Water tests fine, but funky smell and some green on masonry - what to do?

[stimpsonjcat]

So we haven't been in the pool for a few weeks.

I had one extended absence and the wife did not check as instructed while gone.

Got back, and noticed a funky odor, chlorine was low but OK and water looks fine. Added hypo and water tests are all fine, maybe 1 on CC I never had before.

But still funky smell. Looking around I have some green on the masonry at the pool edge the cover covers up and also a bit on the plaster near the first step. I suspect this is algae forming because those areas are always moist. The pool is only 7x12, and the cover is suspended on cedar slats that span the 7 foot distance. The cover rolls up when we use the pool. So there is a 4-6" area on both sides the coover sits directly on the top masonry and this covered area is where the algae is forming.

I am planning to take the roll-up cover off and clean it and also clean all the masonry around the pool. Is it OK to just use some water with cal-hypo in it to make a bleach solution for this? Should I add any muriatic to that mix?

 

[duraleigh]

Everything starts with valid test results. Can you post them for us and tell us the kit you used?

You surely will need to SLAM but shoot us the test results first.

 

[JamesW]

I wouldn't use cal hypo to make a bleach mix. Just use bleach for any bleach needs.

Never add acid to chlorine because you will get a very dangerous toxic cloud of chlorine gas.

Never mix any chemicals.

Did your cyanuric acid level suddenly drop?

 

[stimpsonjcat]

TF-100 kit

FC - 6
pH - 7.8
TA - 60
CH - 300
CYA - low...maybe 10-20, but I have never run it very high as the pool is completely enclosed inside a room. So 'suddenly', no, but I never kept it high.

 

[stimpsonjcat]

For clarity (heh) there is no discoloration of the water. Perfectly clear. And a cup of test water away from the pool has no odor other than chlorine.

Just read the SLAM procedure. Going to go add stabilizer per the recommendation on pool math.

 

[mknauss]

With those test results your water is very aggressive to your plaster. I assume you will be raising your pH very soon.

Good luck.

 

[stimpsonjcat]

With those test results your water is very aggressive to your plaster. I assume you will be raising your pH very soon.

Good luck.

I am an idiot...I meant 7.8

I have added acid to bring it down. I keep fighting this, always having to add muriatic to bring it back down.

It also seems to constantly have a rising CH. Which in the summer I beat down by adding make up water for the loss I get in my homebrewed solar system. This winter I will be watching that.

- - - Updated - - -

Alright, added about 35oz of liquid stabilizer per TFP pool math calculator.

It's nice to have the endless pool rig in there as it makes stirring the pot easy to do, and shuts itself off after 30 minutes.

I'll see what happens tomorrow and report back.

 

[mknauss]

Previously you mentioned using cal-hypo. That is what raises your CH. Calcium Hypochlorite. Switch to liquid chlorine - sodium hypochlorite.

pH rises because I suspect the Endless Pool creates a bit of aeration. Need to monitor your TA as it could fall unless you add higher TA fill water.

Take care.

 

[stimpsonjcat]

Previously you mentioned using cal-hypo. That is what raises your CH. Calcium Hypochlorite. Switch to liquid chlorine - sodium hypochlorite.

Holy cow, been doing it to myself!

I will try the sodium hypochlorite and see how things go.

Many thanks!

 

[duraleigh]

Back to your "funky smell" issues. I think you are not brushing often enough. In an indoor pool, you won't need more chlorine than you have now, but it seems like it might be getting light use.......or little circulation. Brush the surfaces to "loosen" the organics on your pool surfaces.....exposing them to fresh chlorine.

I do not see a rteal need to SLAM but rather just more hands-on maintenance. I suspect air circulation might be contributing so let your pool "breathe" as much as is practicable.

20-30 ppm CYA is fine for an indoor pool and you should be keeping CONSTANT chlorine about 2-4 ppm.

Please read "The "ABC's of Pool Water Chemistry" up in Pool School.........it'll give you a better grip of the chemistry and you can get your pool back fresh as a daisy!

 

[stimpsonjcat]

Yes, I suspect the problem is the trapped moisture below the cover.

I am ordering a new cover and will just let it float on the pool surface. The wife wanted the more rigid solution because she was afraid the dogs might jump in and drown. They have shown no inclination to do so and are rarely in the room, so the floating solution is now approved.