Need a bit of guidance

[TMac0811]

So I've never posted to TFP before, but I wouldn't say I'm new because I've been a reader here for several years. I switched from pool store debauchery to liquid chlorine and the SLAM process so I've been a follower and a fan for a while. However I only just got my first Taylor K-2006 test kit this week.

I've SLAM'd before (with guess strips unfortunately) and usually I don't have issues.

This time seems like it's really taking a while, but that could be just in my head. When I opened my pool a couple of weeks ago it was green. About as green as it gets. Normally I SLAM, the algae dies and falls to the bottom while the water clarity is pretty fair, I vacuum, keep up the process and wind up with pretty clear water.

This time I think I'm on the right track but I'm just getting a bit worried I guess. I SLAMMED the green away to blue, but I've had foggy water for about 4 or 5 days now. I have been backwashing, and I've attempted to vacuum even though I haven't been able to see the bottom. We've brushed the walls, pool steps, etc. (Note that I've only just gotten a Taylor Test kit yesterday.)

I've only seen a slight improvement in water clarity, and even then the pessimist in me wants to think that's wishful thinking. The pool is blue, free of large algae blooms (tiny guys here and there), but it is persistent on being cloudy.

When I opened, my readings were basically zero. I adjusted (before I had my kit mind you) and got
FC: >10
PH: 7.5
TA: 50
TH: 0
CYA: 40

I've continued to SLAM, I took a reading for chlorine an hour ago and got:
FC: 8
CC: 0.4...?

(New to the K2006)

Should I stay the course? I do know from my reading here that testing PH right now is unreliable but it WAS in acceptable range. That being said, can I test anything else with my kit while SLAMming? CYA? TA? Would it even be necessary? Also I'm certain I did the CC test correctly but got a 0.4? Does this sound correct?

The only other details I can think to offer is that my sand filter should be okay because the filter itself and sand were replaced new last year. Any reason to think it needs to be opened and cleaned?

If anyone needs any other details I can offer them best I can.

30ft above ground vinyl pool.
21240gal
Hayward 1.5hp pump.
150lb sand filter

 

[mknauss]

Welcome to the forum!
Test your CYA with K2006.
Sand filters are slow to clear after a SLAM. Let us know the CYA and we can provide some additional guidance.
I suggest you read ABC's of Pool Water Chemistry.

 

[TMac0811]

Thanks for getting back quickly.

I tested CYA and it's between 40 and 50 on my vial, closer to 50ppm.

Just as a note I haven't added any stabilizer since starting my SLAM, and I'm only using liquid chlorine currently.

Also I forgot to mention that after getting an FC reading of 8, I added the calculator's recommended dosage of liquid chlorine to the pool to bring it back up to SLAM level. Will check it again in the morning.

Also also, it does appear that I'm losing less and less chlorine each day, but it's still pretty cloudy in there.

 

[mknauss]

I tested CYA and it's between 40 and 50 on my vial, closer to 50ppm.

Great. So use 50 ppm as your CYA.

When the water is blue and cloudy, and your FC loss is minimal, try Add DE to a Sand Filter - Trouble Free Pool

 

[TMac0811]

Seems pretty simple, thanks.

I think I've seen DE for pools on shelves, like maybe a Clorox brand. Is there anything specific to look for when buying or anything to stay away from?

 

[mknauss]

You must use DE for pools. When you add the DE, start slowly. And be ready to babysit the filter. It can plug quick to start. Backwash when pressure rises by 25%. You have to repeat after every backwash.

 

[TMac0811]

Just wanted to post an update on my progress to make sure I'm on the right track.

I've been maintaining slam levels of liquid chlorine for the past few days, and I am seeing the slightest clearing of my cloudy water, though I'd still call it cloudy.

I finally got a chance to add DE to my filter by following the directions here. I've never done this before, but I added 1/4 cup of DE at a time in a bucket of water, though I only did this twice before my initial pressure of 16 went up to about 17 or 18. It held right there, but I checked a bit ago and it had risen to about 20. It's only been about an hour or so.

Do I need to backwash it for a bit to bring that pressure back down? Would I not wind up starting all over and needing more DE? I'm just a little unclear on what is normal and abnormal with the process. I'm afraid if I backwash after only the short time the DE has been in my filter that I wouldn't get as much filtering help from it. I was at least hoping to let it run with the DE in it overnight before needing a backwash. Not sure if I'm making sense.

Also there is a small area in the center of the pool that needs vacuumimg. Should this obviously wait a day or two after I've run the filter with DE? I've vacuumed a couple times before the DE, though this is the first time I can actually see any of the bottom of the pool.

If pictures are needed or anything I can post them.

 

[mknauss]

Backwash when your filter pressure rises by 25% over clean pressure. Then you add DE again if you wish.

 

[TMac0811]

Hi, I wanted to follow up since it's been a few days and I think I might need a little bit more knowledge.

After running DE to help my sand filter and keeping up my SLAM, my pool has cleared up enough that I can see the bottom, BUT it still looks just the slightest bit off or dull to me. (Maybe my imagination.)

Pool clear, CC 0.0, and last night I passed an OCLT for a second straight night. (I checked both nights to make sure I wasn't crazy.)

I waited until my FC level drifted down to normal levels, but here are my test results from today:

FC: 5
CC: 0
PH: 7.4
TA: 90
CH: 40
CYA: 40

Should I give it one more day of SLAM or let the filter do the rest now?

Also I noticed my TA seems a bit on the threshold of being to high even though it's in the "ok" area. Do I attempt to tinker with TA or PH? The calculator says I would have to bring PH down first then adjust back up to fix this. I don't have much experience bouncing PH and TA other than to increase them when they fall too low. Is it worth adjusting or will my numbers be fine? I know I can find the info on what to do here I'm just wondering if I should or not.

I've attempted to attach a picture of my water, but storms are about to sweep over so apologies for the darkness.

 

[mknauss]

First criteria for a successful SLAM is crystal clear water. The look of the water around those steps in not crystal clear.

The pH and TA are fine. Just keep you pH in the 7's.

 

[IceShadow]

Check for hidden algae in things like the skimmer, steps, any folds in the liner, etc.

A deep clean of the sand filter might help, but if the sand was replaced a year ago, might not be the culprit. Note that new sand doesn’t filter as well as old sand, so that might be why you’re seeing an issue now where you didn’t before.

 

[TMac0811]

Thanks for the replies guys.

That was my suspicion that even though the water was clear, it wasn't quite crystal clear like I've had it before.

I've brought the pool to SLAM levels again and brushed some more areas of the pool again. There's still some vacuuming ahead of me, but already I've noticed the water getting even clearer than before.

What's better is I've gotten a real good hold of the new test kit because of this, and it's pretty incredible how accurately I'm adjusting the levels. This last SLAM addition of chlorine brought the FC to precisely where it needs to be.

I think I'll be fine now? Maybe? Undoubtedly I'll have more questions in the future but I guarantee I'm coming here.

Thanks to everyone here at TFP. Please keep doing what you're doing, you all are great at this and are helping a lot. And thanks again for every prompt reply.