Do not want algae, ever

[Wildcat]

I have posted my learning process elsewhere. Changing to BBB from Trichlor pucks. In spite of high CYA, 160, in spite of my ignorance for the past 5 years since I bought this house with pool, I have not had algae that I know of. But now since this site has made me more anal about my water I have a question. My pebbletec pool shows no signs of algae, not at waterline or walls or floor. Nothing else in pool except a light, no ladders or slides. But what I do have is 5 or 6 dark spots about the size of a quarter, one the size of a small saucer, on the bottom of the pebbletc. They do not respond to nylon brushing. Any concern it is algae? Since I have never had it I almost do not know what to look for. Hopefully having kept my FC at 10-12 (luck only) kept troubles away.

CH. 650
TA 110
PH 7.5
FC. 12
CC. 0
TC. 12
CYA. 160

 

[BoDarville]

Can you post a pic of the dark spots? In the meantime, try rubbing a trichlor tab on one of the spots for about a minute. If the stain fades, then it is organic. If not, try holding/rubbing a Vitamin C tablet on the stain for at least a minute. If the stain fades, then it is a metal stain. Report back on what you find.

BTW, if your CYA is still 160, you will need to drain and refill a substantial amount of your water. But first, let's make sure the spots you are referring to are not caused by metals. If they are, there is a treatment you would do before the drain & refill that will also remove any metals.

 

[Wildcat]

Thanks, I will see if pictures work,probably next weekend. The former owners used Pool Frog, and ozonator and a magnetic device but no metals I know of. Most of the spots are in the deep end, hard to apply a puck or Vitamin C to them. Maybe I will try a light wire brushing, will that hurt pebbletec?


Yes, I know for many reasons a drain is in order. But will wait for winter as it is 95-105 here this time of year and dilution is more costly if I bring it down a little at a time. Will try and coare cost of water to cost of bleach. Will pick up 15 jugs of 81 oz bleach at local Lowes tomorow, probalby 6% but still good price for over 1/2 gallon.

 

[JohnN]

I believe the Pool Frog does in fact use metals. Have you ever had your pool water tested for metals? I think the pool store usually gets this test right.


Sent from my iPhone using Tapatalk.

 

[Wildcat]

I will get it tested. But I have not used the Pool Frog in 4 1/2 years. I may be over worried, the stains are small

 

[JamesW]

There are several possibilities for the dark spots. Some possibilities:

1) Black algae
2) Copper stains
3) Gunite showing through thin plaster.

If you do use a wire brush, make sure that it is a good stainless steel model made for pool use. Regular steel bristles tend to break off and cause rust stains in the pool.

In your area, there is probably a reverse osmosis service available.
http://www.tucsonwatertreatment.com/Services
http://jspsi.poolhelp.com/ARTICLES/JSPS ... p21-24.pdf

 

[Wildcat]

Thanks, will consider reverse osmosis. Will have to balance cost vs. drain and refill. From what I read RO costs $400-500

 

[Donldson]

The pool frog does use copper. If you haven't done any major water changes since it's been used there is still copper in the water, especially if they used it for a long time.

I would strongly consider the RO treatment. It is costly but will remove the CYA, CH, and copper from your water. Then you can adjust your CYA and CH to where you need them and never have to worry about the copper again.

 

[Wildcat]

I appreciate all the comments, but if it is residual copper stains and only 4 or 5 small patches it won't get any worse as the Pool Frog has been gone for 5 years. As long as it is not algae

 

[Shane1]

I have a pebble sheen finish that has a few dark spots as well. The spots got worse when I tried the vitamin C tablets so be carefull if you go that route. There is another poster that had the same results. After the vitamin C tabs made things worse I tried a nice SS brush and pouring MA down a PVC tube directly on the stains and tried a metal removing method. Nothing has changed the stains. I'm not sold on the metal removal method I tried so I'm going to revisit it and use something different next time. If that doesnt work I think the only thing left is to try an acid wash. I'll try and find my post which has pics in it, that way you can compare and maybe we can get to the bottom of it.

 

[Shane1]

Here is the link to that thread.
stains-on-pebble-sheen-after-vitamin-c-t43776.html

 

[Wildcat]

That is exactly what my stains look like! They do not seem to be getting worse, are yours?

 

[Shane1]

That is exactly what my stains look like! They do not seem to be getting worse, are yours?

No they have not changed since I put the vitamin C tabs on them.

 

[Wildcat]

I am thinking there is no way this is black algae as it does not seem to change. My plan is to monitor and if I see no change I will presume it is some ancient unknown stain and forget about it. What do you think, Shane 1?

 

[Shane1]

Mine is 100% NOT black algae, I would bet yours is not black algae. I plan on trying another type of copper remover as my water did test positive for it. Plus since they got worse after the vitamin C application my money is on copper. If the copper remover doesnt help I'll probably call pebble tech and see if they can help. Worst case fix is an acid wash.