Might need to SLAM???

[Nate4429]

Ok so still in my first summer as a pool owner and all was great until a couple weeks ago we had a week of rain and I noticed my chlorine levels dropping. I’ve got them back up but then back off to normalize my chlorine input and down goes FC. ? Here are my current numbers as of 5 min ago. I read the SLAM article posted on many of these posts and I’m ready to go to the store and buy a Crud load of bleach but I want to make sure I’m heading in the right direction. Here’s a pic of what I think is algae starting to build up on the bottom....

 

[Msch99]

Perform an over night chlorine loss test to find out for sure. OCLT.

Probably need slam, but you can make sure with oclt.

 

[Nate4429]

I opened the pool today and can just see the bottom of the deep end so it needs a SLAM ? It’s been crystal clear all summer until the rain for a week ? SLAM has been started! I’ve read the SLAM article. Any other tips or advice for SLAMing? Do I leave the solar cover on or off for the week it may take to do the whole process? Can we still swim during the SLAM? Anything else anyone has proven effective to help the process? Thanks to all on this forum! I’m always ready to learn ??

 

[IceShadow]

- Probably best to leave the cover off. You'll chew through more chlorine but it will let the CCs get burned up by the UV.
- You can swim with FC between minimum and SLAM level for your CYA, so long as you can see the entire pool bottom.
- The more often you can test the water and bring it back up to SLAM levels the quicker it will go.
- Recommend you pull everything you can out of the pool (ladders, etc.) and make sure to brush out any light niches, skimmer throat/weir door, etc. to find where the algae is hiding.

 

[Nate4429]

SLAM going well and I think I’m almost ready to try an OCLT. I didn’t official do the test last night but it only dropped .5 last night. So I will go through the actual test in the next night or two. I hoping to have this done before the 10th as we are going out of town for 10 days. I would like the house sitter to not have to worry about doing a SLAM while they are here.

What are some causes of an algae issue? Things were going very well all summer so far and then we had a week of rain and didn’t open the pool during that time so I could only think that th rain water on top of the solar cover sitting there and starting to get algae then when we pulled the cover off it goes into the pool. Is this valid? If so what can I do to combat that?

 

[thetekgeek]

The most likely cause would be that your FC level dropped below the minimum at some point. Once it dips below the minimum algae can grow. The longer it stays below the minimum, the algae is reproducing. By the time it gets to the point that you can see it, you're in a full blown bloom. Once you pass the SLAM, simply make sure you never drop below the minimum again and your pool will stay perfectly clear. Follow the FC/CYA chart - Chlorine / CYA Chart - Trouble Free Pool

 

[Nate4429]

Ok I’m just not sure it got lower as I have an auto feeder for bleach and it was more than half full at the time it dropped to 1...it is still working as I disconnected it to make sure it was still pumping out bleach...

 

[Msch99]

We had some near misses when we didnt swim or use the robot for a week or more. I think it was at least partially due to poor circulation allowing areas to drop below minimum. Even with the cover on, some tree droppings were getting into the pool which didnt help either. Now if we dont swim for a couple days we try to run robot to stir things up.

Once we identified what is generally the weakest area, we take our samples from there.

Even with an auto feeder I would check FC almost daily. Automatic equipment is nice but never trust it for extended periods. It doesnt know when you need more due to higher consumption for some reason.

 

[Nate4429]

I’m going to do the OCLT tonight. I’ll let you all know how it goes. Pool is crystal clear again! ??

 

[frogabog]

I love seeing how clear and pretty water becomes after a successful SLAM. Nicely done! Crossing fingers for your OCLT!

BTW, has it ever been quite that clear? Your first post only mentioned you seeing algae, not that you noticed it wasn't clear anymore. Just wondering...

 

[Nate4429]

Yes it was clear before this all started. I’ll post a pic from earlier this summer.

 

[Nate4429]

And yes the pool passed the OCLT! First try! ??

 

[Nate4429]

Now question...we throw a BBQ/pool party every weds evening from 5-9 and anywhere from 20-40 people of all ages (babies included) use the pool. Should I up my chlorine on that night? Give a boost right before or after?

 

[Msch99]

I boost beforehand if I can, 30 to 40 minutes. Afterward if things dont work out.

 

[frogabog]

Now question...we throw a BBQ/pool party every weds evening from 5-9 and anywhere from 20-40 people of all ages (babies included) use the pool. Should I up my chlorine on that night? Give a boost right before or after?

Oh! Thank you! If I leave by 1:30 I should be there in time. ;~}