Need help with Green water

cmnet

0
Feb 3, 2014
22
Baton Rouge, LA
New to the forum here. I have a 15x36' gunite saltwater pool. Runs on a Pentair Whisperflow pump with 4 cartridge filters. I'm struggling with regaining my clear blue water.

A couple weeks ago it began to turn green. Not cloudy but a clear green. Water temp is 52 so I found that surprising. My Pentair intellichlor was no longer producing chlorine, and the reading from the Taylor test kit was clear without a hint of pink, .5-1 range.

A week prior to that, I had some brown stains that I treated with Ascorbic acid (with the chlorine nearly at 0), followed by 32 oz. of Metal-Free. The standard AA treatment. Did help but not fully eliminate the stains.

Here is what I have done in the past week: 5 days ago added another 32 oz. of Metal Free at the advice of local Leslie's employee, ran pump for 24 straight hours, then thoroughly cleaned filters (pressure now at 10, was at 20 when dirty). Then put chlorine tab in skimmer to slowly raise the levels.

After waiting 4 days for the water to clear up, yesterday I became inpatient when seeing chlorine still at .5-1 and still green (but no algae stains) and put 4 lbs of granulated chlorine directly into the pool. Result? Now obviously a 5-10 chlorine reading, but water is now GREENER than before.

What should I do next? Any help is greatly appreciated! Total alkalinity is 90 (raised last week from 60), calcium hardness 290 and pH is 7.2, and I have not let it get above 8 or below 7 this entire time.
 
:wave: Welcome to TFP!!!

Given the low FC level, you could have some algae growing, but sounds more like metals in the water turning it green. When you add chlorine, that can trigger the green to show up. Sounds like you need more sequestrant in the water. Here is an article in Pool School you should read: http://www.troublefreepool.com/content/137-metals-in-the-water-and-metal-stains

Couple other notes:
- We never recommend putting pucks in the skimmer ... can be bad for the equipment.
- You need to be careful with using granular chlorine as it may increase your CH or CYA up out of the recommended levels ... stick with using liquid chlorine (bleach) to maintain the FC while the water is too cold for the SWG.
- The SWG might be functioning, but not able to produce enough FC fast enough to overcome a possible low level algae growth. You could do the OCLT to be sure: http://www.troublefreepool.com/content/136-perform-the-overnight-fc-chlorine-loss-test-oclt
- Do you have one of the test kits with the FAS-DPD chlorine test? Which Taylor kit do you have?
- You did not report your CYA level, which makes me suspect you do not have the recommended K-2006 (or better yet the TF-100) test kit.
 
I have the k-2005 kit. Just did the CYA test and the black dot never "disappeared" even when I reached the top of the comparator where the reading is 30. I did put 32 oz. of Metal Free in just last week, and had already put 32 oz in a couple weeks prior to that as part of asorbic acid treatment. So I should put some more in? It's a 16k gallon pool. Any product suggestions besides the expensive ($30) Metal Free 32 oz container? I've been running pump only 5 hours a day since the water temp dropped below 60 in December, 10 hours a day until then.

Alos, my pool builder suggested just "nuking" the pool with at least 5 and preferably 10 lbs of shock, since no one is swimming in it right now anyway. I told him I'd just dropped 4 lbs of chlorine in which made it even greener, but he explained that plain granulated chlorine does not have the extra ingredients that shock does. But I'm checking with this forum first. Thanks!
 
Did you read the links I provided? They list some of the sequestrants we recommend (actually Metal Free is not the type we recommend). I have no experience with how much you will need.

With a CYA that low no wonder your SWG can not maintain a FC level, the sun is likely destroying the FC as fast as the SWG is making it.

Your pool builder does not know what he is talking about. They build pools and generally seem to have no idea how to maintain the chemistry.

Please read Pool School to learn the chemistry and the levels we recommend. Start with these:
ABCs of Water Chemistry
Recommended Pool Chemicals
How to Chlorinate Your Pool
Water Balance for SWGs

BTW, you should order the FAS-DPD chlorine test to supplement your kit and give you the equivalent to the K-2006: FAS-DPD Chlorine Test
 
It turned green due to not enough sequestrant and adding a lot of FC all at once.

Continue to maintain the FC level with bleach until the water warms back up and the SWG can work ... for now I would get the CYA up to around 40ppm. Then when it warms up, raise it to around 70ppm to help the SWG.
 
I just added 64 oz of Metal Magic, and running the pump overnight. Rain coming down so I double checked the pH (still 7.2) and Chlorine (5+) beforehand. Depending on how much rain we get, that could be different in the morning. I expect to clean the filters tomorrow. Pump Pressure is at 14 now, usually at 8-10 when thoroughly clean. At that point I'll run the pump all day and cross my fingers that it won't be the greenish-brown color I see right now.
 
As said before I don't think that is one of the recommended sequestrants.

We recommend cleaning the filter when the pressure rises 20-25% over the clean pressure. You are way past that.
 

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Ah, I thought you used the same stuff you mentioned earlier, metal free ... oops.

And if your pressure has gone up nearly 50% then it is certainly dirtier than we recommend letting it get.
 
I'd planned on cleaning the filter this afternoon after the Metal Magic had some time to work, but I'll do it this morning instead. Water still as green-brown as yesterday, though. Does it make sense to raise CYA with the water this green-brown color? To recap, FC is still sky high due to 4 lbs of granulated chlorine 2 days ago. This made the green color even worse, so I added 64 oz. of Metal Magic approx. 14 hours ago. Besides cleaning my filter, I'm wondering what to do next? Off work today so I have all day to do what it takes to get rid of this green

- - - Updated - - -

Oh, another issue I'm noticing, probably not relevant to the green water, but my SWG is showing a low salt reading even though water temp is 52. I have the output set to 20%, vs. 60-80% during summer. Last year when it got below 55 it showed "Cold Water - System off". Its a Pentair ic40 Intellichlor. Cleaned in October at season's end and noticed no build up then, but Pool Store guy says the sensor is probably off and I should have it serviced in May before water warms up.
 
Well the filters are bright white again, back to 9 on the pressure gauge. pH is 7.2, FC still near 10, CYA under 30, TA 80. I suppose its time to let the sequestrant and chlorine do their work. I do think it looks better than yesterday at this time. Not as murky.
 
You should ideally continue to clean the filters whenever your pressure gets up to 11psi.

I am not sure how long it is supposed to take for a sequestrant to work. Is the water still clear, but tinted?
 
Yes, it's not a cloudy green at all. Sun is out now so its easier to see. I'll keep an eye on the filter pressure. There was hardly any grit in the filters, simply a tan coloring that came off easy with a hose. I'm planning on running the pump all night again.
 
Well folks I am about ready to throw in the towel and call a cleaning service. Water still green. Filter pressure at 10 (up from 9 following cleaning yesterday). FC and TC are equal. Both are over 10ppm so the levels are not lowering from Monday's 4 lb. chlorine dump. pH is 7.2, TA 80 and CH 280. CYA is less than 30 (black dot on Taylor test still visible at 30). I've done the Metal Magic, and am wondering at this point why not hit it with 5 lbs. of shock? 5 gallons of straight bleach perhaps? OR call someone.
 

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