Hello TFP! I am new to the site, but thought I would post to see if anyone has any additional insight to accompany the detailed posting about converting green algae from the main page.
Previously, I worked as a lifeguard and a CPO, however most of my work was on large systems (i.e. lap pools, not backyard). I have a general knowledge of the chemicals, but it has been a few years since I last worked on a pool. My husband is in the military, and a friend of ours is renting a house with a pool - we are stationed in the panhandle of FL. It had developed the worst algae bloom I have ever seen - but supposedly this pool was functioning reasonably well last season.
I am working with few tools - but trying to make the best of them. Having a good test kit would definitely help this situation, but as they are moving out soon I really don't want to spend $80 on the kits I'm used to unless it is really necessary. I was hoping that the local pool shops would do the testing the few times I need it - to get it back in good condition, but so far the two I have visited have proven their incompetence (or really, just a lack of looking at the big picture).
So far - I have gone through 40 lbs of granular shock and 12 gallon jugs of 10% liquid chlorine. I have also added approx. 40 oz of No Mor Problems and one full container of a granular Yellow Algae-rid product (both at the suggestion of the pool companies- I had experience with Algaecide 60 and wish I had used it instead at this point). After the first big shock and algaecide treatment there was a noticeable difference. All of the additional algae clumps on the top of the water I wasn't able to skim off disappeared and the water turned from a dark, yet clearish, forest green to a cloudy pea green. In small quantities and around the skimmers the water looks clear, but the bottom of the pool is still not visible.
I continued to shock with the granular chlorine, realizing that algae requires both diligence and patience. However, I was getting no results from shocking AT ALL. I determined that the FC level was pretty much staying at zero. At this time (it was Friday afternoon), I realized that I needed to reevaluate and be prepared for a weekend stock of chemicals. I took a water sample with me this time to get a more precise reading. The employee went away and came back and said you have no chlorine - DUH! Why do you think I came in? However, he seemed very knowledgable - and infact had maintained this very pool in his youth, so I stupidly took his advice. What did he suggest? To hit it harder - shock the **** of out it. So, I think - alright, maybe I wasn't getting the FC high enough. 20 lbs of granular shock later in less than 24 hours(his instructions indicated to shock and check until reaching FC of 5 or greater) I knew something was VERY wrong with this picture. After some thinking, I remembered that when stabilizer gets too high chlorine stops doing its job properly. So- I reevaluate on my own this time. All of that shock had obviously had a lot of stabilizer built in, so using granular was out of the question. Also, I needed to reduce my CYA - although thanks to not having a good test kit I wasn't sure of exactly what level it was, it seemed like the most logical issue.
So - I have now backwashed/rinsed, etc... until I cleaned out 6" of the top of this pool (approx 20x30 ft, 3ft - 10ft gradual slope (used to have springboard), and spillover spa). After fighting to find a good, useable water source-- the house has a nice well system for the pool only, but the well pump isn't working, the prime location is rusted shut, etc-- I FINALLY have the pool back up to normal level so the skimmers can help do some work again.
So - if anyone has made it through this novel of a post - does it sound like I'm on a better track now? I'm planning to use only liquid chlorine and continue to run the pump 24/7 until clear. The new test strips I have are indicating CYA of 30-50, but I wish I had a more accurate reading.
During this whole process, I have also been skimming out all possible debris, vaccuming, and brushing the walls/other surfaces to allow the sand filter to help me as much as possible.
If anyone can think of anything else I'm missing, please let me know. I am going to try to find another pool company that can actually do a detailed test today. If I am successful, I will post results later today.
Thanks for your time and knowledge!!!