Pool SLAM question

[morejp4]

First of all I'd like to thank everyone on here for such a really cool website that has already saved me a ton of money and allowed me to understand the chemistry of what is happening inside my pool. Thanks to all.

That being said, I am perplexed for the first time in the 2 years of owning my pool. We have a 20K plaster inground pool, College Station, Tx. Pool has an infloor cleaning system by AA that does pretty well except for a few corners that collect some sand and dirt. The spa overflow runs often as it is one of the "zones" on the infloor cleaner, and the water thus overflows from the spa down a rock river that connects it to the pool. I suspect it is this that causes my PH to drift up a bit, and I seem to have to add about a gallon of acid per week (in small doses) as well as adjust my TA up with baking soda occasionally. I also have an ozone system on the pool but I don't count on this thing to really do much other than just add a touch of insurance to things in case we lose track of things and forget to add some bleach. Typically, I have tried to keep the chlorine around 2 -3 PPM, and that takes usually around 1/3 gallon of 8.25% per day, more in the summer, less in winter. We don't shut down the pool in the winter as it is a major water "feature" right out the back door. Sorry, I ramble. I try to keep the water at the recommended trouble free settings, and I also use boron in the pool (Boric Acid) at 50 PPM. The pool is not salt, and generally gets pretty low use as it's just the 4 of us.

I travel (a LOT), and I do everything I can to try to keep things stable in the pool, but things do fluctuate a bit. Of course I know that everything is a moving target, but I really try to keep especially the PH and Chlorine spot on. I use the TF100 test kit weekly and check the PH/Chlor about every other day.

So, here is my issue. A few weeks ago we had a small pool party. The day before I checked things and our Chlorine had gone to zero. I had never seen this happen, but immediately brought it back up to about 4 or 5 (calculated, not tested). That same day I jumped in the pool and found some kind of slimy green stuff starting to grow on some rocks. I then brushed all the area that I could find. A few days later, I noticed the water just didn't seem to be as clear as I was used to. Short story long, I gradually moved to the process of slamming the pool. During this time, however, my combined chlorine initially was zero, but a few days later I got a reading of 0.5. That was when I started to do some more reading and realized I had a problem requiring to slam.

Now that I am in this process, my pool seems to just be devouring chlorine. I am trying to keep the Chlorine at 16+, but there have been periods where it has gotten down as low as 7 overnight, then I add it back up to the upper teens as quickly as I can. I am using liquid chlorine and going through about 2 or 3 gallons easily per day. The pool is crystal clear, but continues to eat chlorine. I am down to less than .5 CC now, but it is hard to discern the difference with the test, technically it is reading zero but the test sometimes has just a slight hue of pink to it with a single drop.

Here are the numbers that I am typically running with the pool, and my slam chlorine level I am trying to stay at 16+. I am giving these numbers as a range because that is the typical range they run in as I adjust the chemicals.

Typical
FC 3
CC 0
TC 3

PH 7.2 to 7.5

TA 80 to 100

CY 30

Borates 50

CH 275 to 300

Some other information. About a month ago I introduced 4 bottles of pro team "Metal Magic" remover as I thought perhaps I had some white scale on the plaster, but not sure that did anything except add some chemicals to the pool, could this perhaps added phosphates? A week after that I cleaned my Hayward 525 sq ft filter and found that the filter was pretty nasty, and had a bit of a funk to the smell. Lots of dirt, dead bugs, and some sand came out. I have since ordered new cartridges just in case, but hate to put those into the canister until I figure out what my current problem is. (If I have one??)

My chlorine loss overnight continues to be in excess of 5, but my pool is crystal clear, and CC is 0. I will continue to slam, and when I get home I will be cleaning the cartridge and checking all the rest of things for something wrong (maybe I sucked a dead animal in the floor cleaner and it' stuck in there or something, or there is some nastyness that needs to come out of those filters).

Anyway, how long is this going to take (Almost a week now), and is there a chance I screwed up with the Metal Magic and phosphates or something?? I am at a loss. never had any issues before, would love to hear from ya'll.

BTW, my local Walmart just started selling liquid chlorine at 10% in the pool section, $3.96 a gallon normally, but last week it was on rollback to $2.50. I'm gonna buy all I can store. Also, my next pool upgrade is going to be the (CHEM) system to monitor my pH and ORP through the Omnilogic panel, and I'm gonna try to use a pump to feed liquid chlorine automatically and a CO2 system to control the PH. That's gonna be another thread.

Thanks,
Mark

 

[Casey]

Welcome.

Sounds like your FC dropped enough for the green monster to get a foot hold in the pool. Your target FC level for your CYA level of 30 is 4ppm. You've dipped below that and have the green slime. You're losing FC at night so you're consuming something. Honestly, no one can tell you how long this will take but I would encourage you to keep on the SLAM and brush the pool til your arms fall off.

 

[pooldv]

The first sign of algae in the pool is unexplained chlorine consumption, then slimy walls, then cloudy water and then green water. I had algae last summer and the water was clear and CC was 0. Time to SLAM the pool.

Phosphates are not important. That is pool store baloney to sell you something.

 

[morejp4]

All,

More information. As I said I travel a LOT. But my wife attempts to manage everything including the pool when I'm gone. She is a microbiologist, but she hasn't read any of the info on here. Other interests for her.

Anyway. Came home this morning and she has been brushing the pool, but now there is some blackish mold growing on the rocks down the river. So, since I was gonna rent a pressure washer for some other stuff, I ran out and rented one this morning and I'm in the process of trying to knock some of that stuff off the river and other rocks around the pool. I will try to collect all I can without it going into the filter, but will continue to slam this thing hard till I see proper progress. I will clean the cartridges tomorrow after what I wash off the pool today has time to find it's way to the filter. This river thing may prove to be a problem, as the water only run's down the thing 1 out of 5 or 6 other zones, so it does not get a constant flow of clorinated water. I can turn on another pump and make that happen for a while, though. But the growth is above the water line for the most part. Noticing some greenish stuff in other places on rocks above the water line. I'll see if the pressure washer can help me get ahead of this stuff, then bleach and scrub it to death for as long as it takes.

I'm gonna try to take some pictures of this stuff, before and after the pressure wash, and I'll post them later today when I get a chance. Gotta get this pressure washer back in 4 hours ;-). And yes, I will be careful about not hurting things with the pressure washer. Main reason for the pressure washer is a different project, so I didn't rent it just for the algae.

Casey.... Thanks for the response that confirms what I have never dealt with before. Not looking forward to my arms falling off. I have a 15 year old daughter, though ;-)
Pooldv... Same thanks to you. And thanks for confirming the phosphate thing. In the back of my mind I was a tad worried I had got some fertilizer in the pool from the yard, but I was really being pretty careful about it.

Wondering if Richard the Chem Geek could some time perhaps explain the chemistry of the stuff they try to sell in these stores to the rest of us. They often have NO information on their labels. I am not a chemist but it would be interesting to get a better insight into what is in those bottles.

Off to work...

This is really sealing my case that I need to have a more consistent way to automate the addition of chlorine to the pool with a liquid feeder. I don't mind working on things when I'm home and setting it up, as this seems much less likely to happen in the future if something is watching the pool when I'm away.

 

[RobbieH]

SLAM can take weeks in some cases. A friend of mine battled it for three full weeks before he cleared the OCLT. Watch for hidden algae in nooks and crannies, behind lights, etc. They can be the culprit.

With a TA of 80-100, why are you still trying to drive it even higher?

 

[morejp4]

With a TA of 80-100, why are you still trying to drive it even higher?

Robbie,

Good question... The TFT100 instructions recommend 100 to 120 I think for a chlorine pool. Poolmath says 70 to 90+. Back in the wintertime I wasn't paying attention and it got down around 40, so I've been under the impression with my river "aerating" things I needed to keep the TA from drifting down. 80 seems like a good range??? What would be the advantage of keeping it down lower? I'm considering switching to a CO2 bottle for PH lowering and one of the advantages to me would be that the TA won't drift down as much. Love your thoughts on that one too.

Thanks,
Mark

BTW... 4000 PSI pressure washer when aimed into rock crevices or a pool can have surprising kickback in terms of wetness. I had a lot more moss/algae/black junk than I had originally seen. Just dumped 2 more gallons of bleach straight onto the rock river and that was pretty interesting. Killed some stuff for sure. I'm gonna mix up a garden sprayer with some 20% bleach for that purpose over the next week or so as I continue to slam. Off to buy more chlorine.

 

[morejp4]

Update.

Didn't touch the pool at all today, as I planned on cleaning the filters and some other stuff, BUT, with the 10 inches of rain we received today I couldn't even walk out there, except to blindly add in 2 more gallons of bleach. I figured at the rate the pool had been eating chlorine, wouldn't be an issue of risking going too high. However, tonight I measured the FC at 28 with no CC. Yikes! I had also run the rock waterfall all last night to maximize the circulation, and that has my ph up at 7.8. With the fact we could easily get another 2 or 3 inches of rain tonight, and the pool has been overflowing at least 8 inches today, I'd rule out an overnight loss test as valid.

Since it was raining all day and I was close to town, I stopped in and purchased a 50 LB CO2 bottle from a local welding shop. So you know, the 50 pounds is what is inside. The bottle itself weighs WAY more than that. I'm pretty stout and I had to manhandle the tank out of my truck onto a cart to get it to the shed. The bottle cost me around $330, and I will be able to refill or exchange it for about 25 dollars. I still need to order the rest of the parts I will need for that whole setup. CO2 Solenoid/valve and check valve/injector, Hayward Chem system with PH and ORP probes, and I'm thinking a Rolachem 32 GPD (maximum) pump for the Chlorine feed. I've got a 6 gallon container I can use for a Chlorine tank that fits perfectly inside a chlorine locker I built that is OUTSIDE my pool shed. I don't like keeping chemicals in my shed at all, as they off gas and corrode anything near them. It has become obvious that I need a bottle cart or at least a hand cart to manage the CO2 tanks. And I think a bottle saddle with some rollers in my truck would serve to slide the tank in and out of my truck. Gotta think like Rube Goldberg all the time... Hypercomplicate at any opportunity.

Here is a shot of that blackish stuff on some rocks. It is all blasted off now and gone from the pressure washer.



This shot so you can see my "river" from the spa to the pool. The water is really blue because the LED light is blue. But my water is pretty clear.

 

[morejp4]

Ok,

It's been basically 2 weeks of Slam. I have learned a lot from this process. Most importantly, I will NEVER let the chlorine level drop like that again and will do a better job of watching things. Secondly, I was in disbelief day after day when my chlorine levels would be dramatically lower than I expected.

Yesterday it was warm enough to jump in the pool and remove my 3 light covers, from what I had read on here a likely harbor of slime. Other than some dirt back there, no algae. Cleaned them anyway, brought the chlorine up to 19, scrubbed the **** out of every nook and crany I could find. Then spent the night researching cleaning robots because I really don't like brushing the pool. I find it's a lot of work for very little horsepower applied to the actual surface. I think I have become overly reliant on our infloor cleaner to do things and we have become VERY lax about brushing, even during the slam process. The robot would be better than our lax brushing.

Also, threw the breaker on my Ozone generator. I was wondering if this thing has been eating some of my chlorine?? I have heard conflicting reports and wonder if the thing has done anything other than lull us into thinking we were better protected that we were. It did not run last night, only the main filter pump and the floor cleaner. Heck I don't even know how to tell if it's running. It's an AA system that has a VERY faint blue light on the front. Had to squint and turn the shed lights off to even see if I had popped the correct breaker to kill it.

So, this morning, I am happy to report the FC holding at 19 with no CC. Water appears very clear. No smell despite high FC. I will check it again tonight after a sunny day. I have added some stabilizer, as with the 20 inches of rain we have had during this process mine was down to CYA 20. I'll try to get it back into the 30 range and go from there.

Here are the latest numbers. Not exact but pretty close, as I don't have time to run them exactly till tomorrow morning.

FC 19
CC 0

TA 80
CH 225
CYA 30 (calculated after adding 2 pounds just now from a CYA of 20)

Borates 40 (estimated after the big rain, I'll have to make a guess with that based on those borate strips that are almost as good as guessing)

PH 7.2 (probably not exact as I understand the high FC messes with the test, but I will keep an eye on this one as always)

Anybody that can comment on the ozone eating chlorine??
Anybody else that can hope with me that this thing is done??

I'm in the process of getting ready to automate the chlorine with the Hayward Sense/Dispense through my OmniLogic panel. I'll be running a RolaChem 12 GPD pump on that, and CO2 bottle to feed carbonic acid. I'll start another thread on that when I get the parts headed my way...

Cheers to all. And BTW, the pool was awesome yesterday after the first few minutes. 84 degrees.
Mark

 

[pooldv]

It is a common misconception that high chlorine levels in a pool leads to the "chlorine" smell. Actually, CC is what people smell when they smell "chlorine" in a public pool. And low chlorine levels make that worse because it takes chlorine to burn off CC.

LOL at your comment about only SLAMing once! I think most folks only SLAM once. Except me! I got overconfident/lazy last summer and had to do a little SLAM. That is also when I stopped being VERY LAX about brushing. :-D

Everything looks good! Congrats on the good

More about ozone here, Alternative sanitizers and pools--The Truth!!

 

[morejp4]

Pooldv,

I didn't mean to indicate that I should be able to smell the chlorine, but rather the lack of it. As while I was slamming the pool I would occasionally get a whiff of chlorine smell and around the pool sometimes things smelled a bit "earthy". I haven't had that smell in the last few days, which I'm hoping coincides with the CC staying at 0.

Last night the chlorine held again at 0 loss and 0 CC. So I'm pretty sure the pool is fixed. It's raining again this morning, and the whole system will have produced almost 25 inches of rainfall within the last week or so. Forecast to get more over the next few days. Say a prayer for all those downstream in Texas dealing with much bigger problems.

You mentioned overconfidence and being lazy. I dido that... It's what got me to this experience. I think the infloor cleaner is great, but now realize the limitations. Didn't know and had never really thought about "biofilms" and creepy stuff like that. I'll probably end up getting a motorized robot to throw in there a few times a week. That plus automation of the ORP and PH hopefully will go a long ways towards not having this happen again.

I'm headed out to the shed right now to install electrical boxes that will tie into the Omnilogic relays and dispense things. Hopefully I won't get zapped too bad ;-)

 

[kcindc]

Glad that you passed the OCLT. Might want to bring your TA down a little since a high TA+aeration=increase in PH. The purpose of TA is to stabilize PH. If your PH is constantly increasing, you should work on getting your TA down. Each pool is different so you will have some trial and error to find the balance your pool needs.

I just bought a robot a few weeks ago to replace my Polaris and I love it! It doesn't remove the need to brush, but I'm hoping it will help me out when I'm little lax or when my work schedule is insanely busy.

I'm sure others would love photos of your new setup.

 

[morejp4]

kcindc,

Thanks for the advice on the TA, seems to mirror what others are indicating on here about the same. I will just let it drift down and play with things to see how it reacts. During the slam process I have been keeping better records of things than normal. I am noticing that my ph drifts up about .1 per day. Maybe slightly more. I think in general I have tried to keep my ph a little lower than most at 7.2, and not sure there is a valid reason for that. Might save me some chems and effort if I let it drift up into the mid 7's. I'll play with that as well. Haven't added any bleach in about 3 days now, and the FC last night and this morning was sitting at 6.5 with no CC.

As for the pictures. I would post all kinds of them, but I keep getting a message about exceeding my quota for space. I need to mess around and see how to resolve that. Even tried shrinking some pics down in size and still got the same message.

What kind of robot did you get? And what are you seeing as far as wall climbing ability? I am seeing prices from 500 to 1500 dollars on these things, but if I'm gonna spend the extra coin it better be a climber and an eater.

Cheers.
Mark

 

[kcindc]

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I got the Dolphin Triton Plus with remote and caddy. It climbs the walls and the first few steps, but it seems a little inconsistent on scrubbing the tiles. Top cleaning and two types of filter options (spring clean for big stuff and plated for finer particles). Not sure how smart it is, but it does a great job.