Preparing to SLAM (maybe?)

[tjhannan]

Hi all! Love this forum. I've seen a few posts similar to this one I'm starting but none are quite like mine so I'm starting a new one. My pressure in the filter housing will not stay down. I cleaned the carts (Pentair CCP420) last week and the pressure was down for a few hours, then went back up (from 15 psi to 28 psi) over 4 hours. Then I soaked them with dishwasher detergent for several hours. Pressure went from 14 to 28 but it took 5 days this time. Now I'm thinking I have an algae problem, but I don't see any algae in the water or filters (filters are only 3 years old). Water is clear. Pool is in ground (35,000 gal) and covered when not being used. Will be doing a OCLT tonight. Is there something besides algae that could be causing the pressure drops? Also, when I use the TFP SLAM calculator, with a CYA of 50 my SLAM level is 20. What does that mean? Current levels are:
pH-7.2
TA - 120 (been working on bringing this down with MA and aeration to help bring the pH back up naturally)
CH - 375
CYA - 50
FC - 5.5
TC - 6.5
Any tips for SLAMing out there or maybe I don't have to? Thanks for your help!

 

[Texas Splash]

Welcome to TFP! Yes, with a CYA of 50 your SLAM FC level will be 20 as noted on the FC/CYA Levels. That means that during the SLAM Process you want to try and maintain that elevated FC level as best as you can until you pass all 3 SLAM criteria.

Doing an Overnight Chlorine Loss Test is a good choice. If you fail the OCLT, then you know the SLAM is next. Follow the SLAM Process page carefully and you should do fine. Let us know if you have any questions.

Also see ------> Pool Care Basics

 

[tjhannan]

Couple of follow ups:
1. should I keep my pool cover closed during the SLAM?
2. Ball park number of days this process can take?

 

[PoolStored]

Couple of follow ups:
1. should I keep my pool cover closed during the SLAM?

I'd leave it open.

2. Ball park number of days this process can take?

Every pool is different. Best way to give you any sense for you to post pictures of the pool water. A wide shot and one looking down into the water.

 

[tjhannan]

Just did my OCLT and FC only dropped 0.5 ppm - from 2.5 to 2. Now I’m wondering if my filters are clogged with something else? Will soaking them in MA and water mixture possibly solve my problem without a SLAM?

 

[PoolStored]

With a CC of 1, a slam is in order, even if your FC loss was <1.

SLAM ON!

 

[tjhannan]

Here are som pics this morning. Deep end is 9 feet and the drains at the bottom are clearly visible.

 

[PoolStored]

With that visual and CC = 1, Start the SLAM.

 

[tjhannan]

With that visual and CC = 1, Start

I'd leave it open.

Every pool is different. Best way to give you any sense for you to post pictures of the pool water. A wide shot and one looking down into the water.

Why leave it open? Won’t that make it harder to maintain SLAM levels?

 

[PoolStored]

Why leave it open? Won’t that make it harder to maintain SLAM levels?

Not enough to make a big difference. You have CC, having it open will help get rid of the CC.

 

[tjhannan]

Not enough to make a big difference. You have CC, having it open will help get rid of the CC.

Thanks again. Started the SLAM and have FC levels at a 20. With the clear water, and pH of 7.2, is it safe to swim during the SLAM? If so, does that make it more difficult to maintain SLAM levels?

 

[PoolStored]

With the clear water, and pH of 7.2, is it safe to swim during the SLAM?

Yes if you can see that bottom.

If so, does that make it more difficult to maintain SLAM levels?

Only marginally. Enjoy the swim.

 

[tjhannan]

Better pic of the pool now that it’s in full sun…hard to believe it needed a SLAM when it looks like this but chemistry is chemistry.

 

[PoolStored]

Looks better already. Please don't diver from there...

 

[tjhannan]

Day 5 of SLAM. OCLT results look like this:
Night 1 - 19.5 to 15
Night 2 - 23 to 19.5
Night 3 - 21.5 to 21
Night 4 - 20.5 to 18
Pool is clear. Filters look clean. Pressure in the filter house still creeps up over time (only other indication that something is going on). I didn’t trust my night 3 results because I added some liquid chlorine about an hour before my last test of the night and I wanted to be sure that it wasn’t an error. Night 4 saw a drop of 2.5. Crossing my fingers that I don’t see much of a drop tonight because I’m starting to feel like I’m wasting my time and money.

Question - I’m usually at or above FC of 20 but it will dip below from time to time and I bring it right back up again. Is it better to keep FC 2-5 ppm above SLAM levels to avoid dipping below the 20 or is the occasional drop ok?
Pic of day 5, 4:00 pm

 

[PoolStored]

Did you remove the main drain covers and scrub underneath? If not, do it.
Do you have a light and did you remove it and scrub behind it? If not, do it.

Your target is 20. Test. Add enough to get back to 20. Wait, test. Rinse and repeat. No need to go higher.

 

[tjhannan]

Did you remove the main drain covers and scrub underneath? If not, do it.
Do you have a light and did you remove it and scrub behind it? If not, do it.

Your target is 20. Test. Add enough to get back to 20. Wait, test. Rinse and repeat. No need to go higher.

I have four small puck LED lights…1 1/2” diameter? Not even sure how to remove them but I’ll try that next.

Haven’t removed the main drain covers. Thanks for the tip!

 

[tjhannan]

Removed main drain covers. Looked clean as ever but I scrubbed them anyway as well as the drain piping below them. Never saw anything that looked like algae. Still don’t know how to remove my LED lights… anyone have lights that look like this?