Scale, algae, other?

[Mend]

First off, Thank you. This site has been a wealth of knowledge. Almost too much for first time pool owner such as myself. Sorry for the length of this post but I want to give as detailed info as possible.

Pool background- Purchased home with poorly maintained pool. Removed safety cover this May and it looked and smelled like a swamp. I immediately started adding tri-chlor to shock, vacuumed to waste, back washed, and everything I could think to do at the time. Had pool store test water. They had me to add CYA, Cal-Hypo, and Soda ash. Pool took weeks to even come close to clear with still a greenish tint.

After lots of money and frustration I stumbled upon this site. I read pool school many times and came to the conclusion that everything the pool store had me do was all wrong. I bought a test kit (K-2005). My CYA was at 90 FC was zero (despite) constant addition of cal-hypo. I have done a partial drain and refill, SLAM (twice), and began using the BBB method with beautiful results. Pool is finally holding FC but still some problems.


First I have brown stains on anything white. Stairs, skimmer, light bezel, returns. Scrubbing does nothing even on stairs with straight bleach on exposed steps during drain/refill.

Also a white/brown scale on bottom of deep end and up slope against water flow.

And green/brown stains in corners of liner and at certain spots in shallow end.
Any suggestions are greatly appreciated.

FC - 10
TC - 10
CC - 0
PH - 7.1
TA - 100
CYA - 35
CH - 500 (fill water is at 100)

 

[Richard320]

How long has the pool been clear? If those are organic stains, which is likely, then a few weeks of adequate FC should start lightening them. Scale may dissolve back into solution if you maintain a Negative CSI. Plug test results into http://www.poolcalculator.com/ and it will tell you what the CSI is. Then play with target values a little and see what lowering TA can do for you, and again, give it a few weeks.

If things still look bad, then start worrying about metal stains. The search feature should help you locate plenty of information about stains.

 

[Mend]

Thank you for the response. The pool was off and on clear then back to forming algae for about 6 weeks before getting a test kit and following BBB. It has been crystal clear with no algae growth for about 2 weeks. I have been trying to maintain low PH and CSI for the last week and it does show minor improvement. I thought they may be organic due to the rapid consumption of FC but now that seems to have stabilized. I am going to try to keep FC fairly high to make sure. I am assuming that a CSI of -.18 was good for this from reading other posts. The stains on the bottom are rough like sand paper so I was unsure that it would be organic.

 

[Richard320]

Thank you for the response. The pool was off and on clear then back to forming algae for about 6 weeks before getting a test kit and following BBB. It has been crystal clear with no algae growth for about 2 weeks. I have been trying to maintain low PH and CSI for the last week and it does show minor improvement. I thought they may be organic due to the rapid consumption of FC but now that seems to have stabilized. I am going to try to keep FC fairly high to make sure. I am assuming that a CSI of -.18 was good for this from reading other posts. The stains on the bottom are rough like sand paper so I was unsure that it would be organic.

Rough is Calcium scale. Since you don;t need to worry about leaching Calcium from the plaster walls, you can target a lower CSI. Just don't lower the pH too much to do it, or you will have burning eyes and a slim chance of equipment damage. If you are dissolving the scale, look for CH to increase.

It's a shame you can't use a steel brush on it, because I have a theory that the microgrooves the bristles scratch in the scale promote dissolving, the way crushed ice melts faster than the same weight of block ice.

 

[Mend]

That's great news. I have seen the scale slowly receding and My CH has been going up even after discontinued use of the cal-hypo. Maybe I just need to be more patient and keep following what I've learned here. I can't say enough how huge a help this forum has been.