In Miami Florida I have a 10K gal IG plaster pool, 35 years old. My problem is that green algae rapidly reappears on the bottom and sides soon after shocking with 2.5-5 gallons of 10.5% bleach. After reading advice here, I added PolyQuat 60%. Initially 12 oz, then 3 oz the next week. Still, when I sweep the bottom I see green clouds. Measurements: pH 7.4, FC 6, alk 70. Pinch-A-Penny measures pH 7.6, FC 4, alk 100, Calcium 230, Stabilizer 60, Phosphate 100. I use the pool only once or twice a week. I vacuum after I shock. There is a 70 square foot cartridge filter and a 1 HP pump. I stock the floater with two tablets of trichlor. I'm adding 3-6 cups of 10.5% bleach daily. The persistent green algae has been there for years and I'm getting very tired of it. I used to use a bromine solution weekly and that worked okay, but I'm trying to get away from that.
Green Algae Never Really Goes Away
- Thread starter greenthumb
- Start date
Welcome Well, first I have to recommend getting yourself a good test kit (see my signature). It is just too difficult to maintain a pool with good consistent levels and pool stores are notoriously off.
The most important thing right now is knowing your CYA (stabilizer) level {possibly 60 if you believe them ... I would not, but for now lets assume that is correct} If you are a CYA of 60ppm, you MUST maintain a FC level between 5-7ppm ... never let it drop below 5ppm. Since you see algae, you MUST go through the shock process with a shock FC level of >24ppm (you and the pool store can not test this high without a FAS-DPD FC/CC test). Start reading this Turning Your Green Swamp Back into a Sparkling Oasis and other articles in Pool School.
Have you recently replaced a lot of water in your pool?
How long have you been using tablets? If it has been awhile, I have my doubts about your CYA being only 60ppm
You MUST STOP using the trichlor!!! They are continually adding CYA and soon (if not already) your levels will be too high to maintain a clear pool without a partial drain.
You can have a crystal clear pool using only liquid chlorine/bleach if you do your homework reading Pool School ... and we can help lead you through the process of clearing up your pool.
Your first step should really be a GOOD test kit to confirm the CYA level ... knowing that we can attack the algae by properly adding ONLY what the pool NEEDS using the poolcalculator.com ... and not what the pool store wants to sell you.
What we have here is a failure to communicate...
Dumping a load of chlorine in once a week is not shocking the pool. To do it right, it might take several days, maybe even a couple weeks. And lots and lots of bleach.
I echo jblizzle. A good test kit is a must. Armed with it, the article linked in his post, and the pool calculator, you can have a pool that is crystal clear all summer long. It can be the envy of all who see it. Really.
Dumping a load of chlorine in once a week is not shocking the pool. To do it right, it might take several days, maybe even a couple weeks. And lots and lots of bleach.
I echo jblizzle. A good test kit is a must. Armed with it, the article linked in his post, and the pool calculator, you can have a pool that is crystal clear all summer long. It can be the envy of all who see it. Really.
jblizzle said:
Thanks for replying. I have a Taylor K-1004 test kit. Because the FC test only goes up to 5, I dilute my sample with distilled water to measure higher levels. I'd like to get going on this and not wait for another test kit to arrive. I use 10.5% pool store bleach ($5 for 2.5 gal) because it costs half as much as grocery store 6% bleach, at least the way I calculate it. If I go by the measured CYA of 60 and a target FC level of >24, then one 2.5 gallon jug should be more than enough. But I've done this many times, combined with adjusting pH to below 7.4 before I start, and vacuuming the pool after, and there is algae on the pool bottom within 24 hours. The FC level remains above 15 during this time. It's not a lot of algae, but if I sweep the bottom I see it come up in a cloud. So what am I missing?
Well, first I have to recommend getting yourself a good test kit (see my signature). It is just too difficult to maintain a pool with good consistent levels and pool stores are notoriously off.
The most important thing right now is knowing your CYA (stabilizer) level {possibly 60 if you believe them ... I would not, but for now lets assume that is correct} If you are a CYA of 60ppm, you MUST maintain a FC level between 5-7ppm ... never let it drop below 5ppm. Since you see algae, you MUST go through the shock process with a shock FC level of >24ppm (you and the pool store can not test this high without a FAS-DPD FC/CC test). Start reading this Turning Your Green Swamp Back into a Sparkling Oasis and other articles in Pool School.
Have you recently replaced a lot of water in your pool?
How long have you been using tablets? If it has been awhile, I have my doubts about your CYA being only 60ppm
You MUST STOP using the trichlor!!! They are continually adding CYA and soon (if not already) your levels will be too high to maintain a clear pool without a partial drain.
You can have a crystal clear pool using only liquid chlorine/bleach if you do your homework reading Pool School ... and we can help lead you through the process of clearing up your pool.
Your first step should really be a GOOD test kit to confirm the CYA level ... knowing that we can attack the algae by properly adding ONLY what the pool NEEDS using the poolcalculator.com ... and not what the pool store wants to sell you.
Please read How to Shock your Pool up in Pool School....it is a process...not a one time dose.
Who tested the CYA? If it was from anything other than a turbidity test, it could be way off and that would have a big effect on your shock process.
I still must recommend getting a kit with a FAS-DPD chlorine test as it is going to be hard to reliably measure FC on the order of 24ppm by dilution.
You do not seem to be actually following the shock procedure. You can not just put one bottle in and walk away for a few days. You have to dose up to shock FC level and HOLD IT THERE until your water is clear. If the FC fall to 15 from 24, you have already failed. You have to get the FC up above 24 and then measure and keep adding FC to keep it above 24 ... this may require measuring and adding FC every hour for awhile before the FC level stops dropping.
Review the link in my first post. We can get you to a clear pool, but you have to be able to measure your levels and then add the appropriate amount of chemicals to keep the levels correct using the poolcalculator.com
You do not seem to be actually following the shock procedure. You can not just put one bottle in and walk away for a few days. You have to dose up to shock FC level and HOLD IT THERE until your water is clear. If the FC fall to 15 from 24, you have already failed. You have to get the FC up above 24 and then measure and keep adding FC to keep it above 24 ... this may require measuring and adding FC every hour for awhile before the FC level stops dropping.
Review the link in my first post. We can get you to a clear pool, but you have to be able to measure your levels and then add the appropriate amount of chemicals to keep the levels correct using the poolcalculator.com