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I have a 7000 gal fiberglass pool. I keep a chlorine tablet in the skimmer and I have a floater that I keep fully opened and keep two tablets in it. I read somewhere on here that someone said this is a bad idea and causes algae.
Is that so? If so why? And what should I do instead? I check my chlorine and ph and alkalinity regularly. All seem pretty normal.
Chlorine tabs are generally trichlor which is a stabilized form of chlorine and continually adds cya to your water. Over time, your cya level rises so high that you have to run higher than normal chlorine levels to avoid an algae bloom. That is the part that most people don't know and they continue to run the same chlorine levels as they always. Then they don't know why all of a sudden what has always worked to keep algae away no longer works. There is nothing wrong with using trichlor tabs as long as you monitor your cya levels. We like cya between 30-50 generally. After that, we suggest people stop using it and switch to just using bleach for chlorine. It would probably be a good idea if you posted a complete set of current water testing results taken with a drops based kit. Make sure you include a cya result.
Extensive use of stabilized chlorine tablets (trichlor) can lead to too much stabilizer (cyanuric acid) which does not break down over time. This can lead to the chlorine being less effective at sanitizing. If you search this site, you will find extensive discussions regarding this potential problem.
EricF
(See better answer above...I was too slow!)
I will post some results.
This is exactly what has been happening to me! I was humming along with the tabs thinking how great it was that I could be lazy for a few weeks at a time. All of a sudden, I got tons of algae (maybe not tons), and I'm still trying to get it cleared out. Good thing I read this post and the great reply.
Gotta load up on the bleach and stop on the tabs now.
I would be careful about pucks in the skimmer due to their low ph. If you must use pucks I would reconmend getting a puck feeder but better yet use the BBB method from the forum.
Steve
Unless your pump is on 24/7, pucks in the skimmer is a terrible idea. If you don't believe me, try putting a metal encased thermometer in the skimmer along with your pucks. After a few nights with the pump off you'll find your thermometer rusting away. Just imagine what could happen inside the copper pipes in your heater. I'm speaking from experience since I did this about 2 years ago after about one and a half seasons using Tri-Chlor tablets and then finding I had over 100 ppm Cyanuric Acid (CYA) in my water from these tablets and that I could no longer maintain satifactory chlorine levels. Yikes! What a nightmare.
So please follow the advice of others and read about the BBB method on this board. It will not only save you money, but headaches and problems too.
Richard
Ok, I have my results. Had them done on a spectrometer? At the pool store.
Saturation Index? -24
Dissolved solids 0
Free Chlorine 5.0
Total Chlorine 5.0
PH 7.3
CYA 83
Copper 0
Iron 0
Total Alkalinity 124
Adjusted total Alkalinity 100
Calcium Hardness 58
Look like my Chlorine is high according to the results they printed out. I will definitely discontinued a tab in the filter as suggested. Other than that, how do I look? How can I use the BBB solution but still utilize the remaining tabs that I have?
Everyone here will suggest you get your own test kit and do the tests yourself. Then you can believe the numbers with higher confidence.
With the CYA at about 80, you are a the minimum FC level to keep algae at bay. According to Ben's chart, http://www.poolforum.com/pf2/showthread.php?t=365 , you should probably keep it closer to 8ppm.
So I should add more Chlorine? According to the pool store's printout, 5 is high. But you are correct that algae does form on certain area over a few days if I do not scrub regularly.
Or should I attempt to reduce the stabilizer? Can I reduce the stabilizer?
The only way to lower CYA is a partial drain/refill. Your choice is either that or keep your chlorine levels higher as stated above.
Good luck.
EricF