Balanced pool still fighting algae

[Adam Garcia]

Long time reader first time posting. In laws bought a house with a 30,000 gal inground liner, with sand filter. I have a salt water pool and rarely have any issues. Have never had to deal with a manual dose chlorine pool. I have kept the pool balanced but have had to SLAM it twice already to clear it and it still comes back after a few days. We have had way above average rain this year. Is that playing a role? They have alot of trees in there vicinity also. Readings are as follows using k2006

FC 3
TC 3
TA 100
CH 280
CYA 30

I have had zero issues with my SWG pool but am maybe missing something on a chlorine pool? Thanks for the help!

 

[Texas Splash]

Hello and welcome to TFP! Well, there's no huge chemistry differences between manually adding chlorine (bleach) and the SWG. The only difference is the SWG makes the FC for you from salt and you don't have to carry jugs around. Other than that, same basic principles. The rain may have resulted in some water exchange thereby lowering their CYA. To have algae means that at some point, your in-law's pool saw a drop in FC long enough to allow algae to bloom. So now a SLAM is in order correct? No problem. Just follow everything listed on the SLAM page (link below) and they'll be fine. A couple highlights:
- Lower pH to 7.2 before starting the SLAM
- Increase FC to "12" based on that CYA of 30. Maintain the FC 24/7 until all 3 SLAM criteria are passed.

Follow everything else on the SLAM page and it will work. Good luck!

 

[cowboycasey]

Welcome to TFP

Try going up to 5FC, what you're use to is constant adding of chlorine and now it is added all at once and has to stay above 3 for 24 hours or until you add again.. the trick is to test and add at the same time every day, most do it at night (6pm or so) if you take it to 5FC and the next night it is at 3FC you should be good...

One thing also, at CYA of 30 in texas it may be low, most people have much better luck at CYA 50 because the sun blows through CYA of 30 and eats your FC (that's why your SWG is working better at CYA 80)

I hope this helps