Black Algae & Balancing

[snichols1219]

Turned the SWG off. Tested the FC and it's 34. According to chart should be 28 (I added the amount of bleach the Pool Math told me to based on it's calculations of how many gallons the pool is). So, do I add water to bring that down or let it fall on it's own? It's supposed to rain this afternoon for a couple of hours. Also brushed it again ~ it already looks so much better!

Agree, check the FC every hour or two and add bleach to bring it back up to where it needs to be.

If you can, go ahead and turn off your SWCG as at this point you need massive amounts of chlorine and all the SWCG is add is minute amounts. Save the life of the salt cell.

 

[WASP]

Above shock level is OK. Just don't let it drop below shock level for any length of time.

 

[tim5055]

Above shock level is OK. Just don't let it drop below shock level for any length of time.

I agree, above shock level is OK within reason. In a SLAM this FC is going to come down fairly fast.

So, you added the amount Pool Math said and got a higher result than you expected. This means one of two things:

* Your pool volume is actually a little smaller than you thought
* You are using a chlorine source with a higher % of chlorine than you thought.

 

[snichols1219]

I'm going with volume is smaller. I have always said it was ~22,000 gallons and I base that solely on my water bill when we initially filled the pool (took the difference of that months usage and our average usage). When I put the dimensions (accounting for an average depth as instructed and an average width since it's free form) in the calculator it gave me 25,400 gallons. I'm going to go back to my estimate of 22,000. I know the chlorine % was correct, I read the bottle on that one and changed it accordingly in the math program.

I agree, above shock level is OK within reason. In a SLAM this FC is going to come down fairly fast.

So, you added the amount Pool Math said and got a higher result than you expected. This means one of two things:

* Your pool volume is actually a little smaller than you thought
* You are using a chlorine source with a higher % of chlorine than you thought.

 

[tim5055]

I'm going with volume is smaller. I have always said it was ~22,000 gallons and I base that solely on my water bill when we initially filled the pool (took the difference of that months usage and our average usage). When I put the dimensions (accounting for an average depth as instructed and an average width since it's free form) in the calculator it gave me 25,400 gallons. I'm going to go back to my estimate of 22,000. I know the chlorine % was correct, I read the bottle on that one and changed it accordingly in the math program.

As you go along if you watch your chemical additions and effects on the pool you will probably be able to narrow down your volume. It is not beyond the realm of possibility that you got "fresh" chlorine that was a little higher % than marked.

 

[kimkats]

You have a good handle on what you need to do already! Good job!

Keep brushing as well as adding FC according to your testing. Do not worry about testing any thing else while you SLAM.

Kim

 

[snichols1219]

For the most part the pool looks AMAZING! I have a few spots that appear to be slower to vacate or just really stubborn & don't seem to be doing much. Of course these are on the bottom of the pool, and while I feel like I'm doing a stellar job making sure I really scrub them, maybe since I'm having to use the pole I'm not or my perception is off?

 

[kimkats]

With them being on the bottom it IS going to be harder and take longer for them to leave as you just cannot put as much pressure on them when you brush. Keep it up and over time (how long I do not know) they will go away.

Kim

 

[snichols1219]

And until that time keep the chlorine at shock level and pumps running 24/7?

With them being on the bottom it IS going to be harder and take longer for them to leave as you just cannot put as much pressure on them when you brush. Keep it up and over time (how long I do not know) they will go away.

Kim

 

[snichols1219]

I think I'm done. Pool looks amazing except for 1 spot on the bottom in the shallow end that is doing absolutely nothing. No matter how much or how hard I scrub it has not changed one bit. I have some black spots in the plaster and I'm thinking that's what that one is. The ones that are up on the tanning ledge where I can get to them easily are obviously not algae, but black specs of varying size. So, do I now let the chlorine level drift back down? And quit running the pumps 24/7?

 

[JoyfulNoise]

I think I'm done. Pool looks amazing except for 1 spot on the bottom in the shallow end that is doing absolutely nothing. No matter how much or how hard I scrub it has not changed one bit. I have some black spots in the plaster and I'm thinking that's what that one is. The ones that are up on the tanning ledge where I can get to them easily are obviously not algae, but black specs of varying size. So, do I now let the chlorine level drift back down? And quit running the pumps 24/7?

Shannon,

Are you measuring your overnight chlorine loss? One of the SLAM exit criteria is <1ppm FC loss overnight as measured when the sun goes down and just before sun up. You need to do this test because clear water is not an indication of clean water. If your overnight chlorine loss is greater than 1ppm, you have to keep at it.

As for those spots, if they still do not go away, then you can try an ascorbic acid (vitamin C) test to see if they are metallic in nature. But you can only do that after your SLAM is complete and the pool water is chemically balanced.

 

[snichols1219]

Shannon,

Are you measuring your overnight chlorine loss? One of the SLAM exit criteria is <1ppm FC loss overnight as measured when the sun goes down and just before sun up. You need to do this test because clear water is not an indication of clean water. If your overnight chlorine loss is greater than 1ppm, you have to keep at it.

As for those spots, if they still do not go away, then you can try an ascorbic acid (vitamin C) test to see if they are metallic in nature. But you can only do that after your SLAM is complete and the pool water is chemically balanced.

I am doing to overnight loss tonight to check it out and see where I stand in that regard ~ I knew that was a requirement before stopping the SLAM. Will having any debris in your skimmers or vacuum bag affect that result? I just cleaned them all out, but just curious.

 

[JoyfulNoise]

I am doing to overnight loss tonight to check it out and see where I stand in that regard ~ I knew that was a requirement before stopping the SLAM. Will having any debris in your skimmers or vacuum bag affect that result? I just cleaned them all out, but just curious.

Best results will occur when everything is as cleaned as possible.


Sent from my iPhone using Tapatalk,16k gal SWG pool (All Pentair), QuadDE100 Filter, Taylor K-2006

 

[kimkats]

I am sorry I did not get back to your question.... I did not see it until just now

Yes you did the correct thing and it sounds like it shows!

I can't wait to see the results of the OCLT! Make sure to test your FC about a hour after adding your last dose. Leave the pump running so you can get your morning sample right after your first cup of coffee!

Kim

 

[MarianParoo]

The SWG is still off, right?

 

[snichols1219]

The results are in ~ overnight FC loss was 0.5! Yippee! Yes, SWG is still off. So, now for my list of questions:
I can set my pump schedule back up to it's regular running time?
Do I leave the SWG off until the FC gets back down to a more normal range and then turn to back on, or go ahead and turn it on?
I have always run my pumps in the day since that's when the majority of the swimming happens ~ is this best practice or should I run them at night?
For the sake of the life of the salt cell, am I better to run it at full throttle in the heat of the summer or cut it back and run pumps for longer? In the summer it runs at 100% for about 9-10 hours.
Did I read somewhere in all of this that I need to keep the FC at the higher end as general practice instead of the lower? I've always kept it about 3. I don't ever want to do this again!
And back to the question about the calcium. Pool store says 200-400 is the range, ABCs of Water Chemistry says 400 for a salt water pool. Mine was 220 at the start of this process. Once FC is back to normal range, should I be adding that to bring it up to 400?

 

[JoyfulNoise]

The results are in ~ overnight FC loss was 0.5! Yippee! Yes, SWG is still off. So, now for my list of questions:
I can set my pump schedule back up to it's regular running time?
Do I leave the SWG off until the FC gets back down to a more normal range and then turn to back on, or go ahead and turn it on?
I have always run my pumps in the day since that's when the majority of the swimming happens ~ is this best practice or should I run them at night?
For the sake of the life of the salt cell, am I better to run it at full throttle in the heat of the summer or cut it back and run pumps for longer? In the summer it runs at 100% for about 9-10 hours.
Did I read somewhere in all of this that I need to keep the FC at the higher end as general practice instead of the lower? I've always kept it about 3. I don't ever want to do this again!
And back to the question about the calcium. Pool store says 200-400 is the range, ABCs of Water Chemistry says 400 for a salt water pool. Mine was 220 at the start of this process. Once FC is back to normal range, should I be adding that to bring it up to 400?

Yes, pump schedule back to normal.

You can turn your SWG on now but it will take longer for the FC to drift down. You can let the FC drift down a bit and then turn it on. Totally up to you.

Run times can change seasonally. Some like to run at night to capture lower energy rates. Others like to run during the day. Basically it's up to you. Just make sure your run times are adequate to keep the pool clean and the FC up.

It sounds like your SWG is a little undersized for your pool. You need to run it to keep up your FC. That's critical.

3ppm FC is way to low for an SWG pool. Because you had BA, you should keep your FC at the high end and NEVER let it go below minimum. Follow TFP levels.

Check your fill water calcium. Don't worry too much about CH right now. It's a long term issue and there's rarely any need to add CH. Focus on keeping your FC at proper levels as that is your biggest task right now. Once you've mastered that, then you can worry about FC.


Sent from my iPhone using Tapatalk,16k gal SWG pool (All Pentair), QuadDE100 Filter, Taylor K-2006

 

[snichols1219]

Yes, pump schedule back to normal.

You can turn your SWG on now but it will take longer for the FC to drift down. You can let the FC drift down a bit and then turn it on. Totally up to you.

Run times can change seasonally. Some like to run at night to capture lower energy rates. Others like to run during the day. Basically it's up to you. Just make sure your run times are adequate to keep the pool clean and the FC up.

It sounds like your SWG is a little undersized for your pool. You need to run it to keep up your FC. That's critical.

3ppm FC is way to low for an SWG pool. Because you had BA, you should keep your FC at the high end and NEVER let it go below minimum. Follow TFP levels.

Check your fill water calcium. Don't worry too much about CH right now. It's a long term issue and there's rarely any need to add CH. Focus on keeping your FC at proper levels as that is your biggest task right now. Once you've mastered that, then you can worry about FC.


Sent from my iPhone using Tapatalk,16k gal SWG pool (All Pentair), QuadDE100 Filter, Taylor K-2006

Our rates are the same whether it's day or night, so no difference from that standpoint. The rate at which I have run it is what keeps the level up ~ or at least to a 3 ~ but I will adjust that accordingly to keep it higher now. Its a T-Cell 15, so not undersized, but that's what it takes to keep the level up. Always has been. The point of checking the fill water calcium is just to see how much it has?

 

[JoyfulNoise]

Our rates are the same whether it's day or night, so no difference from that standpoint. The rate at which I have run it is what keeps the level up ~ or at least to a 3 ~ but I will adjust that accordingly to keep it higher now. Its a T-Cell 15, so not undersized, but that's what it takes to keep the level up. Always has been. The point of checking the fill water calcium is just to see how much it has?

Well, now that you have SLAM'd your pool and knocked out the BA, you might find it easier to get to a higher level of FC with your T-15 cell. When the pool water starts to develop algae, many SWG pool owners find that they have to keep turning up the output to keep the FC up. Eventually the algae growth rate outstrips the SWG's ability to produce FC and then you see the FC crash. SO now that your water is in a better place, you may see that it's easier to maintain your pool water's FC with less output or less pump run time. Only time will tell.

As for when to run, again that's up to you. I typically run my pumps during the hotter, daylight hours to keep the FC up and then again for a few hours at night when there's no UV to burn off the chlorine (i.e., split schedule). That's one of the benefits of having an automation panel as it allows you to quickly and easily adjust schedules as-needed. Like I said, pump schedules are usually seasonal - in the winter, I only run my pump approximately 3 hrs/day. During the summer, it's more like 10 hrs/day. Only you can determine what's best for keeping the FC up and the pool clean.

Yes, the point of checking the fill water is to see how much calcium it adds to your pool. Being in Texas, you likely have fill water that is high in CH and, possibly, TA. If so, then there may be no need to add any CH as you can just let it drift up using your fill water. Now, if you also get lots of rain water overflow (it actually has to overflow the pool or you actually have to drain off excess water), then that will reduce your CH naturally. So you may be able to just leave it alone and see what it does. A CH of 220ppm, while a little on the low side, is not going to cause your pool to fall apart. Adding CH using calcium chloride is easy to do, but if you don't need to, then there's no reason to waste the money on it.

Once your FC levels drift back down below 10ppm, please post a full set of water test results. We can then help you balance out any remaining issues. Right now, your primary focus is maintaining a proper FC level in order to avoid anymore algae issues. Everything else is secondary to that. There is always a tendency for pool owners to see everything as a problem that needs to be fixed "right now" but that is simply not true. FC, pH and keeping your pool clean are all you need to care about at the moment.

Good luck,
Matt

 

[snichols1219]

Yes, the point of checking the fill water is to see how much calcium it adds to your pool. Being in Texas, you likely have fill water that is high in CH and, possibly, TA. If so, then there may be no need to add any CH as you can just let it drift up using your fill water. Now, if you also get lots of rain water overflow (it actually has to overflow the pool or you actually have to drain off excess water), then that will reduce your CH naturally. So you may be able to just leave it alone and see what it does. A CH of 220ppm, while a little on the low side, is not going to cause your pool to fall apart. Adding CH using calcium chloride is easy to do, but if you don't need to, then there's no reason to waste the money on it.

Once your FC levels drift back down below 10ppm, please post a full set of water test results. We can then help you balance out any remaining issues. Right now, your primary focus is maintaining a proper FC level in order to avoid anymore algae issues. Everything else is secondary to that. There is always a tendency for pool owners to see everything as a problem that needs to be fixed "right now" but that is simply not true. FC, pH and keeping your pool clean are all you need to care about at the moment.

Good luck,
Matt

I was adding water to the pool today so I tested the CH while I was at it. 225 directly from the fill line. In the past year we have had a ton of rain so the pool has overflowed many many times ~ and with 3 kids and all of their friends swimming we do a lot of water adding. I know I didn't add any calcium last year (pretty sure I did the year before though), so I guess what I have is from what I added and what's in the fill water.
FC was 12.5 today, but once it's below 10 I will post the full water test results.
Thanks!
Shannon