salt and temperature (though I don’t do this every time I test).

You’re free to do what you want of course but you’ll find that you can’t really do the SLAM process without the more reliable test kit. You’ll save yourself a lot of frustration by using one of those instead. Your CH is especially hard to believe.

 

[AUEngineer]

You’re free to do what you want of course but you’ll find that you can’t really do the SLAM process without the more reliable test kit. You’ll save yourself a lot of frustration by using one of those instead. Your CH is especially hard to believe.

Thanks for the responses thus far!

The CH readings shown are accurate—so are the other readings. I’ve checked the LaMotte Spin Touch against the Taylor Kit numerous times—the LaMotte Spin Touch results are aligned with the Taylor results every time I’ve checked.

For a liner pool, low CH is acceptable, therefore, I haven’t spent/wasted the money on the calcium to raise it. The CH in my pool water test results is very close to that of my makeup water.

I typically keep the CYA in the 70-80 range as TFP recommends for a salt pool, but as I mentioned before, salt was low (and therefore no chlorine from the generator), which also meant CYA was low. These low levels were caused from excessive rain overflowing the pool—and truthfully, in the off season, the salt and CYA levels were likely on the low side before I left for an extended period. Once I know I have the situation under control and won’t need to slam the pool more, I’ll raise the CYA back to proper salt pool levels.

The LaMotte test disks I’m currently using (4329-H) also test for copper and iron. Copper levels consistently run at 0.1 or 0.2ppm. Iron is the same at 0.1 or 0.2ppm. I’ve confirmed the copper value is correct using the LaMotte 3619 chemical drop test; however, I’ve never verified the iron readings (although I don’t have much reason to think it’s incorrect). So, I think these stains are likely not iron—however, I can certainly try some citric acid on some stain spots and see what happens (I keep some citric acid in the shop for flushing radiators).

Thank you!

 

[Bperry]

Thanks for the responses thus far!

The CH readings shown are accurate—so are the other readings. I’ve checked the LaMotte Spin Touch against the Taylor Kit numerous times—the LaMotte Spin Touch results are aligned with the Taylor results every time I’ve checked.

For a liner pool, low CH is acceptable, therefore, I haven’t spent/wasted the money on the calcium to raise it. The CH in my pool water test results is very close to that of my makeup water.

I typically keep the CYA in the 70-80 range as TFP recommends for a salt pool, but as I mentioned before, salt was low (and therefore no chlorine from the generator), which also meant CYA was low. These low levels were caused from excessive rain overflowing the pool—and truthfully, in the off season, the salt and CYA levels were likely on the low side before I left for an extended period. Once I know I have the situation under control and won’t need to slam the pool more, I’ll raise the CYA back to proper salt pool levels.

The LaMotte test disks I’m currently using (4329-H) also test for copper and iron. Copper levels consistently run at 0.1 or 0.2ppm. Iron is the same at 0.1 or 0.2ppm. I’ve confirmed the copper value is correct using the LaMotte 3619 chemical drop test; however, I’ve never verified the iron readings (although I don’t have much reason to think it’s incorrect). So, I think these stains are likely not iron—however, I can certainly try some citric acid on some stain spots and see what happens (I keep some citric acid in the shop for flushing radiators).

Thank you!

I really do wish you luck with it. Noone here will be able to help much with spintouch results. Lots of members have chase their tails with it before giving up.