Never before seen type of algae or maybe bacteria???

[Colleencauline]

This is my first post for help as I have come across an issue that I believe to be monsoon weather related. I have a pool route in Arizona and we are in the summer monsoon rain season. As much as I love the rain, it can cause all kind of chaos for the pools. I have encountered my share of green, mustard, and even the super fun black algae. However this past week I have come across something all together new and never before seen. I have 2 pools in which I have seen this... one residential that gets no use, and one commercial that gets very little use. Both of these pools have water that is beyond needing replacement... the residential has agreed to a draining this coming week and the commercial client will continue to fight me over water change and blame me for his water problems even though I explained 100 times over what his problem is....bad water... bottom line. Thanks to Richard I do understand the FC/CYA relationship as well, however I will not and do not keep the FC levels as high as they require because one it is not healthy levels at that point & my prices are structured for "normal operating conditions". They both have sand filters TR-60 and one is 17,000 and the other is 24,000 gallons.

TEST RESULTS (commercial) (Residential)
FC 5 5
CC 0 0
PH 7.6 7.4
TA 110 100
CH 1300 1200
CYA well over 100 (even did the dilution test, so safe to say well over 200) for both pools
TDS 1800 1920

The problem that has popped up this past week is probably not an algae but not sure. It looks like grey spots that adhere itself to the plaster and is all over the deep end in one pool and in the areas of the steps in the other pool. I thought it was black algae at first but was far to spread out and far to big to be black algae. Yes, I looked at it closely and tried to scratch it off with my finger nail and sometimes it will brush right off and some of it does not want to come off with out elbow grease and a ss brush. For lack of better description it looks like grey snowflakes and the size of the spots are a little smaller than the size of an eraser on the end of a pencil or smaller. I figure this is rain related just because we have had crazy rains this season and both pools did this the same week after some crazy and brutal storms went through town. Any thoughts or ideas are greatly appreciated. Thanks much.

 

[zea3]

Hi, welcome to TFP!

You need to explain to the commercial client that the problem with their water is calcium and CYA far, far above recommended levels. Their are only two ways to remove excess calcium or CYA and that is to drain and refill, or to have the water cleaned with a reverse osmosis treatment. There is a company in Arizona that does reverse osmosis treatments in pools but I do not know if they operate in your area. You may want to do a google search on reverse osmosis pool treatment and see if you can track them down.

If the client refuses to drain and refill or reverse osmosis is not an option either, then the water will be very difficult to manage and possibly cause damage to the pool. It sounds like the gray flakes are scale. Scrape a few off and put a drop of muriatic acid on them. If it foams up it is scale. When calcium is high you need to keep the pH around 7.0-7.2 and the TA 70-90 to try and prevent scale formation, although if calcium is as high 1300 that may not help.

As far as the FC/CYA relationship goes, if you do not keep the FC in proper ratio to the CYA level you will get algae. 2 ppm of FC in an unstablized pool is harsher than 10 ppm in a pool with 100 CYA. I understand it not being cost effective, but this is just one reason why pools with high CYA are difficult to manage even if you dose them with liquid chlorine every day. High CYA makes it impossible for a weekly pool service to be effective.

 

[Patrick_B]

Welcome to the forum Colleen. Yea, both these pools need a major drain and refill...or the RO treatment. If it was my client, I would advise that one of these options was imperative and there would be a very high potential for continuous problems. Potential for scale is extremely high, almost certain really. They will continue to fight Algae problems as long as the CYA remains in those ranges. I do wish you good luck, and let us know how it all turns out.

 

[SouthernClass]

If it were my client I would drop them. Obviously you have the knowledge available to you to run a beautiful properly balanced pool ( since your part of this forum . If you ever had interested future clients that wanted to see some of your work or to call some references, it would be detrimental because even you said the client is blaming you but refuse to take the proper steps. I don't know if you dropping them is an option and obviously I can't tell you what this mysterious outbreak is, just figured I would throw my opinion out. Do these clients have to sign contracts? Hopefully you will get this sorted out soon.

 

[chem geek]

Thanks to Richard I do understand the FC/CYA relationship as well, however I will not and do not keep the FC levels as high as they require because one it is not healthy levels at that point & my prices are structured for "normal operating conditions".
:
TEST RESULTS (commercial) (Residential)
FC 5 5
CC 0 0
PH 7.6 7.4
TA 110 100
CH 1300 1200
CYA well over 100 (even did the dilution test, so safe to say well over 200) for both pools
TDS 1800 1920
:
It looks like grey spots that adhere itself to the plaster and is all over the deep end in one pool and in the areas of the steps in the other pool. I thought it was black algae at first but was far to spread out and far to big to be black algae. Yes, I looked at it closely and tried to scratch it off with my finger nail and sometimes it will brush right off and some of it does not want to come off with out elbow grease and a ss brush. For lack of better description it looks like grey snowflakes and the size of the spots are a little smaller than the size of an eraser on the end of a pencil or smaller.

What you describe sounds like calcium carbonate scaling but if I assume 200 ppm CYA then the CSI is around +0.25 for the commercial pool and about 0 for the residential pool so unless the pH was higher previously or some numbers are wrong such as the TA level then I'm not sure if it's really scale. If Trichlor pucks were used, not only should the CYA have risen over time, but the TA as well since the pH was maintained (the TA would have only dropped if the pH wasn't adjusted). If you scrape some of this gray stuff off and remove it from the pool, see if it fizzes if you add acid to it in which case that would confirm calcium carbonate scale.

A high FC level when the CYA level is high is not unhealthy since the health aspect has to do with the active chlorine level which is related to the FC/CYA ratio and not to FC alone. However, for the commercial pool you may have no choice where state codes say that a public or semi-public pool must have an FC of 1 to 3 ppm.