First time SLAM - FC levels WAY high after first bleach add?

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Re: First time SLAM - FC levels WAY high after first bleach

So I calculated that the turnover rate for our pool is just over 2 hours. (5460 gallons per hour). The pump/filter are probably just 5 feet from the pool, so I should be getting maximum flow. I've read on here that you want to have 1 turnover per day. Does that mean I only need to run it for 2-3 hours a day?? Seems like not much. I've set my timer right now to run for 5 hrs per day. Does that sound more reasonable? I think if the pump ever goes out, i'll get a 3/4 hp 2-speed pump maybe and just run it all the time on the low speed. But i suppose I should just use what I have for now, but just run it less.
 
Re: First time SLAM - FC levels WAY high after first bleach

I highly doubt that you're getting anywhere near 91 gpm. That 150 lb sand filter will provide a lot of head loss in that system.
What model pump do you have?
I assume that you have 1 skimmer and 1 return?
What size eyeball is in the return?
What is your filter pressure?

I suspect that you're getting about 35 gpm or less.

Having said all that, it really isn't important. Run the pump long enough to keep the pool clear and chlorinated. It doesn't really matter how many turn overs that is.
 
Re: First time SLAM - FC levels WAY high after first bleach

Updated the signature, but its a Hayward PowerFlo Matrix. The filter pressure is 15 psi when clean. It is 1 skimmer and 1 return. All hoses/fittings are 1.5", but not sure what size the eyeball is. Its the one that came with the skimmer kit, which is Hayward SP1091WM. All i know is when its 15psi (clean) the return is putting out a very forceful stream. Maybe i'll run with 5 hours for now and see how it goes....
 
Re: First time SLAM - FC levels WAY high after first bleach

So I think I could use a little more advice. We SLAMed and had the water crystal clear 12 days ago, and we stopped the SLAM after we passed all 3 of the SLAM tests. About 4 days ago I noticed greenish/brownish spots developing on the bottom of the pool(pic below), which i vacuumed up. They came back the next day, followed by the water getting a little cloudy. So I guess the only thing it could be is algae. So I'm trying to figure out what I'm doing wrong. Isnt that early to be having algae issues after SLAMing? Here are our levels:

Total Alkalinity: 90
CYA: 30-35ish (was a little higher, but we've backwashed several times and had to add water)
PH: 7.5
CC: 0
FC: We've used a target of 4.5. When we've checked it (in the morning) for the last 12 days, its usually been somewhere between 1 and 4 (lately closer to the 1-2 ppm) so each day we add enough bleach to bring it back up to 4.5. A couple evenings I've tested and made sure it was 4.5, just to be sure the amount we were putting in is enough.

We were running the pump 24 hrs a day, but a couple days after the SLAM (when the water seemed 100% clear) we took it down to 6 hrs/day. We have a 1.5 HP pump, which is overkill, so I figured I'd try to save some on electricity, since that should be more than enough for a turnover + some. I have the pump running from 9-11am (we check levels and add bleach at 9am), and then again from 4-8pm.

So does anyone have any advice? Is it normal to need to SLAM this much? Am I just not running the pump enough or maybe need to raise the CYA levels some to keep the chlorine more active during the day? You can see the algae spots below. I also swam down and looked on the inside of our cake-style stairs in the pool, and theres a good amount of algae growing on the lip on the inside, and even on the sand-filled bleach bottles I have holding the stairs in place. Thoughts anyone?
 

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Re: First time SLAM - FC levels WAY high after first bleach

leashy333 said:
FC: We've used a target of 4.5. When we've checked it (in the morning) for the last 12 days, its usually been somewhere between 1 and 4 (lately closer to the 1-2 ppm) so each day we add enough bleach to bring it back up to 4.5. A couple evenings I've tested and made sure it was 4.5, just to be sure the amount we were putting in is enough.
Click to expand...
This right here is part of the problem. While 4 is the "target", 2 is the minimum. Anytime you let FC get below 2, you're letting algae regain a foothold. Don't ever let it get below 2, and you probably want to "target" 5 or 6 to give yourself a buffer for when it falls.
 
Re: First time SLAM - FC levels WAY high after first bleach

I think this happens often. They use the "target number" as if it were etched in stone. A lot of times that's not enough wiggle room for chlorine drop during the day.

I always go above my "target" to allow for FC drop so I don't fall below min levels. Especially if the water temp is fairly high, or the pool is seeing a lot of use.

Just my 0.02.
 
Re: First time SLAM - FC levels WAY high after first bleach

Excellent. Thanks for the advice. I'm still learning, and love this site! Guess I didnt realize how much of a foothold the algae could get if the levels fell a little below target minimum. So far no one has said anything about the pump runtime, so i guess that is probably ok?
 
Re: First time SLAM - FC levels WAY high after first bleach

Yes, it appears you need to do the SLAM process again since you allowed your FC to drop too low.

leashy333 said:
So far no one has said anything about the pump runtime, so i guess that is probably ok?
Click to expand...
After you finish the SLAM process this time, you can probably back down to less than 6 hours run time. Take a look at this pool school article: http://www.troublefreepool.com/pool-school/pump_run_time
 
Re: First time SLAM - FC levels WAY high after first bleach

So i started the SLAM yesterday morning. I've been going a little higher on the FC (targeting 15) just to be sure. The water last night before going to bed was crystal clear from what I could tell (been adding DE to the filter to help w/ filtering, had to backwash 3 times yesterday). The overnight FC drop was from 15 to 13, so need to keep SLAMing. One question - I'm still getting spots on the bottom of the pool like you can see a few posts up. Its getting less now, but they're still appearing. I swam down and looked at them the other day and I am about 95% sure they are algae spots on the pool liner - they're greenish in color. Should I still be getting these even while I'm SLAMing? I vacuumed twice yesterday, in the morning and before bed, and this morning I still have some spots. Like I said, its far less than before, but they're still appearing, which seems to me that would mean algae is still growing in a FC-15, CYA-30ish pool?
 

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Re: First time SLAM - FC levels WAY high after first bleach

leashy333 said:
I swam down and looked at them the other day and I am about 95% sure they are algae spots on the pool liner - they're greenish in color. Should I still be getting these even while I'm SLAMing?
Click to expand...
Do the spots brush off? Are they located generally in shaded areas of the pool/pool sides? Something organic is still being worked on in your pool by the chlorine since your OCLT was greater than 1.
 
Re: First time SLAM - FC levels WAY high after first bleach

Yeah they brush off easily. And they vacuum up fine - I've been vacuuming them up since I figured that'd be better than just brushing them and mixing the stuff up w/ the water. I wouldnt say they are located in shaded areas, really kind of all over. But now that I think about it, more spots show up around the edges and about 1-2 ft out, and not many of them have been in the middle. There have been none on the walls. Its just on the bottom. I definitely agree its something organic. I'm just surprised they're still "growing" or "forming" or whatever when the chlorine is beyond shock level for the cya.
 
Re: First time SLAM - FC levels WAY high after first bleach

Ok, so the algae is coming back again, with algae spots on the pool floor and water getting a little cloudy. This time I know for sure that our FC has been high enough. According to the Chlorine/CYA chart on here, the target FC for 30CYA is 4. I've set my target at 6 and have checked the pool daily. Usually its around 4ppm when I check it in the late afternoon, so i add enough bleach to bring it back to 6.

A couple more details:
1. According to user "linen", he said I could probably run the pump even less than the 6 hrs I was running it last time when I started getting an algae issue. So after I SLAMed the last time (on Sept 4th-5th), I got the pool crystal clear and then turned the pump run time down to about 4.5 hrs/day.
2. This is a long story that you can read about on another thread, but I've had spring water from under our house dumping into the pool every several hrs, about 7 gallons each dump. I've just left it dumping most of the time, in order to just keep the level of the pool up from evaporation/backwashes, and not have to add any water with the hose. I have a duda-diesel filter (as suggested by another user) thats filtering the water from under the house, and there are a couple real small green algae spots on the filter bag (filter is hanging over side of pool but not actually in the water), so theres a chance a little algae is making it into the water from there, but it seems like keeping the FC at 6 should kill it enough to not have an algae issue right?
3. I've vacuumed about twice a week. It started as just vacuuming dirt/leaves, but since Thursday/Friday (about 1 week after the last SLAM) I've had to start vacuuming the algae spots up.

Anyone have any ideas why I keep having this algae issue? Both times I SLAMed I followed the process to make sure I met the 3 requirements for stopping the SLAM (water has to be crystal clear, pass the overnight OCLT test, and have CC less than .5 ppm). Both SLAMs we've done, after 2 nights of SLAMing, we passed the 3 tests. And this last SLAM, I set the target FC 2-3 ppm above the target FC shock level, just to be sure.
The only other thing I can think of is maybe the pump isnt running enough? But according to "linen" and the link about pump run time he posted (from pool school), apparently it really only needs to run enough to mix the chlorine in good, and any more than that is up to your preference on how clean you want the water to be from debris.

Another question - following BBB/SLAM methods meticulously like I have, how often would you expect to need to SLAM? And how long should a typical SLAM take?

I know I still have a lot to learn, but I really want a trouble free pool and want to figure out how to eliminate this algae issue :)
 
Re: First time SLAM - FC levels WAY high after first bleach

You can try pointing one of our returns diagonally downward to improve bottom circulation. If you have vacuumed up some of the material, can you capture it and see if it is slimy like algae vs. squishy like pollen? Do you have any trees in your area that could be dropping pollen into the pool? Do you notice any pollen on the surface of the water?
 
Re: First time SLAM - FC levels WAY high after first bleach

Its more slimy like algae. Havnt seen anything floating in the water. And the bottom of the pool has been a bit slimy feeling the last few days when I've got in. Whatever it is, it doesnt seem to be collecting on the bottom, but rather growing on the bottom. When i vacuum the pool, I usually miss a few spots, which means the water moving around near it when I vacuumed wasnt enough to disrupt it, b\c its stuck to the bottom and not just settled there.

I suppose I could try pointing the return down more. Its angled down slightly, but not a lot. Something I just thought of by your suggestion - maybe I should try to collect a water sample from the bottom and one from the top and compare the FC level of the two and see if there is any difference.
 
Re: First time SLAM - FC levels WAY high after first bleach

leashy333 said:
Something I just thought of by your suggestion - maybe I should try to collect a water sample from the bottom and one from the top and compare the FC level of the two and see if there is any difference.
Click to expand...
That's tricky to do, but would be helpful. You have to collect the sample in a way where you aren't mixing the water. If you are in the pool trying to do this, it will be next to impossible. You'd need a tool where you can carry the tube upside down and slowly move it to the bottom before inverting it upward (preferably capping it) and then bringing it up. Perhaps an easier way is to slowly lower a rubber hose to the bottom keeping the other end capped to keep air in it, then release the cap to fill the tube with water from the bottom, then recap the end and pull out the hose to get your sample.

If the bottom feels slimy, it's very doubtful it's getting enough chlorine. I presume that with the earlier SLAM you brushed the pool as instructed. Otherwise, you don't get rid of biofilms on surfaces since they are chlorine-resistant.
 
Re: First time SLAM - FC levels WAY high after first bleach

Yeah I brushed and vacuumed a couple times during the SLAM. Bottom is not perfectly smooth, so definitely a possibility some indentions were missed.
 
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