SLAMMED Twice. Algae back again.

[colosports]

I'm puzzled. I read the other threads and thought I had a good understanding of how to SLAM my pool and get it clear again. Apparently I'm doing something wrong because the algae are back.
First of all, my pool is an Intex above ground pool. It's 24'x12'x52" and holds about 8500 gal. I also have an Intex SWG. I'm in the Tampa Bay, Florida area and the pool gets about 12 hours of direct sunlight each day. Pump runs for 12 hours from 9am to 9pm.

I had the pool for about one month and the pump went bad. Had to wait about a week for them to delivered a replacement pump.
During that time the pool turned green. I ran the pump and SWG nonstop in boost mode for 3 days. It turned for green to cloudy. the water didn't improve or turn crystal clear so I proceeded to SLAM the pool.
After 4 days of the SLAM, CC was 0.5ppm. The water was blue (bit cloudy) but not crystal clear. The OCLT pass (loss of 0.5ppm). I let the FC drop down to 5ppm and it was crystal clear for 2 weeks.

We were getting a lot of rain. And I was not brushing the pool weekly like I should. The pool turn green again. So I thought maybe I didn't SLAM the pool long enough. My fault, so on to attempt #2.
Initial readings on SLAM #2
FC 6.0
CC 0.5
CH 225
TA 100
CYA 40
PH 7.5

Target FC for SLAM was 16. Majority of the time, I had the FC ranging from 16 to 20. The last two days of the SLAM, I allowed it to dip down to 14.5.
After 8 days, the results were:
FC 14.5
CC 0.5
CH 200
TA 70
CYA 30
PH 7.2
CYA went down because I backwashed. I also vacuum/brush the walls and the floors with the water going out to the streets. Top off with water. We had one night of heavy rain (hope this did not add to the problem).
After 8 days, CC was at 0.5. I completed the OCLT and it passed for 4 straight days. I wanted to make sure all the algae was gone and didn't want to stop the SLAM too early as in my first SLAM. The water again was clear but not crystal clear. It had a tint of blue. I used the 8.25% Clorox bleach so I was thinking because the it was concentrated, it would be a bit bluish. I drop a dime in the pool and can see if it's heads or tails.

After a few days, as the FC dropped to about 8.0, it was crystal clear again. I thought the SLAM was a great success.
So I got the CYA up to 80.
The PH was a bit low at 7.2. So I added some Borax to bring it up to 7.5
Patted myself on the back. Now time to enjoy the pool!

It has been clear for a week. I went to brush the pool this past weekend and noticed a bit of algae coming off my pool brush. That's weird. I thought I did everything right.
Now it's starting to turn green again. Today, I took the water sample to the pool store so I can compare their test with mine.
Their results:
FC 4.0
CC 0.0
CH 225
TA 100
CYA 60
PH 7.2
Salt 3200
TDS 5000

My test from today (I just added some Borax this morning, so I'm not sure if the number are accurate yet). May have to test it again in the morning when the Borax settles:
FC 5.0
CC 0.5
CH 200
TA 100
CYA 80
PH 7.8

Any guess to why the algae is back? Am I doing something wrong?

 

[pabeader]

It sounds to me like you are not getting enough chlorine from your SWG. Since you are running it during the day, I wonder what your FC is first thing in morning? Before the pump kicks on. I know we normally say to test after the pump has been on but your SWG is tied to the pump.

 

[chiefwej]

BTW: why did you add Borax? A pH of 7.2 is fine. In fact anytime mine gets above 7.8, I add acid to bring it back down to 7.2.

 

[Catanzaro]

It has been clear for a week. I went to brush the pool this past weekend and noticed a bit of algae coming off my pool brush. That's weird. I thought I did everything right. Now it's starting to turn green again

A few items:

You can only work on your testing and not the pool store. Your figures are different from the pool store. Algae, when brushed is broken up and floats in the water so chlorine can get to work. Pictures would be helpful.

Maybe this is a circulation problem. Can you take some pictures? I am assuming you have no main drain, possibly a skimmer and a few returns. You are maintaining your minimum FC. If you brush daily and pool remains clear for weeks, then maybe circulation could be the issue.

And I was not brushing the pool weekly like I should. The pool turn green again.

It appears that you are on track with taking care of pool and possibly the brushing part (at least a few times a week) is what is needed to keep algae in check.

Question: What test kit are you using?

 

[duraleigh]

Welcome to the forum.

These issues are always tough to solve. We know TFP works. It's proved in thousands of pools every day.

Algae simply does not grow in a properly chlorinated pool. Are you testing your FC daily with an OTO test? You should be, because at some point, your FC is getting low enough to let your pool grow algae and you must catch those low points and make sure they NEVER happen.

My advice would be to stay out of the pool store. What would you have gained if their results had been drastically different from yours......only confusion, I'll bet. A prime tenant of TFP is to trust your own testing....always.

I agree your borax was not necessary. You raised TA along with the pH and I would carry a TA of about 60-80 with an SWG. That doesn't have anything to do with your algae issue but it's worth mentioning in your overall management of your pool.

 

[colosports]

I'm using the TF-100 test kit.
I know the FC minimum is fine. I been keeping an eye on it daily.
SLAM #2 was completed on 9/4. Here are the results of my daily FC levels:
9/4 4:45pm FC 14.5
9/5 10am FC 13.5
9/6 4pm FC 8.0
9/7 8am FC over 5.0 (Chlorine Test (OTO))
9/8 815am Added 2 lbs CYA to get if from 30 to 60
9/9 9am FC 8.5 Also added 1 lb CYA to bring CYA from 60 to 75
9/10 730pm FC 7.0
9/11 Added 4 boxes of Borax and 112 oz of Acid to offset the PH and TA rise.
The lowest FC level is 5.0
The FC minimum is 3.0, so the FC been above the minimum all week.

Regarding the Borax, I read this: So you want to add borates to your pool--Why and How
Seems like it would be beneficial so I gave it a try. My Borax level should be around 31 according to Pool Math.

My pool has two intakes ports and one return jet. Maybe my circulation is bad. I had it pointing downward toward the corner and away from my the intake but I adjusted it to have it pointing away the intake and a tad below the water surface to get more water movement into my floating skimmer. I will play with the angle to see if that helps. I usually have the skimmer connected to one of the intake ports because bugs build up quickly. I connect the Aquabug once a week to vacuum the floor. Is the Intex Deluxe Skimmer restricting my circulation or the angle of the return jet wrong?

 

[MarianParoo]

Maybe a silly question, but did you have your SWG off during your SLAM?

 

[colosports]

Yes. The SWG was off the entire SLAM process.

 

[MarianParoo]

Just wanted to make sure. You never mentioned it specifically, and that would have been an easy explanation....

And you also pulled your ladders and checked in the skimmer weir and all that?

You want your jet to point down and away from the skimmer to help create a whole pool circulation.

 

[colosports]

- - - Updated - - -

Just wanted to make sure. You never mentioned it specifically, and that would have been an easy explanation....

And you also pulled your ladders and checked in the skimmer weir and all that?

I removed the ladder. The only place that I didn't clean was inside the jet return. I will remove it tomorrow and check.

 

[MarianParoo]

If you see anything at all in there, use a toothbrush to break the algae's biofilm just like a pool brush would do on the larger surfaces.

Your minimum FC is not 3, but 4. Did it ever drop below 4?

I am just reaching for straws here because it sounds like you have done everything correctly.

Since you saw algae on your pool brush, you will need to slam again. I am just trying to look for anything that might keep you from success on this next go-round.

 

[Crackerjack4u]

Hello Colosports, and Welcome to TFP,

I know this isn't your 1st Slam, but, hopefully, together we can do everything we can to ensure it is your last.

Again welcome to TFP. We look forward to helping you get this issue resolved. Have a wonderful night.

 

[colosports]

If you see anything at all in there, use a toothbrush to break the algae's biofilm just like a pool brush would do on the larger surfaces.

Your minimum FC is not 3, but 4. Did it ever drop below 4?

I am just reaching for straws here because it sounds like you have done everything correctly.

Since you saw algae on your pool brush, you will need to slam again. I am just trying to look for anything that might keep you from success on this next go-round.

The lowest the FC fell to was 5 (yesterday).

I'm trying to figure out what other factors may be.
When I removed my ladder and skimmer, I did not see any algae. Since the equipment was out of the water for a week, is it safe to assume that any hidden algae would die from the lack of water?
My other thing is the Aquabug, can the algae live inside the vacuum hoses or inside the Aquabug?

Any suggestions before I start SLAM #3. I do not plan on using the skimmer or Aquabug during the SLAM like I previous did. I'm trying to eliminate any additional factors that may be contributing to the algae.

 

[colosports]

A few items:

Maybe this is a circulation problem. Can you take some pictures? I am assuming you have no main drain, possibly a skimmer and a few returns. You are maintaining your minimum FC. If you brush daily and pool remains clear for weeks, then maybe circulation could be the issue.


It appears that you are on track with taking care of pool and possibly the brushing part (at least a few times a week) is what is needed to keep algae in check.

Question: What test kit are you using?

My pool only have the two intake and one return jet. No drains. I brush it twice a week. Do I need to brush it more often? What kind of test can I do to check if it is a circulation issue?

 

[kschmidt1]

I believe you should put anything that has been in the algae water, hoses, brushes, toys,etc in with the slam to destroy any trace of algae. I,m sure Aquabug would qualify as well.

Karen

 

[Paul.]

Hi everyone,

I am new to this as well and wanted to give my opinion.

I have been reading the posts and see that your CYA is at 75. At that level for a SWG pool, the slam level should be 29.

As I was reading, i noticed that you only get to 14.5.

Im thinking that this is the problem.
As I understand it, SLAM is Shock Level And Maintain, and I see that you have not gotten close to the shock level.
Since the FC isnt high enough during the slam to kill everything, I am assuming that there are residual algae there, even if your CC is at 0.5 or less.
Also since the FC is too low for the SLAM, would that make the OCLT invalide.

 

[singingpond]

View attachment 42657

That pattern of intakes and return, all pretty close together in one side of a rectangular pool, looks like a huge challenge as far as getting good circulation. I don't know if there is a good solution, short of modifications of pool and equipment. More frequent brushing than usually recommended, maybe, to compensate for circulation challenges?

Edited to add: Maybe it's worth sampling from several spots in the pool for comparison FC tests, especially down in the corners farthest from the return, where it seems circulation might be bad. Some people use a length of pvc pipe to sample deeper water - lower it in gently, cover the top end of the pipe, lift out... If you see differences in chlorine levels in different parts of the pool (all sampled at about the same time for fair comparison), that would be interesting to know.

 

[duraleigh]

Looking at that pic, singing pond is on to something. That is an inadequate design for decent circulation. The chlorinated water must continually circulate throughout the entire pool and I do not believe your setup comes close.

Secondly, Intex pumps and filters are barely adequate to do a good job. I see you have the 2500 gph pump and a decent filter but, even so, they are really very small to do an adequate job on that size pool.

I think you can have a clean, clear pool with what you have but you will have to reroute your circulation and run it absolutely 24/7 to keep the pool sanitized.

I don't think I would SLAM until I got the circulation issue fixed.

 

[Paul.]

I'm using the TF-100 test kit.
I know the FC minimum is fine. I been keeping an eye on it daily.
SLAM #2 was completed on 9/4. Here are the results of my daily FC levels:
9/4 4:45pm FC 14.5
9/5 10am FC 13.5
9/6 4pm FC 8.0
9/7 8am FC over 5.0 (Chlorine Test (OTO))
9/8 815am Added 2 lbs CYA to get if from 30 to 60
9/9 9am FC 8.5 Also added 1 lb CYA to bring CYA from 60 to 75
9/10 730pm FC 7.0
9/11 Added 4 boxes of Borax and 112 oz of Acid to offset the PH and TA rise.
The lowest FC level is 5.0
The FC minimum is 3.0, so the FC been above the minimum all week.

I am new to this as well and wanted to give my opinion.

I have been reading the posts and see that your CYA is at 75. At that level for a SWG pool, the slam level should be 29.

As I was reading, i noticed that you only get to 14.5.

Im thinking that this is the problem.
As I understand it, SLAM is Shock Level And Maintain, and I see that you have not gotten close to the shock level.
Since the FC isnt high enough during the slam to kill everything, I am assuming that there are residual algae there, even if your CC is at 0.5 or less.
Also since the FC is too low for the SLAM, would that make the OCLT invalide.

I am also curious to know what % your SWG is at? and how long you are running your pump on a daily basis.
I noticed from 9/6 to 9/7 you lost almost 3ppm FC overnight, which is showing that you still have something living in the pool. Assuming that you are running the SWG properly, this seems like a big loss.

 

[Catanzaro]

My pool has two intakes ports and one return jet. Maybe my circulation is bad

If this fits your return, I would give this 360 degree rotating return a shot. It moves water in all directions. Is it all possible you could create extensions with fittings, PVC, glue, etc.? Maybe It appears that everything is close together from the picture.


Amazon.com: Circulator 10022a Automatic 360 Rotating Swimming Pool Cleaner Jet with Water Control Bottom Cap: Patio, Lawn Garden

Only other option is to constantly brush the pool to keep everything in the water so chlorine can do its job. Maybe call the manufacturer and speak with them to see if they can come up with any ideas. Possibly adding a secondary set up on the other side to do the same thing. Keep us posted.