green then clear then teal

[Crashedmatrix]

I have a UG with a sand filter. Last month the pool was green and I followed the SLAM technique and after a couple weeks the pool was completely clear and passed the overnight test. The last two weeks the pool has been clear and I have been maintaining balance. Last weekend after a few days of rain I noticed "dirt" on the bottom of my pool so I tried to vacuum it to waste. The vacuum was having a difficult time getting the "dirt" off the bottom without scrubbing. While scrubbing the "dirt" started to puff up off the bottom. I decided to sweep the walls and floor to get it all cleaned up, hoping to vacuum it all again the next day. When I finished sweeping the pool it turned cloudy and the next day the pool was teal. The filter seems like it takes forever to clear the water some of the reason I think it took so long for the pool to turn clear the last time it was green. I passed the OCLT way before the pool was completely clear, but I kept SLAMing until it was crystal clear. It didn't require much LC to keep it to SLAM level with the lower CYA.

Todays Readings:
FC 1.5
CC .5
TC 2.0
CH 100
TA 130
20 CYA
7.8 PH

 

[reggiehammond]

Please fill out your signature with all equipment. Given the clarity issues and low FC reading today; you need to SLAM again. CYA could be raised, as well to give more buffer to summer sun. If you are on a vinyl pool, the CH may be ok, if not, that's asking for trouble.

 

[Texas Splash]

Welcome! I would also ask two more questions:
- Are you on a well?
- Can you post a pic of the water?

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[Crashedmatrix]

Please fill out your signature with all equipment. Given the clarity issues and low FC reading today; you need to SLAM again. CYA could be raised, as well to give more buffer to summer sun. If you are on a vinyl pool, the CH may be ok, if not, that's asking for trouble.

I'm thinking you are right. I spent more time SLAMing and clearing this pool than swimming in it this year. Now that the water is starting to get warm enough to swim again it turned into a mess and the family will need to wait to swim another couple weeks. Good thing we have a YMCA membership and a public pool close by .

Signature updated.

 

[Texas Splash]

No doubt your well water is also reacting during the SLAM Process, but you have to be algae-free before treating for iron. During the SLAM, you might consider using polyfill to help capture iron.

 

[Crashedmatrix]

No doubt your well water is also reacting during the SLAM Process, but you have to be algae-free before treating for iron. During the SLAM, you might consider using polyfill to help capture iron.

I'm a bit confused because I brushed, vacuumed, and SLAMMed this pool till it was clear and passed the OCLT with flying colors which took a couple weeks of SLAMMing. It passed the OCLT nearly a week before it got crystal clear, but I kept chlorine at SLAM level till it was completely clear. It was cloudy blue for over a week. Then it finally was crystal clear for 2 whole weeks but the water was a little too cold to swim so we had to stay out of it. During that time I kept the water balanced within spec and kept the pool vacuumed and skimmed. Then it rained for a couple days and started to warm up again. That's when I went out and vacuumed and stirred up a giant problem apparently. I've never let my PH and chlorine levels get out of hand after the pool was successfully SLAMMED. The FC was a little low today but that was before I added Chlorine to the pool this morning.

I've never had an issue with my water turning brown or anything like that. The water has been in the pool for years. It rains enough where I have to vacuum to waste to lower the water level. I vary rarely have to add well water besides when I top it off at the beginning of the year. It was clear last year and all winter. What tells you there is iron in the water and why did the algae come back?

 

[Texas Splash]

You list well water in your signature. For most owners across the country, that equals iron. In your case, if you rarely use it other than initial opening, your iron level might be relatively low. Hard for us to know. But your thread title stats going from green to teal, so those odd color changes make us think of iron.

As for the algae, it's possible that a combination of rain and a slightly lower FC level allowed organic matter to brew. That's all we can assume from your description. Some people have a well-balanced pool then get enough inches of rain that don't have enough time to mix well and get chlorinated, resulting in a blast of organics on a layer of the water. Perhaps that happened in your situation.

 

[Crashedmatrix]

But your thread title stats going from green to teal, so those odd color changes make us think of iron.

The color cycle During SLAM went as follows: Green, teal, cloudy blue, clear
It remained clear for 2 weeks no issues with typical pool maintenance and chemistry. Then it rained a few days so I didn't vacuum it for a week. Something else I should add, there are trees near on side of my pool. This might have some something to do with my problem, but the last few years I kept my pool clear with test strips.
Rain stopped and the pool was still crystal clear but I noticed some dirt on the bottom of the pool so I thought I should vacuum to waste and get that out of there.
It was very difficult to get off the bottom so it took some scrubbing. During the scrubbing it started to puff up into the water and started mixing.
after all the vacuuming was all done the water was cloudy blue again.
Next day it was teal and now its getting greener, but I can still see the bottom of the ladder. just hard to make out the pattern at the bottom of the pool now.

 

[Texas Splash]

It was very difficult to get off the bottom so it took some scrubbing.

That is odd. Rain and debris will normally just sit at the bottom like dirt and should not require such aggressive brushing. You mentioned the trees, so I wonder if some gummy junk was washed off of the trees into the pool and settled at the bottom?

 

[JJ_Tex]

why did the algae come back?

Unfortunately when you let your FC drop below the minimum, you risk getting algae. Yours was under the minimum FC for your CYA when you posted earlier.

After your SLAM, make sure you treat the minimum like a cliff that you never ever want to go near. I would suggest dosing your chlorine to the top end of the FC target range so that as the chlorine gets used up it stays in the target FC range for the rest of the day.

 

[Crashedmatrix]

Wanted to come back and report that Texas Splash was very close to solving my problem. It wasn’t iron from the well water it was sediment. I have sediment filtration for my house but not for the outside spigots. After I built the bucket poly fill filter and ran it for several days without any noticeable changes in water clarity I decided to top the pool off with the hose. I put a couple of socks around the hose and began to fill. Sediment instantly appeared on the sock. The sediment was settling on the bottom of the pool as “dirt”. Neither the sand or bucket poly fill filter would remove it. I flocked and vacuumed to waste a few times and the pool is crystal clear again. The key for me is to not let the sediment stay on the pool floor very long because it starts to attach itself to the liner. It requires a lot of scrubbing to get it off then it starts mixing and turning the water teal instantly. Thanks for the help Texas.

 

[Texas Splash]

Sediment instantly appeared on the sock.

Outstanding! Great catch.